Upload
others
View
8
Download
0
Embed Size (px)
Citation preview
Noonelikesaknow-it-all.Mostofusrealizethere’snosuchthing–howcouldtherebe?Theworldisfartoocomplicatedforsomeonetounderstandeverythingthereistoknow.Sowhenyoucomeacrossaknow-it-all,yousmiletoyourselfastheyrambleonbecauseyouknowbetter.
Youunderstandthatthequestforknowledgeisanever-
endingone,andyou’reokaywiththat.Youhavenodesiretoknoweverything,justthenextthing.Youknowwhatyoudon’tknow,you’reconfidentenoughtoadmitit,andyou’remotivatedtodosomethingaboutit.
AtIdiot’sGuides,we,too,knowwhatwedon’tknow,andwemakeitourbusinesstofindout.Wefindreallysmartpeoplewhoareexperts
intheirfieldsandthenwerollupoursleevesandgettowork,askinglotsofquestionsandthinkinglongandhardabouthowbesttopassalongtheirknowledgetoyouintheeasiest,most-accessiblewaypossible.
Afterall,that’sourpromise–tomakewhateveryouwanttolearn“AsEasyasItGets.”Thatmeansgivingyouawell-organizeddesignthat
seamlesslyandeffortlesslyguidesyoufrompagetopage,topictotopic.Itmeanscontrollingthepaceyou’reaskedtoabsorbnewinformation–nottoomuchatoncebutjustwhatyouneedtoknowrightnow.Itmeansgivingyouaclearprogressionfromeasytomoredifficult.Itmeansgivingyoumoreinstructionalstepswherevernecessarytoreallyexplainthedetails.And
itmeansgivingyoufewerwordsandmoreillustrationswhereverit’sbettertoshowratherthantell.
Sohereyouare,atthestartofsomethingnew.Thenextchapterinyourquest.Itcanbeanintimidatingplacetobe,butyou’vebeenherebeforeandsohavewe.Clearyourmindandturnthepage.Bytheendofthisbook,youwon’tbeaknow-it-all,but
yourworldwillbealittlelesscomplicatedthanitwasbefore.Andwe’llbesureyourjourneyisaseasyasitgets.
MikeSandersPublisher,Idiot’sGuides
ThisbookisdedicatedtomylovelywifeSarah,whohasalwaysstoodbymeandsupportedme.Withouther,Icouldneverhavedonethis.
ALPHA BOOKSPublishedbyPenguinGroup(USA)Inc.
PenguinGroup(USA)Inc.,375HudsonStreet,NewYork,NewYork10014,USA•PenguinGroup(Canada),90EglintonAvenueEast,Suite700,Toronto,OntarioM4P2Y3,Canada(adivisionofPearsonPenguinCanadaInc.)•PenguinBooksLtd.,80Strand,LondonWC2R0RL,England•PenguinIreland,25St.Stephen’sGreen,Dublin2,Ireland(adivisionofPenguinBooksLtd.)•PenguinGroup(Australia),250CamberwellRoad,Camberwell,Victoria3124,Australia(adivisionofPearsonAustraliaGroupPty.Ltd.)•PenguinBooksIndiaPvt.Ltd.,11CommunityCentre,PanchsheelPark,NewDelhi—110017,India•PenguinGroup(NZ),67ApolloDrive,Rosedale,NorthShore,
Auckland1311,NewZealand(adivisionofPearsonNewZealandLtd.)•PenguinBooks(SouthAfrica)(Pty.)Ltd.,24SturdeeAvenue,Rosebank,Johannesburg2196,SouthAfrica•PenguinBooksLtd.,RegisteredOffices:80Strand,LondonWC2R0RL,England
Copyright © 2015 by PenguinGroup (USA) Inc.Allrightsreserved.Nopartofthisbookmaybereproduced,scanned,ordistributedinanyprintedorelectronicformwithoutpermission.Pleasedonotparticipateinorencouragepiracyofcopyrightedmaterialsinviolationoftheauthor’srights.Purchaseonlyauthorizededitions.Nopatentliabilityisassumedwithrespecttotheuseoftheinformationcontainedherein.Althougheveryprecautionhasbeentakeninthepreparationofthisbook,the
publisherandauthorassumenoresponsibilityforerrorsoromissions.Neitherisanyliabilityassumedfordamagesresultingfromtheuseofinformationcontainedherein.Forinformation,addressAlphaBooks,800East96thStreet,Indianapolis,IN46240.
IDIOT’SGUIDESandDesignaretrademarksofPenguinGroup(USA)Inc.
eISBN:9781615647453LibraryofCongressCatalogCardNumber:2014951305
17161587654321
Interpretationoftheprintingcode:Therightmostnumberofthefirstseriesofnumbersistheyearofthebook’sprinting;therightmostnumberofthesecondseriesofnumbersisthenumberofthebook’sprinting.Forexample,aprintingcodeof15-1shows
thatthefirstprintingoccurredin2015.
PrintedintheUnitedStatesofAmerica
Note:Thispublicationcontainstheopinionsandideasofitsauthor.Itisintendedtoprovidehelpfulandinformativematerialonthesubjectmattercovered.Itissoldwiththeunderstandingthattheauthorandpublisherarenotengagedinrenderingprofessionalservicesinthebook.Ifthereaderrequirespersonalassistanceoradvice,acompetentprofessionalshouldbeconsulted.Theauthorandpublisherspecificallydisclaimanyresponsibilityforanyliability,loss,orrisk,personalorotherwise,whichisincurredasaconsequence,directlyorindirectly,oftheuseandapplicationofanyofthecontentsofthisbook.
MostAlphabooksareavailableatspecialquantitydiscountsforbulkpurchasesforsales
promotions,premiums,fund-raising,oreducationaluse.Specialbooks,orbookexcerpts,canalsobecreatedtofitspecificneeds.Fordetails,write:SpecialMarkets,AlphaBooks,375HudsonStreet,NewYork,NY10014.
Publisher:MikeSandersExecutiveManagingEditor:BillyFields
SeniorAcquisitionsEditor:BrookFarlingDevelopmentEditor:KaylaDugger
ProductionEditor:JanaM.StefanciosaCoverDesigner:LauraMerriman
BookDesigner:WilliamThomasIndexer:BradHerrimanLayout:BrianMassey
Proofreader:VirginiaVasquezVought
DIGITALOPERATIONS,LONDONDigitalProducer:AlexValizadeh
SeniorDigitalProducer:MiguelCunhaDIGITALOPERATIONS,DELHI
HeadofDigitalOperations:ManjariRathiHooda
Producer:RahulKumar
AssistantEditor:EtikaKapilDTPDesigner:ManishBhatt
OperationsAssistant:TauhidNasir
ContentsPart1:WhatIs3DPrinting?
1 The Goal of3D PrintingForBusinesses
RapidPrototyping
Manufacturing
FortheHobbyistTheMaker
CultureAToolinYour
ArsenalCommon
MisconceptionsMaterialsYou
CanUseAReplicatorin
EveryHome
TheTimeItTakes
WhatItCan
PrintFinishing
2 The Historyand Future of3D Printing3DPrintingIs
BornHull’sand3D
Systems’Contributions
TheInventionofFDMPrinting
The
DevelopmentofOther3DPrintingProcesses
TheRepRapProjectInitial
IntentionsThe
ImportanceofOpenSource
RapidDevelopment
Refinement,Availability,andYourWalletMaturationof
TechnologyAvailabilityof
PartsTheRacetothe
LowestPrice
3Manufacturingwith 3D
Printers andCNC MillsTheSimple
PrincipleBehind3DPrintingSlicingand
CreatingLayersforYourModel
ExtrudingFilament
CNCMillingand
HowItWorksSubtracting
withCAMSoftware
MillingtheMaterial
ProsandConsof3DPrintersvs.CNCMillsCostPartGeometryMaterial
MattersSurfaceFinish
UsingtheRight
ToolfortheJob
4 Types of 3DPrintersStereolithographyDigitalLight
ProcessingPowderBed
PrintingMultiJetPrintingSelectiveLaser
SinteringFusedFilament
Fabrication
Part2:AllAbouttheHardware
5 The FrameCartesianLayouts
WaysCartesian3DPrintersAreConstructed
CartesianLayoutConsiderations
TheImportanceofFrameConstructionRigidityand
HowItAffectsQualityandReliability
WhatMakesaGoodFrame
SizeMatters
6 Movement
ComponentsComponentsfor
SmoothLinearMotionRailsand
SmoothRods
BearingsStepperMotorsBeltsandPulleysWeight-Bearing
ComponentsforConvertingMotionLeadScrews
ThreadedRodsAttachmentand
ConnectionComponentsCouplersNuts
7 The ExtruderWhatIsExtrusion?TheColdEnd
DirectFeedBowdenDirectDrive
vs.GearedTheHotEnd
ThermistorHeating
ElementPhysical
DesignandMakeup
TheNozzlePrintFansUsingMultiple
ExtrudersForSupport
MaterialForFilaments
with
DifferentProperties
8 The BuildPlatformBuildPlatform
MaterialsHeatedBedsHeatedBuild
ChambersandEnclosures
SurfaceTreatmentsPainter’sTapeWhiteGluePolyimideFilm
PETFilmABSJuiceHairspray
9 ControlComponentsEndStops
MechanicalEndStops
OpticalEndStops
OtherKindsofEndStops
ControlBoardsArduinosand
ProprietaryControlBoards
ChangingorUpgradingControlBoards
SDCardSupportUsinganSD
CardBenefitsofSD
CardsLCDControllers
10 Choosing a
3D PrinterOpenorClosed?
WhatDoesItMeantoBeOpenSource?
WhyItMightMattertoYou
Assembled,Kit,orDIY?Assembled3D
Printers3DPrinterKitsBuildingaDIY
3DPrinterDeterminingYour
NeedsPrintVolumePrint
ResolutionFilamentPrices
PrinterswithUnusualDesigns
Part3:SettingUpandPrinting
11 SoftwareSetup andPrinterControlFirmware
ExplainedChoosingHost
SoftwareChoosingSlicing
SoftwareConnectingto
YourPrinterControllingYour
Printer
G-CodePrintingwith
G-CodePerforming
FunctionsManuallywithG-Code
12 Leveling theBed andAdjusting theZ HeightWhyDoesYour
BedNeedtoBe
Leveled?Manual
LevelingAuto-Leveling
HowtoAdjustYourZHeightSettingtheZ
HeightManuallyorAutomatically
Knowingthe“Correct”ZHeight
13 Slicing andPrintingConfiguringYour
SlicingSoftware
SlicerSettingsExplainedPrinter
SettingsFilament
SettingsPrintSettings
PreparingforandRunningaPrint
HostPreparation
RunningaPrint
14TroubleshootingYour PrintsWhat’sthe
Problem?Extrusion
ProblemsOverextrusionUnderextrusionJamming
PoorDimensionalAccuracy
TemperatureProblemsHotEndIsToo
HotHotEndIsToo
ColdCrackingof
PartDuetoCooling
DiscolorationofFilament
DuetoHeat
AdhesionProblemsWarpingPartComes
LoosePartBreaks
DuringRemoval
OtherPrinterProblemsBlobsStringingDroopingGhosting
Project 1:CarabinerPreheatthe
ExtruderandHeatedBed
Loadthe.STLFileSlicetheModelLoadtheFilamentExtrudeSome
FilamentStartthePrintWatchtheFirst
LayerLetthePartCool
RemovethePart
Project 2:Pencil HolderLoadthe.STLFile
andResizetheModel,IfNecessary
PreheattheExtruderandHeatedBed,andLoadtheFilament
ModifytheSlicerSettingsto
MaketheModelaCup
SlicetheModelStartthePrintWatchtheFirst
LayerRemovethePart
Project 3:RobotLoadthe.STLFilePreheatthe
ExtruderandHeatedBed,andLoadthe
FilamentModifytheSlicer
SettingsforSupports
SlicetheModelStartthePrintWatchtheFirst
LayerRemovethePartRemovethe
Supports
Project 4:Storage Boxwith Drawers
OpenYourHostSoftwareandLoadtheStorageBody.STLFile
SlicetheStorageBody
PrinttheStorageBody
LoadtheDrawer.STLFileandSliceIt
PrinttheDrawerPrintTwoMore
Drawers
Part4:3DModeling15 Introduction
to CADWhyCADCame
AboutArtistic3D
Modelingvs.CADSoftware
CADSoftwareOptions
AnOverviewofCommonCADProgram
CommandsModeling
CommandsSketching
CommandsTheImportanceof
UnitsandScaleChoosingUnitsScalinginCAD
16 ModelingTechniquesand BestPracticesPremodeling
TricksoftheTradeAssembliesand
FittingPartsPlanningan
AssemblyFittingParts
TogetherModeling
Successful3DParts
ExportingFiles
17 PracticalReverseEngineering
WhyYouShouldLearnBasicReverseEngineering
FindingtheRightMeasurementToolsDigital
Calipers:ANecessaryTool
3DScanners:NotAllThey’re
CrackedUptoBe
MeasuringthePartInferences
GeometricDesign
IntentionProportions
ModelingthePart
Project 5:MonogrammedCoasterOpenYourCAD
Programand
CreateaNewPart
ExtrudeaCircleFillettheTopEdgeCuttheLetterExportthe.STL
FileandPrint
Project 6:CustomStorageDrawerOpenYourCAD
ProgramandCreateaNew
PartExtrudetheBody
oftheDrawerCutanOpeningfor
theHandleDesignthe
CompartmentsAddaRough
HandleAddFilletsto
HandleAddRidgesfor
GripExportthe.STL
FileandPrint
Project 7: DustCollectorCreateaNewPart
andRevolvetheBody
CutaGrooveCreatetheSecond
PartandRevolvetheBody
MaketheFirstClipCopytheClipExportthe.STL
FilesandPrint
Project 8:ReverseEngineering aUseful PartCreateaNewPart
andExtrudetheBody
FillettheEdgesShelltheCoverCutOneSocket
OpeningMirrortheSocket
OpeningCreatetheScrew
HoleSupportAddtheScrew
HoleExportthe.STL
FileandPrint
Part5:AdvancedUsageandTechniques
18 Printing withOtherMaterialsWhatMaterials
AreAvailable?NylonPolycarbonateFlexible
FilamentWoodFilamentPETHIPS
HardwareNeededAll-MetalHot
EndsPrintFansHeatedBeds
andBedMaterials
PrintingTechniquesTemperatureSpeedCoolingLayer
Thickness
19 ModifyingYour PrinterAddingaFan
ShroudAddingaHeated
BedBedSize
ControlBoardPowerSupply
SwitchingtoAll-MetalHotEnds
InstallingMultipleExtruders
ExtendingAxesConvertingtoa
PCBMillAlterationsfor
LaserCuttingFindingParts
Appendixes
A GlossaryB ResourcesC Further Uses
of 3DPrinting
IntroductionInmanyways,3Dprintingisthefulfillmentofthefuturewewereallpromised.Wemaynothaveflyingcarsorrobothousemaids,butwedohaveaccesstoanalmostmagicaldevicethatcanmakeourimaginationsareality.Itwasn’tlongagothatsucha
devicewasconsideredfar-fetched,evenbysciencefictionstandards.
I’vebeenalifelonggeekmyself.AslongasIcanremember,I’vebeenbuildingthings,takingthingsapart,andputtingthembacktogether(sometimessuccessfully).WhenIwasveryyoung,thismostlymeantbuildingthingslikespaceshipswithLegos.When
Igotalittlebitolder,Igainedaccesstohammersandnails,andsuddenlyIcouldbuildthingsatalife-sizescale(thoughthismostlyresultedinlopsidedtreehouses).
Likemanygeeksmyage,Ifoundcomputersinmyteenageyears.Thisopenedupawholenewworldforme.NolongerwasIconstrainedbythecostofwoodandnails,becauseIcouldcreate
programsonoldcomputersIfoundatgaragesales.Intoadulthood,computersweremylife.Ibuiltthem,programmedthem,andrepairedthem.
Butthedesiretocreatesomethingtangibleneverleftme.IknewIwantedtomakethings.SoIwenttoschoolfordraftingandmechanicaldesign.Aftergraduating,Igotajobintheengineering
teamatabiomedicalcompany.Whileworkingthere,ourengineeringdepartmentgotaprofessional3Dprinterformakingprototypesofourproducts.
Iwas,ofcourse,instantlysmitten.Herewasamachinethatcouldproduceaphysicalpartfrommydesignsinjustafewhours.Asyoumightexpect,everyoneontheengineeringteamfeltthe
sameway.Inbetweenprototypingparts,wetookturnsprintingdesignsforourownpersonalprojects.
ButIwasn’tsatisfiedtojustprintthingsatworkwhentheprinterwasavailable,soIpurchasedaninexpensiveconsumer3Dprinter.Suddenly,IcouldprintanythingIwantedatanytime.Ifsomeideastruckme,Icoulddesignitandprintit
injustafewhours.ItbroughtbackthatfeelingofbuildingspaceshipsoutoftheLegosthatIhadn’tfeltsinceIwasakid.ThatfeelingofbeingabletocreateanythingIcouldimagine.
It’safeelingthatmostpeopleneverfindagainafterchildhood.But,ifyou’rereadingthis,Isuspectyoumightbesearchingforthatfeelingyourself.Evenif
you’vejustpickedthisbookupatthebookstoreoutofcuriosity,Ithinkthatmeansyou’reyearningtoflexthosecreativemusclesonceagain.
Andthat’swhat3Dprintingcandoforyou.Yes,it’schallenging.No,it’snotaparticularlycheaphobby.Butit’saveryrewardingone.Thefeelingofprideyougetwhenyourfirstprintiscompletedwillbeundeniable.Thesmile
thatcrossesyourfacethefirsttimeyouseeoneofyourowndesignsmaderealwillbeoneofthebrightestyou’vehadinyears.Ifyou’relookingforawaytoexpressyourcreativity,3Dprintingistheanswer.Thisbookwillhelpyouthroughthecomplicatedtaskoflearninghowtodothat.
How This Book Is
OrganizedThisbookhasbeenwrittentohelpyoureallyunderstand3Dprinting,notjusttoteachyouthebasics.Tothatend,thebookhasbeensplitupintofiveparts:
Part1,WhatIs3DPrinting?,givesyouusefulinformationonthebackgroundof3Dprintingandhowitactuallyworks.
Thisincludesthehistoryof3Dprinting,how3Dprintersdevelopedintoaconsumerproduct,andhowdifferentkindsof3Dprintingprocesseswork.
Part2,AllAbouttheHardware,teachesyoueverythingyouneedtoknowaboutthedifferentpartsofconsumer3Dprinters.Learninghowthehardwareofa3Dprinteractuallyworks
isvaluableknowledgethatcanhelpyoualotthroughoutyourjourney.(And,becauseyou’rereadingthisbook,Isuspectyou’rethetypeofpersonwholikestolearnanyway.)
Part3,SettingUpandPrinting,iswhereyoustartgettingintothenitty-grittyof3Dprinting.Thisiswhereyoulearnhowtoactuallysetupandoperatea3Dprinter.
3Dprintersaren’tliketheoldinkjetprinteryouhaveonyourdesk;they’recomplicatedmachinesthatarechockfullofconfusingsettings.Thispartgivesyoutheinformationyouneedtoreallygetstarted.Ialsowalkyouthroughfourprojectsdesignedtoteachyouhowtogetstartedwith3Dprinting.
Part4,3DModeling,goesbeyondjust3Dprinting
modelsyoufindonline,because3Dprintingisaboutsomuchmorethanjustreplicatingotherpeople’sdesigns.Canyouimagineif,asakid,youwereonlyallowedtobuildofficialdesignswithyourLegos?Itwouldhavebeenawful!Forthatreason,thisiswhereyoulearnhowtodesignyourown3Dmodelsthatyoucreatewitha3Dprinter.Inthispart,Ialsoshowyouhow
tostart3Dmodelingwithfourmoreprojectsforyoutomodelandprint.
Part5,AdvancedUsageandTechniques,iswhatyouwanttoreadonceyou’vegainedproficiencyinbasic3Dprinting.Here,youlearnhowtoprintwithexoticmaterials,howtoprintwithmultipleextrudersatonce,andsomepopularmodificationsyoucanmake
toyour3Dprinter.Youalsolearnaboutsomeunexpectedusesforyour3Dprinterthatyoumaynothaveevenrealizedwerepossible.
ExtrasThroughoutthisbook,you’llfindsomehandybitsofinformationandadvicebeyondthemaintextinsidebars.They’rebrokenup
intoahandfuloftypesforyourconvenience.
DEFINITIONThe 3D printing
industry is full of technicalterms and words that mayhave a meaning specific to3D printing. These sidebarsinclude words you’re notfamiliar with, or that have adifferent meaning in thecontext of 3D printing.
WATCH OUT!While 3D printers are
now consumer products thatare safe for the home,they’re still machines thatcan hurt you. Therefore,keep an eye out for thesewarning sidebars, which giveyou safety information andhelp you avoid accidentallydamaging your 3D printer.
HOT TIPSometimes, there are
multiple ways of doingsomething. These tips helpyou avoid hassles andheadaches. Learn from mymistakes, and take theseinto account!
FASCINATING FACTI can’t always fit the
good stuff into the mainbody of the text. Checkthese out for interestingfacts, history, and otherinformation related to 3Dprinting.
But Wait! There’sMore!Haveyouloggedontoidiotsguides.comlately?Ifyouhaven’t,gotherenow!Asabonustothebook,we’veincludedthe3Dprintingmodelfilesyou’llneedforthePart3projects,allonline.Pointyourbrowsertoidiotsguides.com/3dprinting,
andenjoy!
AcknowledgmentsIcouldneverhavewrittenthisbookwithoutthesupportofmyfriendsandfamily,whohavealwaysencouragedme.MybeautifulwifeSarah,whoputupwithmeworkinglateintothenight.MyfriendsDaniel,Sean,Sam,Zach,Amanda,andJonathan,who
werealwayshappytostartnewhobbieswithme.Myin-lawsBonnieandJavad,whosomehowbelievedinmewhennooneshouldhave.MyparentsSharonandDavidandsiblingsDanielle,Lynnze,andNathin,whohadtolivewithmeforsolong.Tom,Beth,andMike,whonurturedmyinnergeekwhenIwasyoung.AndmydogCalaveras,whokeptmecompanywhileIwrotethis
book,andbecauseshe’sjustsodarncute.
I’dalsoliketogiveaspecialthankstothefinefolksatAlephObjects(especiallyHarrisKennyandJeffMoe),whowerekindenoughtolendmeaLulzBotTAZtouseforthisbook.TheRepRapprojectalsodeservesahugeamountofcreditformaking3Dprintingpossibleforhobbyistsandconsumers.
Special Thanks tothe TechnicalReviewerIdiot’sGuides:3DPrintingwasreviewedbyanexpertwhodouble-checkedtheaccuracyofwhatyou’lllearnhere,tohelpusensurethisbookgivesyoueverythingyouneedtoknowabout3Dprinting.Specialthanksare
extendedtoAaronTrocola.
TrademarksAlltermsmentionedinthisbookthatareknowntobeoraresuspectedofbeingtrademarksorservicemarkshavebeenappropriatelycapitalized.AlphaBooksandPenguinGroup(USA)Inc.cannotattesttotheaccuracyofthisinformation.Useofa
terminthisbookshouldnotberegardedasaffectingthevalidityofanytrademarkorservicemark.
PART
1
What Is 3DPrinting?
Everytopicneedssomebackgroundinformation,and3Dprintingisnodifferent.Inthispart,youlearnaboutthe
historyof3Dprinting,includinghowitwasinventedandhowitenteredtheconsumerspace.Youalsolearnaboutthedifferentkindsof3Dprintingtechnologiesavailable,andtheprosandconsofeach.
Thispartalsocoverstheprinciplesbehindhow3Dprintingactuallyworks.Inadditiontohowitworks,Igooverhowitdiffersfromother
prototypingandmanufacturingmethods.Thisincludeshow3Dprintingcanbeusedbybusinesses,andwhatyoucanuseitforpersonally.
CHAPTER
1
The Goal of3D Printing
In This Chapter
Whybusinessesinvestin3D
printersWhatyoucandowith3Dprinting
Commonmisconceptionsabout3Dprinting
Itwasn’tthatlongagothat3Dprintingwasajustanobscuretechnologyrelegatedtoprototypingusebyahandfulofspecificindustries.Butinthepastcoupleofdecades,3Dprintinghasbecomeamust-have
technologyforengineeringcompanies,andevenmorerecentlyausefulconsumertool.
Butwhydid3Dprintingbecomesuchanindispensabletoolforbusinesses?Whatadvantagesdo3Dprintersgivetheconsumerandhobbyist?Inthischapter,welookatwhy3Dprintingisbecomingsopopular,whatitcandoforyou,andwhatits
limitationsare.
ForBusinessesIsaythiscompletelywithouthyperbole:3Dprintingisadreamforanengineeringteam.Atechnologythatwouldhavebeenthestuffoffantasyjustafewdecades
ago,todayitgivescompaniestheabilitytobringanideatolifequickly,efficiently,easily,andinexpensively.
Theoriginalintentfor3Dprintingwastocreateprototypesforengineers.Thisallowedthemtoquicklytestanideabeforemovingontoproductionandmanufacturing.Veryrecently,somecompanieshaveevenbeguntouse3Dprintingfor
theactualmanufacturingofproductionparts.Bothuseshaveexplodedinpopularity,andbothbenefitbusinessesinanumberofways.
Rapid PrototypingRapidprototyping,simplyenough,isanyprocessthatcanbeusedtoquicklycreateaprototypeofapart.Aprototypepartisessentiallya
testpart,andisusefulduringthedevelopmentofanewproduct(orwhenrevisinganexistingproduct).Whattheprototypeisintendedtotestisuptotheengineer,butit’scommonlyusedtotestthefollowing:
Howpartsfittogetherinanassembly
Thestrengthofthepart
Regulationcompliance
Whenanewproductisbeingdeveloped,it’srarethatasingledesigniskeptuntilproduction.Commonly,ahandfulofpotentialdesignsaretested,andwhicheverdesignischosenforproductionwillevolvequiteabitthroughoutthedesignprocess.Muchofthetestingofthesedesignsisdoneviasimulationwithcomputer-aideddesign(CAD)software,butit’salmostalways
necessarytohavearealphysicalparttoworkwithduringthisprocess.
DEFINITIONComputer-aided
design (CAD) software is atype of computer programused by engineers anddesigners to developproducts using 3D models or2D drawings. Before CADsoftware, drawings werehand drawn by drafters for
production. Now, CADsoftware can export modelsdirectly to 3D printers (seeChapter 15 for more onCAD).
CADsoftwarebeingusedtocreate
a3Dmodel.
That’swhererapidprototyping,andespecially3Dprinting,comesin.Asthedesignofaproductevolves,engineerscan3Dprintthedesignandtestit.Inthepast,prototypeswerecostlyandoftenrequiredoutsourcingtocompanieswhospecializedinproducingtheseprototypesusingtraditionalmethodslikemachining,welding,sand
casting,andothercostlyprocesses.Now,it’scommonplaceforanengineeringteamtohavea3Dprinterintheirofficewithwhichtheycanprintaprototypeinamatterofhoursandforarelativelylowcost.
Asidefromthephysicaltestingofthepart,prototypesarealsovaluableforusertesting,designproposals,andpromotion.Whenanew
productisintheearlystagesofdevelopment,itdoesn’talwayshavefundingsecuredfortheentiredesignprocess.Projectfunding(whetherinternaltothecompanyorfromoutsideinvestors)oftendependsonadesignsubmittal,whichisessentiallyaproposaloftheproductdesign.
Designproposalscanbeanythingfromasimple
explanationoftheideatoacompleteworkingprototype.But3Dprintinghasmadeitpossibletospeedupthisprocessandhasmadeitmuchcheaper.Therefore,physicalprototypeshaverecentlybecomeavirtualnecessityforsecuringoutsidefundingviacrowdsourcing.Backersofcrowdsourcingwanttoseethatadesignisfunctionalbeforetheyinvest,and3Dprintedprototypesarethe
cheapestwaytoshowthat.
ManufacturingWhilerapidprototypingisdefinitelythemostcommonuseof3Dprinting,it’sstartingtobecomeaviablemethodofactualproductionmanufacturing.Traditionally,injectionmoldingisbyfarthemostcommonmethodofmanufacturingplasticparts.
Inmassproduction,injectionmoldingcanproducehigh-qualitypartsveryquicklyandinexpensively.
Injectionmoldingisafairlysimpleprocessinconcept:moltenplasticisshotintothecavityofatwo-piece(ormore)metalmoldandcooled,andthenthemoldispulledapartandtheplasticpartisremoved.Inamanufacturingsetting,thatprocesscan
happenveryquicklyandanewpartcanbemadeinafewseconds.Itcanalsobeveryinexpensive(perpart),astheplasticitselfischeapinrawform.
However,injectionmoldinghasonecriticaldownside:thecostoftooling.Tools,inreferencetoinjectionmolding,arethemoldsandassociatedpart-specificmachineryneededtoproduce
aparticularpart.Everyindividualpartneedsitsowntooling,andthatcanbeveryexpensive.Moldsareusuallymadefromsteeloraluminumandrequireprecisionmachining.Moldmakingisaspecializedtask,andindividualmoldsstartinthethousandsofdollarsandoftenreachintothetensofthousandsofdollars.
Whenyoutakeintoaccount
thefactthatmostproductsareassembliesmadeupofmanyindividualparts(whichwouldeachneedtheirowntooling),it’sobviousthatthecostsofgettingsetupforinjectionmoldingcanbeveryhigh.That’sokayifyou’remakingthousandsofthatpart,becausethecostperpartgetslowerasthetotalquantityincreases.Butwhatifyouwanttoproduceyourpartsinsmallerquantities?Theparts
mustbemanufacturedinhugequantitiesinorderforthepriceperparttoreasonable.
FASCINATING FACTAleph Objects, a 3D
printer manufacturer basedin Loveland, Colorado, usesits own 3D printers tomanufacture some of theparts to build new printers.This “cluster” of 3D printersused for manufacturing isthe largest in the world,consisting of 135 individual3D printers.
That’swhere3Dprintinghasstartedtoenterthemanufacturingworld.With3Dprinting,thereisnohightoolingcostupfront—yourprinterscanproducewhicheverpartyouneedthemtoatagiventime.Youcanprintonepartorahundred,andyourpriceperpartwillbethesame.Thismeansyoucanmanufactureinlowquantitieswithoutincurringhugetoolingcosts.
Possiblyevenmorevaluableistheabilitytochangedesignsonthefly.Youcanredesignapartandimmediatelystartmanufacturingthenewdesignwithouthavingtopurchaseanewmold,whichmeansyourproductcanevolveinrealtimeasyouimprovethedesign.
Theclusterof1353DprintersusedformanufacturingatAleph
Objects.(PhotocourtesyofAlephObjects)
Ofcourse,3Dprintinginamanufacturingsettingdoeshaveitsdownsides,which
havekeptitfromgainingwidespreadadoption.Ifapartisgoingtobemanufacturedinlargequantities,it’sstillcheapertohaveitinjectionmolded(despitethecostofthemolds).That’sbecausetherawmaterialismuchcheaperforinjectionmoldingthanitisfor3Dprinting.Possiblyevenmoreimportantlyinmassproductionistime—aninjection-moldedpartmight
onlytakeafewsecondstomake,whilea3D-printedequivalentcaneasilytakehours.
Tobeabletokeepupwithaninjectionmoldingmachine,many3Dprinterswouldhavetoberunsimultaneously.Soinjectionmoldingisstillthebestoptionwhenpartsneedtobeproducedinmassquantities.Butforsmallquantitiesordesignswhich
needtobeupdatedoften,3Dprintingisbecominganattractivealternative.
For theHobbyistEngineering3Dprintingprototypesforcorporationsisallwellandgood,butwhat’sreallyexcitingis3Dprinting
fortheaveragepersonathome!Injustacoupleofdecades,3Dprintershavegonefrombeingtooexpensiveformostcompaniestobuytobeingcheapenoughthatyoucanrealisticallypurchaseonejusttotinkerwithathome.Butwhywouldyouwantoneinyourhome?Whatcouldyouevendowithit?
The Maker CultureTheideaofmakingstuffforfunandself-fulfillmenthasgainedtremendouspopularityrecently,butthebasicmotivationisaninseparablepartofhumannature.Thesameurgetoinventthatputmanonthemoonisalsowhatmotivatedyourfathertobuildthatbirdhousewhenyouwereakid,andit’sthesamethingthathasyouinterestedin3D
printing.Weallhavethisurgetocreate(tovaryingdegrees,ofcourse),andthemakercultureisjustamodernbrandingofthat—awaytoidentifylike-mindedpeopleandformacommunity.
3Dprintinghasbeenahugefactorinthegrowingmakercommunity,andforgoodreason.Traditionalmakeractivitiesincludethingslike
woodworkingandmetalworking.Thoseareskillswhichtakeagreatdealofpractice,patience,time,andmoney.But3Dprintingallowsyoutocreatesimilarphysicalobjectsquicklyandrelativelyeasily.It’sbecomeafairlysimpletasktotaketheideasfromyourheadandmakethemreal.
Atitsheart,makercultureisaboutcreatingthings.It’s
usingwhatevertoolsyouhaveavailablecreativelytoinventandconstructthingsthatinterestyou.Inthesamewaythatyourfathermayhaveusedahandsaw,ahammer,andnailstobuildthatbirdhouse,youcanusea3Dprintertomakewhateveryoucanimagine.Robots,electronicsenclosures,andartisticcreationsareallpossible,alongwithanythingelsethatinterestsyou.
A Tool in YourArsenalBydefinition,a3Dprinterisjustatool,andthat’showyoushouldthinkofit.Ifyouwanttohammernails,youuseahammer.Ifyouwanttocutapieceofwood,youuseasaw.Andifyouwanttomakeapartoutofplastic,youusea3Dprinter.It’simportanttothinkofa3Dprinterlikeany
othertool—averyversatiletool,butstillatool.
HOT TIPMake sure to utilize 3D
printing in the right context.It’s impractical to try to 3Dprint an entire coffee table,but you can certainly useyour 3D printer to makebrackets, drawer handles,tracks, and other parts. Likeany other tool, a 3D printerhas uses for which it’s well
suited, and some thingswhich would be betterhandled by another tool.
Asalways,it’sbesttousetherighttoolforthejob.Itmightbepossibletocutametalpipewithawoodsaw,butit’snotagoodidea.3Dprintersarenoexception—theycandoalot,butthey’renottherighttoolforeveryjob.Whenyoufirststart3Dprinting,
you’llbetemptedtotryanduseitforeverything.Birdhouse?3Dprintit!Acoffeetable?Printthepiecesandgluethemtogether!Butyou’llquicklylearnthat3Dprintersaren’tthesolutiontoeveryproblem.Withthatsaid,3Dprintersareincrediblyversatile.That’swhythey’resucharevolutionarytool.Youcanusethemtoprinteverything
fromthingslikepencilholderstoreplacementpartsforyourcar.Thisiswhatmakes3Dprintingsoexciting:ifitfitsontheprinterandit’smadeofplastic,youcanmakeit!Sure,3Dprintersaren’tthesolutiontoeveryproblem,butthey’reoneofthemostwidelyusefultoolseverinvented.
CommonMisconceptionsInessence,thegoalof3Dprinting(whetherforbusinessorconsumeruse)istobeabletoquicklyandeasilycreateobjectswithasingledevice.Toanextent,3Dprinterstodaydoaccomplishthatfeat.
But3Dprintingpresentsakindofperfectstormof
misunderstandingthatmanyfallvictimto.It’satechnologythatisverynewtoconsumers,it’scomplex,andit’sstillfairlyexperimental.It’ssomewhatreminiscentoftheearlydaysoftheinternet,whenmostpeoplestilldidn’tquiteknowwhattomakeofit.Therearesomereal-worlddrawbackswhichkeepthemfrombeingthemiracledevicesenvisionedinpopularsciencefictionandmedia.
Materials You CanUseProbablythemostcommonofthesemisconceptionsconcernsmaterials.3Dprintingtechnologyhascomealongway,andthereareavarietyofmaterialsavailabletoprintwith.But,forconsumerprintersatleast,allofthesematerialsarestillsometypeofplastic.Printing
metalisoutofthequestionforaconsumerprinter.Metals,ceramics,andothermoreexoticmaterialsarepossibleonextremelyexpensiveprofessional3Dprinters,butdon’texpecttobeprintingthemathomeanytimesoon.
Thisisprimarilybecausethetechnologyneededtoprintinmetalorceramicsisfarmorecomplexthanwhatisneeded
foraconsumer3Dprinter.Consumer3Dprintersusefuseddepositionmodeling(FDM)orfusedfilamentfabrication(FFF)technology,whichisinexpensive(seeChapter2).Buttoprintinmetal,forexample,anexpensiveandcomplexprocesslikeselectivelasersintering(SLS)isrequired.SLS3Dprintersusehigh-poweredlaserstoactuallymeltmetalpowder,and,as
youcanimagine,thosearen’tcheap.Sofornow,consumerprintersarerelegatedtojustprintingplastic.
A Replicator inEvery HomeApopularthemeinnewsarticlesabout3Dprintingistheideaofareplicatorineveryhome.It’sthepicturesquefuturefromthe
popularcultureofthe’60sand’70s:adevicethatinstantlyproducesanythingyouneedatthetouchofabutton.
FASCINATING FACTThe replicator was first
introduced in Star Trek: TheOriginal Series (and officiallynamed in Star Trek: TheNext Generation) as adevice that could recyclegarbage and waste and
synthesize food and otheruseful things. The idea is sosimilar to 3D printing that apopular line of 3D printersmade by MakerBot evenuses the replicator name forsome of their models.
Thesetupissimple:thereyouareinyourkitchencookingdinner,whensuddenlyyourspatulabreaks.Yourdinnerisstartingtoburn,andyou
don’thavetimetodriveuptothestoreandbuyanewspatula.Nottoworrythough,youhaveyourtrusty3Dprinter!Yourunover,pushabuttonortwo,andinamatterofminutesyouhaveanewspatula.Problemsolved!Thisisthekindofthingimaginedbythemediaandthoseunfamiliarwiththerealitiesof3Dprinting.
Unfortunately,realitydoesn’t
quitemeettheexpectationssetbythesekindsofstories.3Dprinterdeveloperswouldcertainlylovetobeabletoproducesuchaproduct,butit’sjustnotthecase(andprobablywon’tbeforaverylongtime).
Yourdinnerfiascowouldbequiteabitdifferentinreallifetoday:yourspatulabreaks,anddinnerisabouttostartburning.Youturntoyour3D
printerforhelp.Butbeforeyoucanstartprintingthatnewspatula,you’vefirstgottofinda3Dfiletoprintfrom.Aftersearchingforafewminutesonline,you’reluckyandfindone(savingyourselffromhavingto3Dmodelone).Nowallyouhavetodoisloadthefile,heatuptheprinter,startitprinting,andwaitanhourortwoforittoprint.Ofcourse,bythatpoint,yourdinnerisalready
burned.
Asyoucansee,asamazingandversatileas3Dprintersare,theydohavetheirlimits(ofwhichtherearemany).Eventually,youmayhavethatsci-fireplicatorinyourhouse,butwe’renotquitethereyet.
The Time It TakesThetimeinvolvedtoprint
somethingisalsoahighlymisunderstoodtopic.3Dprintingisoftenreferredtoasbeingveryfast(I’veevensaidsoearlierinthischapter).Butit’simportanttonotethatthat’sonlyinrelationtotraditionalmanufacturingmethods.Eventhesmallestprintsaregoingtotakeafewminutesatbest.Largerprintsonconsumer3Dprinterscantakethebetterpartofaday,andit’spossibleforasingle
printtotakedays(evenonanaverage-sizeconsumerprinter).Sodon’texpecttobeprintingoutpartsinstantly;it’susuallyafairlylongwait.
WATCH OUT!3D printers have very
hot parts and can be asignificant fire hazard. Onlyleave a 3D printerunattended at your own risk,and be sure to followappropriate fire safetyprecautions when printingwith it.
What It Can Print
3Dprinterscarrywiththemthepromiseofbeingabletoprintanything.Buttherearesomecaveatswhenitcomestowhatgeometryyoucanactuallyprint.Overhangsarethebiggestenemyhere.Overhangsaregeometrywhichhavenosupportingmaterialdirectlyunderneath,whichistroublesomeforobviousreasons.Thiscanbeovercomewithsupportmaterial,whichI’llgooverin
moredepthinlaterchapters,butyoushouldbeawareofthefactthat3Dprintingdoeshavedesignchallengesofitsown.
Anotherareawhere3Dprinters(especiallyconsumer3Dprinters)havedifficultyiswithprintingsmallfeatureswithfinedetails.They’relimitedbythesizeofthefilamentbeingextruded(orpushedout)fromthenozzle,
andfinedetailtendstogetwashedoutwhencommonnozzlesizesareused.Professional3Dprintersthatusemoreexpensivetechnologyarecapableofastoundingdetail,butconsumer3Dprintersarestillprettylimited.
FinishingThefinishoftheprinted
objectisoneofthemostglaringlimitationsof3Dprinting.Becauseofthenatureoftheprocess(essentiallystackinglayersofplastic),thesurfacefinishofverticalsurfacesisusuallyquitepoor.Evenonthehighest-qualitysettings,you’llstillbeleftwithaseriesofsmallridges.It’svirtuallyimpossibletogetatrulysmoothfinishstraightfromaconsumer3Dprinter.
Peopleexpendagreatdealofefforttryingtominimizethisandimprovesurfacefinish,andtherearesomepostprinttechniquesyoucanusetosmoothitout.Butdon’texpecttogetanice,smoothparthotofftheprinter.
Evenwithhigh-qualitysettings,layerridgesareevidentonthisowl
model.
Youshouldn’tbetoodisheartenedbyallofthis,though.Theseareallfairly
minorlimitations,andarejustpartof3Dprinting.Therearewaystodealwithmostofthem,andalotofworkisbeingdonetoovercomethesechallenges.It’simportanttokeepyourexpectationsfor3Dprintingrealistic,butdon’tletthesedownsidestroubleyoutoomuch.
The Least You
Need to Know3Dprintersinitiallygainedpopularityforrapidprototyping,whichremainstheirmostcommonusetoday.
Manufacturingwith3Dprintersisaviableoptionforsmall-scaleproductionbutisstillimpracticalformassproduction.
Themakerculturehasbeenfueledby3Dprintingandthe
creativeoutletitprovides.Beingabletoproduceanythinginyourownhomeisanexcitingidea,butit’sfarfrombeingareality.
CHAPTER
2
The Historyand Future
of3D Printing
In This Chapter
Thedevelopmentandhistoryof3Dprinting
HowtheRepRapprojectaccelerateddevelopment
Predictingthenearfutureofconsumer3Dprinters
Ifyouwanttounderstandsomething,it’salwaysagoodideatobeginbylookingatthehistory.It’dbedifficultto
trulyunderstandhowacarworks,forexample,ifyoudidn’tknowhowtheinternalcombustionenginewasdeveloped.3Dprintersarenoexceptiontotherule,andforsuchanewproducttheyhavequitearichhistory.
Inthischapter,Itakeyouthroughthehistoryof3Dprintingandtheeffectsofitsevolutiononyounowandinthefuture.
3D Printing IsBorn3Dprintinghasjustenteredthepublicconsciousnessinthepastfewyearsasconsumer3Dprintershavebecomeavailable.But3Dprintinghasactuallybeenaroundfordecadesintheindustrialworld.3Dprintingrevolutionizedtheway
companiesproduceprototypes,andthatprovidedthebasisforconsumer3Dprinting.
Sohowwas3Dprintingactuallydeveloped?Whoinventeditandwhy?
Hull’s and 3DSystems’Contributions
Thefirstpatentfora3Dprinterwasfiledin1984byCharlesW.Hull.Hispatentwasfora3Dprintingprocesscalledstereolithography(SLA),whichusedUVlighttocurephotopolymerresininavattoformparts.Hull,anengineerspecializinginmaterialsscienceatthetime,cameupwiththeideaforSLAwhileworkingonresincoatingsfortabletops.
DEFINITIONPhotopolymer
resin is a type of liquid resinthat solidifies into plasticwhen exposed to light(usually in the ultravioletspectrum). Manufacturerscan produce the resin inmany varieties, with differentmechanical and chemicalproperties.
ThecompanyHullwas
workingforatthetime,Ultra-VioletProducts(UVP),employedhimtodevelopUV-curablecoatingstoimprovethedurabilityoftabletops.ThesecoatingswerealiquidresinthatreactedwithUVlighttobecomesolidplastic.Whileworkingwiththisresin,Hullstartedimaginingadevicewhichcouldcurethisresininsuccessivelayerstoformathree-dimensionalobject.
HulltookhisideatoUVPandwasgrantedpermissiontoworkonaprototypedeviceonnightsandweekends,whilecontinuinghisnormaldutiesduringtheday.Thedevelopmentprocesswasnotwithoutitshurdles,oneofthebiggestbeinghowtotranslatea3DcomputermodelintoprintinginstructionsforhisSLAprinter.
Atthetime,intheearly’80s,
computer-aideddesign(CAD)wasstillinitsinfancy.3Dmodelingwasadifficultprocess,andnotawholelotcouldbedonewiththeresultingmodels.Hullknewheneeded3Dmodelsinafileformatthatcouldbeusedtocreateinstructionsforhisprinter,butnosuitablefileformatexisted.SoHullcreatedhisown:theSLAfileformat,abbreviatedasSTL,whichisstillthestandard
today.(Thesedays,becausetheSTLfileformatisusedinawiderangeofmanufacturingprocesses,STLisoftenconsideredanabbreviationforstandardtessellationlanguage.)TheSTLfileiscreatedbytakinga3DmodelfromCADsoftwareandconvertingitintoasurfacemeshconsistingofmanytriangles.ThebeautyoftheSTLformatisthatthe
numberoftrianglesdeterminesthedetailoftheresultingsurfacemesh,makingitscalable.Withthisfileformatinhand,Hullwasabletocreatesoftwaretotranslatethe3Dmodelintoaseriesofinstructionsforhisprintertofollow.
In1983,Hullsuccessfullyprintedhisfirst3Dmodel:abasiccup.Knowinghehadaviableandusefulnewmethod
ofrapidlycreatingprototypes,hefiledhispatentforSLAin1984.In1986,hispatentwasgranted,andinthesameyearhecreatedhiscompany3DSystemstodevelopandsellSLAprinters.
FASCINATING FACTWhile Charles W. Hull
did patent his SLA process,he didn’t patent the STL file
format that he developed.This has allowed STL files tobe used by other 3D printermanufacturers and even inother types of machines, likecomputer numerical control(CNC) mills. For this reason,the STL file format hasbecome the standard for 3Dprinting and CNC milling.
The Invention ofFDM Printing
Thefuseddepositionmodeling(FDM)printingprocess—atechnologyusedbythevastmajorityofconsumerprinterstoday—wasoriginallydevelopedbyScottCrumpin1989,inordertoeasetheprocessofprototypingatIDEA,Inc.,acompanyhecofoundedin1982.Crump,alongwithFDMprintingitself,alsodevelopedsomeofthenecessaryassociated
technologies(suchasABSfilament,whichI’lldiscussmoreinChapter4).
AfterinventingtheFDM3Dprintingprocessin1989,CrumpfoundedStratasys—currentlythelargest3Dprintermanufacturer—withhiswifeLisa.In2009,Stratasys’sFDMprintingpatentexpired,openingupthemarketforconsumerFDM3Dprinters,usually
referredtoasfusedfilamentfabrication(FFF)fornon-Stratasys3Dprinters.
The Developmentof Other 3DPrinting ProcessesDuringthesametimeframethatStratasysand3DSystemsweredevelopingSLAandFDM3Dprinting,
other3Dprintingprocesseswerebeingdevelopedindependently.AttheUniversityofAustininthemid-1980s,selectivelasersintering(SLS)wasdevelopedbyDr.CarlDeckardandDr.JoeBeamanwithsponsorshipfromDefenseAdvancedResearchProjectsAgency(DARPA).ThistechnologywasoriginallysoldbyDTMCorporation,whichwasthen
purchasedby3DSystemsin2001.
Meanwhile,intheearly’90sattheMassachusettsInstituteofTechnology(MIT),inkjet3Dprintingwasinvented.ZCorp.gainedthelicenseforthistechnologyandproducedinkjet3Dprintersuntil2012.OnJanuary3,2012,ZCorp.waspurchasedby3DSystemsinordertoacquiretheassociatedinkjetprinting
patentsandlicenses.
Duetotheexpirationofkeypatents,manyofthesetechnologiesarestartingtoentertheconsumermarket(orwillbesoon).ButitwasFDMprintingthatjump-startedconsumer3Dprinting.ThiswasmostlythankstotheRepRapproject.
The RepRapProject3DSystems,Stratasys,andothersrevolutionizedresearchanddevelopmentwith3Dprinting.Butformanyyears,3Dprintersremainedexpensiveandcomplextools.Thehighlearningcurvetousethemmeantthatmostusersneededspecialtraining,
andtheirhighcostmeanttheywereoutofreachforanindividualperson.ThatremainedtrueuntiltheRepRapprojectwaslaunchedin2005byDr.AdrianBowyer,anengineeringlectureratauniversityintheUnitedKingdom.
Initial IntentionsWhenDr.Bowyerfirst
foundedtheRepRapproject,hisintentionsweresimple:todevelopaninexpensiveopen-source3Dprinter,withalong-termgoalofself-replication.Thename“RepRap”isacontractionof“replicatingrapidprototyper.”Theideaisthatthebestwaytogeta3Dprinterintoasmanyhandsaspossibleistodesigna3Dprinterthatcan3Dprintacopyofitself.Ifeachperson
printstwonewprintersforfriends,thespreadwouldbeexponential,andbeforelong,everyonewouldhavesmall-scalemanufacturingattheirfingertips.
Thegoalofself-replicationisalongwayofffromfruition;itisaloftygoal,afterall.Suchadesignwouldhavetobecapableofnotonlyprintingtheplasticframepieces,butalsomotors,
electronics,andothercomplexnonplasticparts.Butthatoptimisticlong-termgoalhasyieldedbountifuldevelopmentsforconsumer3Dprinters.
The Importance ofOpen SourceOneofthecoretenantsoftheRepRapproject,possiblythemostimportantofthem,is
thatitiscompletelyopensource.Everydesignanddevelopmentiscompletelypublic,allowinganyonetousethedesignsandcontributetotheproject.
Anytimeanewbreakthroughismade,itcanbeimmediatelyreleasedandintegratedintothedesignofnewprinters.AgoodexampleofthisistheRepRapArduinoMegaPololuShield
(RAMPS)controlboard,whichisessentiallythebrainofthe3Dprinter.TheRAMPSboardconnectstoanArduino(anotheropen-sourceproject)toprovidecomputercontrolofthe3Dprinter’smotorsandextruder.ThedevelopmentofRAMPSallowedpeopletoquickly,cheaply,andeasilycontroltheir3Dprinters,soitwasquicklyintegratedintothedesignofsubsequentRepRap
printers.
DEFINITIONArduino is an open-
source platform fordeveloping and prototypingelectronics. Arduino modelsare generally small circuitboards without inputs andoutputs for controllingvarious electronics. TheArduino Mega is used by theRAMPS control board for 3Dprinting.
ThesameistrueofanyothernewRepRapdevelopment.Becauseit’sopensource,therearenopatentstodealwith,andthenewdevelopmentcanbefreelyusedandimproved.ThisconcepthasbeenessentialtothesuccessandrapidevolutionofRepRap3Dprinters,andconsumerprintersingeneral.
RapidDevelopmentDuetotheiropen-sourcenature,RepRapprintershaveevolvedextremelyquickly.Thefirstcompletedesign,theDarwin3Dprinter,wasreleasedin2007.Darwinwasaverybasicdesign,wroughtwithlimitationsandcapableofonlymediocre-qualityprinting,butitprovedthat3D
printerscouldbeinexpensiveandbuiltathomebyhobbyists.LikemostsubsequentRepRapprinters,andconsumerprintersingeneral,Darwinutilizedthefusedfilamentfabrication(FFF)3Dprintingprocess.FFFisexactlythesameasFDMinpractice(filamentismeltedandsqueezedoutofanozzleinlines,forminglayers)andwasonlynameddifferentlytoavoidlegal
problemswithStratasys,whopatentedtheFDMprocess.
TheRepRapDarwin,whichwasthefirstdesignreleasedbythe
RepRapproject.
In2009,anewRepRapdesigncalledMendelwasreleased.Itmadeanumberof
improvementstotheDarwindesign,whichincreasedreliabilityandprintqualityanddecreasedthedifficultyofbuildingtheprinter.Mendelintegratedmanydevelopmentsthathadbeenmadebetween2007and2009intoacompletepackage,whichwouldbeacontinuingtrendwithnewdesignsthatfollowed.
BythetimethePrusaMendel
andHuxleyRepRapdesignswerereleasedin2010,thecommunityhadalreadygrowntremendously.Manyoffshootsandderivativesofthestandardmodelsalreadyexisted,makingimprovementsandcustomizationstosuitindividualtastes.Today,thereareatleast30officialRepRapdesigns,withderivativesnumberinginthehundreds.Currentdesigns
rivaltheconsumerprintersbeingreleasedbycompanieslike3DSystemsandStratasys,whoindependentlydevelopedtheirown(closed-source)designs.RepRapprintershaveachievedqualityandreliabilitysohighthatthey’reevenbeingusedinprofessionalprototypingsettings.
FASCINATING FACTRepRap models,
following the convention setby the original Darwin, arenamed after notableevolutionary biologists.However, some derivatives,such as the Prusa Mendel,are named after theirdesigners or names theychose.
Refinement,Availability,and YourWalletThejumpfromexpensiveprofessional3Dprinterstoconsumer3Dprintershappenedastonishinglyquickly.Injustafewyears,
consumer3Dprintingwentfrombeingexperimental,unreliable,anddifficulttosomethingthatcouldfeasiblybetakenadvantageofbytheaveragehobbyist.Sohowdidthatrapidevolutionhappen,andwhatdroveit?ThatwaslargelyduetothedevelopmentpioneeredbytheRepRapproject.
UntiltheRepRapDarwinprovedthatconsumer3D
printerswerefeasible,virtuallyall3Dprinterswereexpensiveprofessionalmachinesmeantforcorporatebuyers.ButwiththesuccessoftheRepRapproject,consumer3Dprintingwassuddenlyoneveryone’smind.
3Dprintermanufacturersspecializingininexpensivemodelsintendedforhomeusebeganpoppinguprapidly.Someofthesemanufacturers
soldprintersbasedonRepRapdesigns,whileothersdevelopedtheirown.However,eventhosethatdevelopedtheirowndidsowithknowledgeandinformationthatoftenoriginatedwiththeRepRapproject.
IntheshorttimesinceDarwinwasreleasedin2007,theconsumer3Dprintermarkethasgrown
exponentially.Priceshavedroppedfromthetensofthousandsofdollarstojustafewhundreddollarsfortheleastexpensiveprinters.Butit’snotjustthepricethathaschanged.Thequalityofavailable3Dprintershasevolvedbyleapsandboundsaswell.JustlikewiththeCambrianExplosion,themarkethasgonefrombeingessentiallynonexistenttobeingahugeanddiverse
ecosystemfullofevolvedandrefined3Dprinters.
Whatdoesthatexplosionof3Dprinterevolutioninrecentyearsmeanforthecurrentmarket?Withsuchashorthistory,youmightexpectthat3Dprintersaren’tquitereadyformainstreamuse,andtoanextentyou’reright.3Dprintinginthehomeisstillprettyexperimental,andit’snotassimpleasprintingona
sheetofpaperwithaninkjetprinter.But3Dprintingisarevolutionaryandexcitingtechnology,andthepaceatwhichit’simprovingisastounding.
Maturation ofTechnology
Nomatterwhattheparticularproductis,youcanbetthatitwillimproveastheassociatedtechnologymatures.Thishasbeenespeciallyevidentsincetheadventofpersonalcomputing.Thefirstpersonalcomputerswerebig,expensive,slow,andweren’tparticularlyuseful.Butthetechnologyimprovedsoquicklythatwithinafewyears,priceshaddroppeddramaticallyandusefulness
hadimprovedexponentially.Ofcourse,nowthetechnologyissogoodthatcomputersareubiquitous.
Asimilarmetamorphosisishappeningwith3Dprintersrightnow.We’realreadypastthe“expensiveanduseless”stagenow,andwe’rewellinto3Dprintingenteringmainstreamuse.Asthetechnologyhasmatured,provenformulasanddesign
principleshavestartedtoemerge.
Intheearlydaysofconsumer3Dprinting,everythingwasstillhighlyexperimental.Engineerswerestilltryingtofigureoutthebestwaytodesignprinters,individualpartswerestillbeingcobbledtogetherfromwhateverwasavailableonthemarket,andprintingmethodsandpracticeswerestillbeing
developed.Nowwe’veenteredastageofrefinement.We’vegotthebasicsdown,thereisasolidknowledgebasewithwhichtoworkfrom,andindustrystandardshavestartedtoform.
Atthispoint,printermanufacturersarenolongertryingtosimplyinventapractical3Dprinter;instead,they’reimprovingthefunctionalityofproven
designs.Inthesamewaythatautomanufacturersrefineexistingenginedesignsratherthaninventingnewengines,3Dprintermanufacturersarenowworkingonrefiningtheirprinterstomakethembetterandmoreuseful.
Availability of PartsAsatechnologymatures,
thereisalsoasignificantincreaseintheavailabilityofpartsspecifictothatindustry.WhenacompanylikeDelldecidestobuildanewlaptop,theydon’tmanufacturealloftheindividualpartsfromscratch.Instead,theypurchaseprocessorsfromIntel,memoryfromCorsair,harddrivesfromSeagate,andsoon.Thesepartsareallstandardized,andDellcanpurchasethemknowing
they’llworktogether.Theycanthenassemblethepartsintoaworkingcomputeroftheirdesign.
FASCINATING FACTJust 10 years ago, in
2004, the most inexpensive3D printers available stillcost about $25,000. Now, in2014, functional 3D printerscan be purchased for as littleas $200. This perfectlyillustrates the effect thatdevelopment and partsavailability has had on 3Dprinter prices.
Thesameprocessistrueinmostindustries.Butuntilrecently,3Dprintingwassonewthatindividualpartssimplyweren’tavailabletoprintermanufacturers.Manufacturerswereforcedtoeitherrepurposepartsusedinotherindustries(whichmaynotbewellsuitedto3Dprinting)ormakethemthemselves(inwhichcase,qualityandcostbecameaproblem).Thelackofparts
availableinthe3Dprintingindustrywasahugefactorinthehighcostsofearlyconsumerprinters.
Butthathasstartedtochange.Manypartsarestartingtobecomeavailabletoprintermanufacturers.JustlikeDellcanorderaprocessorfromIntel,a3Dprintermanufacturercannoworderahotend,controlboard,orheatedbedforuseintheir
printers.Thishasgreatlyreducedthecostsinvolvedindesigningandmanufacturing3Dprintersandhasalsoimprovedquality.
Insteadoftheprintermanufacturerhavingtotryanddesigneachandeveryindividualpartwithmarginalresults,theycannoworderthemfromacompanywhichspecializesinthatindividualpart.E3D,forexample,isa
companythatmakeshotendsfor3Dprinters,andthat’salltheydo.Becauseit’stheirsolefocus,E3Dcanconcentrateonjusttryingtomakethebesthotendsonthemarket.Printermanufacturerscanthenpurchasethosehotendsfortheirprintersandhaveahigh-qualitypartwithoutamassivedesignandmanufacturinginvestment.
AhotendmanufacturedbyE3Dthat’sintendedforuseonavariety
ofprinters.
WithcompanieslikeE3Dproducingpartsspecificallyforthe3Dprintingindustry,thequalityofconsumer3Dprintershasincreasedverynoticeably.Andthatwillonlygetbetterasnewmanufacturersofpartsenterthemarketandcompetitionincreases.
The Race to theLowest PriceThatcompetitionbetweenpartmanufacturers,andthecompetitionbetween3Dprintermanufacturers,hasdonewondersfortheconsumermarket.Competitioninthemarketplacealwaysfuels
progressandinnovation,andthathasbeenparticularlyevidentwith3Dprintersbecauseit’shappenedsofast.IntheshorttimesincetheRepRapprojectwasstarted,alargenumberof3Dprintermanufacturershavesprungup.Virtuallyallofthemhavethesamegoal:toprovideahigh-qualityandeasy-to-useprintertoconsumersatthelowestpricepossible.
Originally,thatlowestpricewasstillprettyhigh.Butaspartsavailabilityhasincreasedanddesignshavematured,thosepriceshavebeenfallinglikearock.3Dprintersarenowunder$350,whenoriginallythecheapestconsumerprinterswerestillthousandsofdollars.
HOT TIPWhile prices are
certainly going to keep goingdown, they’re alreadystarting to level out. So ifyou’ve been waiting topurchase a 3D printer untilprices drop, don’t expectthem to get dramaticallylower (at least not for aworthwhile model).
However,theracetohavethe
lowestpricescanonlygosofarbeforeitlevelsout.Materialsandmanufacturingarealwaysgoingtobeanunavoidableexpensefor3Dprintermanufacturers,andtherewillbeapointwhenit’sjustnotpossibletosellprintersanycheaper.Wemaynotevenbethatfarfromthatpointtoday.
Thegoodnewsisthatjustbecausepricescan’tdrop
anymore,thatdoesn’tmeanprogresscan’tstillbemade.Oncepriceslevelout,thenewracewillbetowardmakingthebestprinteratthatprice.A$500computerthatyoubuytodaywillvastlyoutperforma$500computerfrom10yearsago.Andsomethingsimilarislikelytohappenwith3Dprintersinthefuture.Pricesmightleveloutataroundacouplehundreddollars,butwhatyou
getforthatmoneywillcontinuetogetbetterandbetterastimepasses.
The Least YouNeed to Know
3DprintingwasoriginallyinventedbyCharlesW.Hull.Healsostarted3DSystems,whichremainsoneofthelargest3Dprintermanufacturers.FDM3D
printing—thetechnologyusedonmostconsumer3Dprinters—wasinventedbyScottCrump,whowentontofoundStratasyswithhiswifeLisa.
Theconsumer3DprintermarketwaslargelynonexistentuntiltheRepRapprojectfueledopen-sourcedevelopment.
3Dprinterpriceshavedecreaseddramaticallyasthetechnologyhasmaturedandpartshavebecomeavailable.
Quality,reliability,andeaseofusehavesimultaneouslyimprovedasaresult.
Whilethecostof3Dprintersissuretoloweralittlebitmore,pricesarestartingtolevelout.However,theprintersthemselveswillalmostdefinitelyimproveagreatdealincomingyears.
CHAPTER
3
Manufacturingwith 3D
Printers andCNC Mills
In This Chapter
How3Dprinterswork
TheworkingsofCNCmills
Shouldyouusea3DprinteroraCNCmill?
Whenitcomestorapidprototyping,therearegenerallytwoapproachesthatcanbetaken:3Dprintingandcomputernumericalcontrol(CNC)milling.CNCmilling
isn’tstrictlyconsidered“rapidprototyping,”butthat’smostlyamatterofsemantics.Inpractice,CNCmillscancreate3Dpartsjustlikea3Dprinter,andcanoftendoitmorequicklyandwithgreaterprecision.
However,CNCmillsand3Dprintersdiffergreatlyintheiractualoperation.Essentially,they’retwocompletelydifferentwaysofsolvingthe
sameproblem:howtoquicklycreateafunctionalthree-dimensionalpartfromacomputermodel.3Dprinterssolvethisproblemwithadditivemanufacturing,meaningthe3Dprinterstartswithnothingandaddsmaterialtocreatethepart.Ontheotherhand,CNCmillsusesubtractivemanufacturing,aprocesswhichstartswithablockofmaterialandcutsitaway,
leavingthepartbehind.
Bothprocesseshavetheiradvantagesanddisadvantagesandareusefulindifferentsituations.You’vepurchasedthisbook,soyou’veprobablyalreadydecidedthat3Dprintingisrightforyou.SowhyevendiscussCNCmilling?Forone,highlightingthedifferenceswillhelpyouunderstandhow3Dprintingworksanditsbenefits.The
secondreasonismorepractical:it’softenpossibletoconvertCNCmillsinto3Dprinters,andsomemanufacturersareevenbuildingmultipurposemachinesthatarecapableofbothCNCmillingand3Dprinting.Inthischapter,Itakeyouthroughthefunctionsofboth3DprintersandCNCmillsandhowtheycanbeusefultoyouinthe3Dprintingprocess.
The SimplePrincipleBehind 3DPrinting3Dprintingisanadditivemanufacturingprocess,andhowa3Dprinteroperatesisallaboutlayingdownnewmaterialaspreciselyas
possible.Forvirtuallyall3Dprinterstoday,thisisaccomplishedbybuildingthepartupinaseriesofhorizontallayersstackedontopofeachother.Inconsumer3Dprinting,thoselayersarealmostalwayscreatedbyextrudingmoltenplasticinaprecise2Dcross-sectionofthepart.
Slicing and
Creating Layers forYour ModelTheonethingthatvirtuallyall3Dprintershaveincommon,regardlessoftheparticulartechnologythey’reusing,isthattheyallbuildpartslayerbylayer.Partofthe3Dprintingworkflowistakingthedesired3Dmodel(generallyinSTLformat)andfeedingitintoslicing
software.Thisappropriatelynamedsoftwarethenslicesthat3Dmodelintoaseriesofthinhorizontalcross-sectionsthatwillformthecompletepartwhenstacked.
AscreencaptureofSlic3r,anopen-sourceprogramforslicing
modelsfor3Dprinting.
Thesehorizontalcross-sections(calledlayers)canvaryinthicknessdependingonthehardwareofthe3D
printerbeingusedandthesettingsenteredbytheuser.Forconsumer3Dprinters,thelayerthicknessisgenerallysomewherebetween.10mmand.50mm,althoughitcanbeoutsidethatrangewiththerighthardwareandsettings.
HOT TIPCheck to see if the
manufacturer of a 3D printerhas publishedrecommended layersettings. Manufacturersusually do testing todetermine an optimal layerthickness based on theirhardware. Theserecommended settings willbe a good starting point andwill help you quickly achievehigh-quality prints.
Layerthicknessisoneofthemostrelevantcontributorsinthequalityoftheprintedpart.Thethinnereachlayeris,thehigherthequalityofprint.Theeasiestwaytovisualizethisistopictureitatitsextremes.Ifyouhadamodelwithverythicklayers,say5mm(whichiswayoutsideofwhatactual3Dprinterswillprint),yourprintedpartwouldbeextremelyblocky.Attheotherendofthe
spectrum,amodelprintedwithextremelysmalllayers,like.01mm,wouldyieldavery-high-qualityresult.
Thedifferencebetween5mm(left)and.01mm(right)layerheights.
But,ofcourse,therearelimitationsthatkeepyoufrombeingabletoprintvery
smalllayers.Thehardwareitself,especiallyforconsumerfusedfilamentfabrication(FFF)3Dprinters,haslimitsonhowthinitcanextrudefilament.Evenifthehardwarewascapableofextremelythinlayers,itwouldtakeanimpracticalamountoftimefortheslicingsoftwaretogeneratethelayers.
Themostnoticeablefactor
fortheenduser,however,endsupbeingprinttime.Asthethicknessofthelayersdecreases,thetotalnumberoflayersincreases.Themorelayerstherearetoprint,thelongeritwilltaketheprinttocomplete.Forexample,ifaparticularmodeltakestwohourstoprintwithlayerssetat.4mm,youwouldexpectittotakefourhourswhenthelayerthicknessiscutinhalfto.2mm.Youdoubledthe
numberoflayers,andsothetimetoprintwoulddoubleaswell,right?
Unfortunately,that’snotthecase,andtheprinttimewouldactuallyincreasebyalotmorethanthat.Thereasonforthisisthatthefilamentbeingextrudedhasa3Dprofile,soastheheightdecreases(intheZdirection),itswidth(intheX/Yplane)alsodecreases.Theresultis
thateachlayeritselftakeslongertoprint,inadditiontohavingmorelayerstoprint.
Extruding FilamentFilamentextrusionishowthe3Dprinteractuallycreateseachofthoselayers.InconsumerFFFprinters,theprocessgenerallyworkslikethis:aspooloffilamentisfedintoanextruder(seeChapter
7),whichhasamotoranddrivesystemtopushthefilamentintothehotend.Thehotendthenveryquicklymeltsthefilamentandpushesitthroughasmallnozzle.Theresultisathinthreadofsoftmoltenplasticbeingsquirtedoutofthenozzle.
DEFINITIONThe hot end of a 3D
printer is what heats and
melts the filament that is fedby the extruder assembly.As filament is pushed intothe hot end, a heatingelement heats the hot end.The temperature is hotenough to almost instantlymelt the plastic into a veryviscous fluid, which is thensqueezed out of the nozzleand deposited on the printbed.
Whilethe3Dprinteris
running,thetipofthenozzleisheldveryclosetotheprintbed.Asit’sbeingejectedfromthenozzle,thethreadofplasticstickstotheprintbed.The3Dprintercontinuouslymovesthetipofthenozzlearoundtheprintbed,trailingathreadofplasticbehind,toformasolidlayerofplasticthatmatchesthelayergeneratedbytheslicingsoftware.Theprinterthenmovesthenozzleupslightly
(relativetothebed)andstartsextrudinganewlayerofplasticontopofthepreviouslayer.Thatprocessisrepeateduntilallthelayershavebeenprintedandthepartiscomplete.
Thesizeofthemoltenplasticthreadcomingoutofthenozzle,thedistancebetweenthenozzleandprintbed,andtheamountoffilamentbeingpushedintothehotendare
howthe3Dprintercontrolsthethicknessofthelayerit’sprinting.Thethreadsizeisdirectlyproportionaltothesizeoftheholeinthetipofthenozzle.Solayerthicknesscanbeadjustedbychangingtheseparameters.
Moltenfilamentbeingextrudedtocreatethefirstlayerofapart.
However,asItouchedonintheprevioussection,thelayerthicknessislinkedtotheamountoftimeittakesto
printthelayer.Asthatthreadofmoltenplasticgetsthinner,ittakesmoretimetocreateasolidlayer.Theresultisatrendthatholdstrueinmostaspectsof3Dprinting:thequalityoftheprintedobjectandthetimeittakestoprintarelockedtogether.
CNC Millingand How ItWorksMillingmachinesareastandardtoolinmachineshopsaroundtheworld.Intheirmostbasicform,theyhaveamotorcalledaspindlethatspinsanendmill(whichisverysimilartoadrillbit).
Thematerialtobemilledisattachedtoaplatformthatcanbemovedinthree(ormore)dimensions,relativetotheendmill.Themachinistthenmanuallymovestheplatform(orendmill)aroundusingcontrolmechanisms.Thisallowshimtocutawayatthematerialwiththeendmilltoformthedesiredpart.
FASCINATING FACT
Before the advent ofcomputer numericalcontrol, there was just
numerical control. Numericalcontrol mills relied on acomplex mechanical punchcard system to program themill. These programs took agreat deal of time andexpertise to create, but therepeatability of the programsmade numerical control millsuseful in manufacturingsettings.
CNCmillssimplyremovemanualoperationfromtheequation.Insteadofamachinisthavingtomanipulatethecontrols,acomputercontrolsthemovement.Thewaythecomputercontrolsmovementisactuallyprettysimilartotheway3Dprinterswork:electricmotorsmovetheendmillintheX,Y,andZaxesrelativetotheprintbed.Theprimarydifferencesarethe
subtractivemanufacturingaspectandthematerialsCNCmillscanworkwithcomparedto3Dprinters.Thesimilaritybetweenthethree-axismovementinCNCmillsand3DprintersiswhatmakesitpossibletoconvertaCNCmillintoa3Dprinter.It’salsowhatallowsmanufacturerstomakemachinesthatcanhandlebothtasks.
Subtracting withCAM SoftwareBecauseCNCmillscreateapartbysubtractingmaterial(asopposedtoaddingitlikea3Dprinter),thesoftwareandprocesstheyfollowarecompletelydifferent.While3Dprintersaddmaterialinlayers,CNCmillsstartwithablockofmaterial(orbar,cylinder,andsoondepending
onthestockused)andcutawaymaterialin“pockets.”Theydon’tcutawayalayerattime,butrathercutoutparticularsectionsandfeatures(oftencompletely)beforemovingontootherfeatures.SometimescastmetalpartsareevenusedastheinitialstockandthenarerefinedwithCNCmilling.
Thisiscontrolledwithcomputer-aided
manufacturing(CAM)software.Likeslicingsoftware,CAMsoftwaretakesa3Dmodel(ofteninSTLformat)andprocessesittocreateinstructionsfortheCNCmilltofollow.However,unlikeslicingsoftwarefor3Dprinters,CAMsoftwaregenerallyrequiresmuchmoreoperatorinteraction.Thisisaprofessionuntoitself,becausesettingupaCNC
programrequiresexperienceandskill.
CAMsoftwareservesthesamepurposeasslicingsoftwarebutfollowsverydifferentrules.
HOT TIPThe skill and
experience of the CNC
operator is importantbecause CNC millingtechniques and settings canvary tremendously based onthe shape of the part beingmade, the material it’s cutfrom, the type of end millbeing used, and the desiredsurface finish and quality.For these reasons (amongothers), 3D printers aremore suitable for home use,as the slicing software ismuch simpler to use thanCNC CAM software.
Milling the MaterialWhile3Dprintersaremostlylimitedtoplastic(exceptinexperimentalprintersandveryexpensiveprinters),acommonCNCmilliscapableofcreatingpartsfromavarietyofmaterials.Steel,aluminum,brass,titanium,wood,andmostplastictypesareallpossibletomachineonasuitableCNCmill.Whateverthematerial,CNC
millsstartwithablockofit,andwhateverismillediseitherthrownawayorrecycled.
ThatversatilitymakesCNCmillingusefulformorethanjustrapidprototyping.CNCmillsareveryoftenusedtoactuallymanufactureparts,especiallyaluminumandsteelparts.TheprecisionofCNCmillingalsoallowsittoachieveverytighttolerances
thatarenecessaryforproductionparts.
However,becausemillingisasubtractiveprocess,thematerialthat’scutawayisgenerallywasted.3Dprintersusuallyonlyusethematerialthat’sactuallyneededtocreatethepart(althoughsometimesmoreisusedforsupportstructures).Consideringthehighcostofmaterials,thatcanbea
significantfactorinthepriceofthepart.
Pros andCons of 3DPrinters vs.CNC Mills
3DprintersandCNCmillsarebothversatileanduseful,andeachexcelsatdifferenttasks.Eachhasjobsforwhichthey’rebettersuited,andeachhasjobsforwhichtheywouldbeapoorchoice.Sowhataretheprosandconsofeach?Whenshouldyouuseoneversustheother?
Cost
Themostobviousdifference,foranyonepurchasinga3DprinterorCNCmill,isgoingtobecost.Capableconsumer3Dprinterscanbepurchasedforunder$1,000,whileCNCmillscapableofmachiningmetalslikealuminumandsteelarerarelylessthan$5,000(andareusuallymuchmore).However,lesspowerfulCNCmillscapableofmillingsoftmaterialslikewoodaresignificantlyless
expensive(usuallylessthan$2,000).
Thecostdifferenceismostlyduetotheexpensivehigh-powerelectricmotorneededfortheCNCspindle,thecoolingsystemsneededwhenmillingmetal,andthefactthatCNCmillsrequireaverysolidandrigidframe.3Dprinters,incomparison,requiremuchlessexpensivepartstobuild.
Asidefromthepriceofthemachineitself,thereareothercoststoconsider.CNCmillsrequireendmills,whichneedtobereplacedaftertheybecomeworn.MostCNCoperatorsprefertohavearangeofendmillsaswell,indifferentsizesandshapesfordifferentjobs.3Dprinters,ontheotherhand,generallyonlyrequirethatyourpurchasethematerialitself.
IfyouwantedtoconvertaCNCmilltoa3Dprinter,itisrelativelyinexpensive,generallyonlyafewhundreddollars.
HOT TIPWhile 3D printers don’t
require expensiveconsumable accessories likeend mills, you shouldconsider the cost of filament.Most people end uppurchasing many rolls offilament in a variety of colorsand materials. This expensecan be significant, especiallyfor exotic filament materials.
Part GeometryOneofthebiggestadvantagesthat3Dprintershavetoofferistheirabilitytocreatecomplexgeometry.Therearepartsthatcanbe3Dprintedthatsimplyaren’tpossiblewithtraditionalmanufacturingmethods.Thewaythat3Dprinterscreatepartsinlayersmeansthatinternalgeometrycanbeproducedjustaseasilyas
externalgeometry,aprospectwhichsimplyisn’tpossiblewithanyothermanufacturingmethod.
Aneasy-to-understandexampleofthisisasimplecubewithahollowsphereinthecenter.Noothermanufacturingmethodiscapableofproducingsuchapart,butit’satrivialtaskfora3Dprinter.Practicallyspeaking,it’snotanymore
difficultfora3Dprintertocreateapartlikethatthanitwouldbetocreateasolidcube.
Thiscapabilityunleashesawholeworldofpossibilitiesthatwerepreviouslyconsideredunfeasibleorsimplyimpossible.Youcouldevenprinttwo(ormore)partsthatarealreadyassembled,allowingyoutocreateassemblieswhichwouldn’tbe
possiblewithanyothermanufacturingtool.
Apartthatcouldonlybecreatedbya3Dprinter.
Evenmoretraditionalpartsareeasiertocreatewitha3Dprinter.Partswithfeaturesonallsides,forexample,can’t
bemachinedonastandardthree-axisCNCmillwithoutadditionalwork.Thepartwouldhavetobeturnedovertomachinetheotherside,orafourthaxiswouldhavetobeaddedtothemillforrotatingthepart(whichisafairlyexpensiveaddition).
However,3Dprintersdohavelimitationsonwhatkindofgeometrytheycanhandle(especiallyconsumerFFF
printers).Theselimitationsareusuallyrelatedtooverhangsinthepart,astherealwayshastobesomethingtoprintontopof.Butthatcanbeovercomebyprintingsupportmaterialwhichislaterremoved.
FASCINATING FACT3D printers with two or
more extruders can use oneof the extruders solely for
printing support material.This support material isoften a special kind offilament producedspecifically for this use.Once the print is finished, itcan be soaked in a chemicalbath, which dissolves thesupport material but leavesthe rest of the partuntouched. Such a setupwould be capable ofproducing almost anygeometry imaginable.
Material MattersAsIexplainedintheprevioussections,thematerialCNCmillsarecapableofmachiningisalotmorevariedthanwhat3Dprinterscanprint.3Dprintersintheconsumermarketarelimitedtodifferentkindsofplastics,whileCNCmillscanmachinemostcommonmaterials(withtherightsetup).
Butit’sactuallynotthatsimpleinpractice.Thecostofmaterialiscertainlyaconcern.MachinableblocksofmaterialsuitableforCNCmillingtendtobefairlyexpensiveandhavetobepurchasedorcutinthenecessarysizes.Ifthepartyou’remakingisn’tverycloseinsizetotheblockofmaterial,thechancesaregoodthatalotofmaterialwillgotowaste.
MillingdifferentmaterialsalsorequiresthattheCNCmillbesetupforthatmaterial.Theendmill,coolingsystem,andeventheframeoftheCNCmillitselfneedstobecorrectforthatmaterial.Thisiswhymillsarelessexpensivewhentheyonlyneedtobecapableofcuttingsoftmaterials,andaremoreexpensivewhentheyneedtocuthardmaterialslikesteel.Eachmaterialalso
requiresdifferentmillingsettings,andittakesexperienceandknowledgetoproperlymillavarietyofmaterials.
Incontrast,3Dprintersgenerallyonlyrequirethatyouadjustafewsettings(namelytemperature)whenswitchingbetweenmaterials.Simplyput,3Dprintingismucheasier,andthelearningcurveisshorterthanCNC
milling.CNCmillscertainlyhavetheadvantageofmaterialversatility,butthatversatilityisdifficulttoachieve.
Surface FinishThefinalqualityofapartislargelyaconsequenceofthesurfacefinishonthepart.Thesurfacefinish,inthiscontext,ismostlyabouthowsmooth
thecompletedpartis.Inamanufacturingsetting,surfacefinishhasaslightlydifferentconnotation.Forproductionparts,asmoothsurfaceisn’talwayswhatisdesired.Sometimesit’spreferabletohavearoughfinish,brushedfinish,ormattefinish.Thesearealldifferenttypesofsurfacefinishes,andtherearemanyothers.Noparticulartypeisnecessarilybetter;it’sjusta
matterofwhat’sneededforthepart.
However,inmostcases,themanufacturermustfirststartwithasmoothfinishandthenaddthedesiredsurfacefinish.Ifweuseinjectionmoldedplasticpartsasanexample,thisprocessispartofmakingthemold.Ifatexturedmattefinishisdesiredonthepart,thatfinishhastobeonthesurfaceofthemold.Inthis
case,themoldismilledassmoothlyaspossible,andthenthefinishisaddedafterward(eithermechanicallywithsandingorwithchemicaletching).
Inalmosteverycase,themoldorpartisideallyassmoothaspossibletobeginwith,andthenthesurfacefinishisadded.Thereasonit’sdonethatwayistoavoidimpartingunintendedartifacts
ontothesurface.Andso,you’dwanttobeabletoachieveassmoothofasurfacefinishaspossiblewheninitiallymakingapart.
GettingaverysmoothfinishisusuallyasimplematterwithaCNCmill.ItdoestakeskillontheCNCoperator’spart,andusuallyasmootherfinishtakeslongertomachine,butit’scertainlypossibletogetaverysmooth
finishstraightoffthemill.Unfortunately,thisisn’tthecasewith3Dprinters,andisprobablyoneoftheprimaryreasonsthat3Dprintingisn’tmorecommoninproductionmanufacturing.
AsI’veexplainedpreviously,thenatureof3Dprintingmakesridgesonthesurfacealmostunavoidable.Theway3Dprinterscreatepartsbyaddinglayersvirtually
ensuresthatsmalldifferencesbetweenthoselayerswillbevisible.Very-high-end(non-FFF)3Dprintersusedinprofessionalsettingscanachievesmoothsurfacefinishes,butthosekindsofprintersarefaroutofreachforconsumers.Theirhighcostalsomakesthemimpracticalforanykindofmanufacturing,evenforthecompaniesthatcanaffordthem.
Evenathigh-qualitysettings,a3D-printedparthasarough
surface.
Soisiteverpossibletoachieveasmoothsurfacefinishonaconsumer3D
printer?Luckily,theanswerisyes!Smoothfinisheson3D-printedpartscanbeattainedwithpostprintfinishing.Therearemanytechniquestodothis:everythingfromsimplysandingtheparttomorecomplicatedchemicalmethods.ButthosepostprintfinishingmethodsarestillanadditionalstepthatCNCmillsdon’trequire.
Attheendoftheday,ifyou’relookingforprofessional-lookingpartswithasmoothsurfacefinish,CNCmillsarethebetterchoice.Withoutpostprintfinishing,3D-printedpartswillalwayslookliketheywere3Dprinted.Youcangetaniceandprofessionalfinishona3D-printedpart;itwilljusttakemorework.
Using theRight Toolfor the JobWithallofthesedifferences,howdoyouknowifyoushouldusea3DprinteroraCNCmill?Asalways,it’simportanttochoosetherighttoolforthejob.Justlikeyouwouldn’tuseawoodsawto
cutametalpipe,youdon’twanttousea3DprinterwhenaCNCmillwoulddothejobbetter(andviceversa).Inthiscase,choosingtherighttoolisaboutfirstdeterminingwhatthejobwillbe.
HOT TIPThere are practical
differences which mightaffect your decision as well.For example, CNC mills are
very loud and can be quitemessy. 3D printers,however, are usually fairlyquiet and don’t create muchmess. If you live in anapartment, a CNC mill wouldprobably be pretty disturbingto your neighbors, while a3D printer shouldn’t even benoticeable to them.
Ifyouintendtomakeproductionpartsormoldsforinjection-moldedparts,a
CNCmillisgenerallytheclearchoice.They’restillcapableofcreatingprototypepartsinashortamountoftimebutcanalsoproduceprofessionalpartswithahigh-qualitysurfacefinish.However,theirnoise,mess,andexpensearecertainlyaconcern.
Formosthomeusersandhobbyists,a3Dprinterwillbeeasiertouseandmore
usefulingeneral.Youcancreateawiderangeofpartswithlittleconcernaboutgeometrylimitationsandcomplicatedsettings.Thecostofmaterialislower,youwastelessofit,andthenoiseandmessareminimal.
Intheend,it’seasytoseewhyamachinecapableofbothtaskswouldbesouseful.Theframe,movementmechanics,andcontrolsare
verysimilarbetween3DprintersandCNCmills.SwitchingtheCNCspindleforanextruderallowsyoutodobothCNCmillingand3Dprintingwiththesamebasicmachine.Thisiscertainlymoreexpensivethanadedicated3DprinterorCNCmill,butmuchlessexpensivethanpurchasingoneofeach.
The Least You
Need to Know3Dprinterscreatepartsbybuildinguplayersofmaterial,aprocesscalledadditivemanufacturing.CNCmillsusesubtractivemanufacturing,whichmeanstheycreatepartsbycuttingawaymaterial.
Generallyspeaking,3Dprintersarebetterforthehomeuser,whileCNCmillsmaybeabetterchoicefor
businesses,dependingontheexpecteduse.
CHAPTER
4
Types of 3DPrinters
In This Chapter
Stereolithographyandits
subset,digitallightprocessing
Creatingcolorfulmodelswithpowderbedprinters
PrintingstrongpartswithMultiJetprinters
Meltingparticleswithselectivelasersintering
Thereasonforfusedfilamentfabrication’spopularity
Sofarinthisbook,I’vetalkedabout3Dprintingingenerictermsthatapplyto
most3Dprinters.Butinpractice,notall3Dprintersworkinthesameway.Tomoveforwardwiththisbook,Ineedtopickaparticular3DprintingprocessthatIcandigdeeperinto.
Therearemanykindsof3Dprintingtechnologiesonthemarkettoday,andeachofthemoperatesdifferently.Mostoftheseprocessesareusedspecificallyforacertain
applicationoraparticularmaterial.Idon’thavethespacetocovereveryprocesshere,soinsteadIgooverthemostcommontypesof3Dprintinginusetoday,plustalkaboutwhyfusedfilamentfabrication(FFF)printingisthego-totypeformanyhobbyists.
StereolithographyIfyourecallfromChapter2,thisistheoriginaltypeof3DprintingprocessdevelopedbyCharlesW.Hullandhiscompany3DSystemsinthe’80s.Stereolithography(SLA)worksbyshiningaUVlaserontoavatofUV-curablephotopolymerresin.Thelaserisfocusedontheresintoproducethe2Dcross-
sectionofeachlayeronabuildplatform,andthentheplatformisslightlyloweredinordertoformthenextlayer.
SLA,asidefromhavingtheprovenhistoryofbeingthefirst3Dprintingprocess,hassomekeyadvantageswhichmakeitapopularchoiceeventoday.AnSLAprintercanprintpartswithrelativelysmoothsurfacefinishes
comparedtoothertypesof3Dprinting,withalmostcompletelyunnoticeabledifferencesbetweenlayers.ThisqualityispossiblebecauseofthehighprecisionoftheUVlaser,whichalsoallowsittocreatepartswithinverytighttolerances.
ThequalityandprecisionofSLAprintersmakesthemidealinprofessionalresearchanddevelopmentsituations,
whereprototypepartsneedtoverycloselyresembletheirmass-producedcounterparts.Thesurfacefinishalsohasahigh-enoughqualitythatSLAprintedpartscanbeusedasmastersforcreatingmolds.
However,thequalityofanSLAprintercomesatahighprice.High-endconsumermodelSLAprintershavestartedenteringthemarketrecently,butthey’vemostly
beenusedonlybybusinessesforcreatingprototypes.ThecheapestSLAprintersstartinthethousandsofdollarsandcanbemorethanahundredthousanddollarsforprofessionalmodels.
Asidefromthecostoftheprinteritself,expensiveresinisalsoneededasthematerialtocreateparts.Thisresincancostanywherefrom$80to$200perliter,andismuch
moreexpensivethantheplasticfilamentusedinmostconsumer3Dprinters.ThewaySLAprinterscreatepartsinavatalsomeansthat,forconventionaldesignsatleast,hollowpartswillbefilledwithresin.Thiscanaddtothecostofthematerialandtotheweightofthepart.
Insomecases,theprintedpartrequiresadditionalcuringaswell.Thisisdependenton
theprinterandresinbeingused,butisstillafactor.Curingthepartgenerallyrequiresaseparatedeviceandadditionaltime.
Digital LightProcessingDigitallightprocessing(DLP)3Dprintingisvery
similartoSLAprinting;infact,it’sconsideredasubsetofSLAprinting.DLPprintingworksalmostexactlylikeSLAprinting,withavatofphotopolymerresinthatishardenedlayerbylayer.
TheprimarydifferencebetweenDLPprintingandtraditionalSLAprintingisthemethodusedtoshinelightontotheresin.Ifyou’refamiliarwithvideoprojector
systems,youmayhavealreadyheardofDLPinthecontextofmovieprojects.Thetechnologyisusedtoprojectlight(intheformofimages)ontoascreen.
ThissametechnologycanalsobeusedtocurethelayersofresininaDLP3Dprinter.Insteadofprojectingavideo,aDLPprinterprojectslightintheshapeofeachcross-sectionontheresin.This
allowsaDLP3Dprintertocureanentirelayeratonce,abigadvantageoverthesingle-pointlaserusedinconventionalSLAprinters.
FASCINATING FACTDLP 3D printers are
capable of curing an entirelayer of resin in just a fewseconds. This speed allowsthem to print very quicklycompared to other types ofprinters.
Bycuringanentirelayeratonce,DLPprintersdramaticallyreducethetimeittakestoprintapart.
Additionally,thesize,shape,andcomplexityofeachlayerhavenoeffectonthetimeittakesaprint.Asidefromtheobviousadvantageofbeingabletoprintlargeandcomplexparts,thisalsomeansthatmanyduplicatepartscanallbeprintedatoncewithoutaddinganyprinttimecomparedtoasinglepart.
However,DLP3Dprinters
tendtohavethesamedownsideasstandardSLAprinters:cost.WhilethepriceofresinisusuallyaboutthesameasSLAresin,theprintersthemselvesaremoreexpensive.DLPprojectorsarestillcomplexandexpensivepiecesoftechnology,andaddingthemtoa3Dprinterisnotacheapproposition.
Powder BedPrintingAhandfulofspecificprintingprocessescouldallbeconsideredpowderbedprinting.Allofthesetypesofprintershaveonethingincommon:apowdermaterialisspreadonabed,andaliquidbinderisusedtosolidifyitinlayers.The
differencescomefromthefollowing:
Thetypeofpowdermaterialused
Thetypeofbinderused
Themethodusedtoinjectthebinderintothepowder
Thetypesofpowderandbinderusedcanvarybasedonneed,andhaveevolvedovertheyearssincepowerbedprintingwasinvented.Itcan
beanythingfromsimpleplasterpowderthatissolidifiedbyinjectingwater(liketheoriginalbinderjettingprocessdevelopedatMITandsoldbyZCorp.)toadvancedresinorepoxycombinationsthatreplicatecommonengineeringmaterials.
Oneofthemostcommonandpopularofthesepowderbedprintersonthemarkettoday
istheinkjettype.Theyuseaprintheadsimilartowhatisusedincommonhouseholdinkjetprinters,butinsteadofprintingink,theyprintabinderontothepowder.
Therearetwoprimaryadvantagesthatpowderbedinkjetprintershaveoverothertypesofprinters:supportmaterialisn’tnecessary,andtheyhavethecapabilityofprintingmulticolorparts.
Theydon’tneedadditionalsupportmaterialbecausethepowderitselfcansupportoverhangswhilethepartisbeingprinted.
Theleftoverpowdercanbereused,sonotmuchmaterialiswasted.However,cleaningthepowderoffthepartisn’tasmalljob.Itcanbeatime-consumingtask,sometimesmadeevenmoredifficultbythefragilityofthepart
producedbysomeprinters(anddependingonthematerial).Removingthepowderwithoutdamagingthepartinthosecasestakesfinesseandcare,buttheothermajorbenefitscanmakethatinconvenienceworthwhile.
Byusingmultipleinkjetsintheprinthead,eachwithadifferent-colorbinder,partscanbeprintedinmultiplecolors.Colorscanevenbe
combined,similarlytoinkjetprintingonpaper,tocreateawidespectrumofcolors.
Theabilitytohandleoverhangswitheaseandtoprintcolorfulpartshasmadepowderbedinkjetprintersverypopularforcreatingarchitecturalmodels.Usageforarchitecturalmodelsisalsoaresultoftherelativeeaseofbuildinglargepowderbedprinters,whicharen’t
limitedtosmallsizeslikeothertechnologies.Thisallowsarchitecturefirmstoprintlargefull-colormodelsoftheirbuildingdesignsforpresentationpurposes.
Mostpowderbedprintershaveamajordownsidethough,whichisthatprintstendtobebrittleandweak(thoughthisproblemhaslargelybeensolvedwithnewermaterialsand
processes).Thisoftennecessitatestheuseofadditionalpostprinttreatmentsjusttomakethepartsuitableforhandling.Thepowderbedalsointroducesthesameproblemthatiscommonwithprintersthatusevatsofresin:youcan’tprintahollowpartwithoutawayofremovingtheunusedmaterialinsidebeforeit’scompletelysealed.
MultiJetPrintingMultiJetPrinting(MJP),alsocalledPolyJetPrinting,isanother3Dprintertechnologythatusesaninkjet-styleprintheadandcanprintinmultiplecolors.Butunlikepowderbedprinters,MJPprintersdon’tusepowderbeds;instead,theyprintUV-curableresin
directlyontotheprintbed.MJPprintersaddaUVlighttotheprinthead,whichinstantlycuresthephotopolymerresinasit’sdeposited.
HOT TIPMultiJet Printing and
PolyJet Printing areexamples of differentcompanies using similartechnologies under differentnames. MultiJet Printing is
used by 3D Systems, whileStratasys uses PolyJetPrinting. Both work inapproximately the same waybut use different names fortrademark, patent, ormarketing reasons. Whenlooking at 3D printers, keepin mind that the same typeof printer can go by multiplenames.
Becausetheyuseresininsteadofpowder,MJPand
PolyJetprinterscanproducestrongandusableparts.Thisgivesthemadistinctadvantageoverpowderbedprinters,whichproducerelativelyweakparts.
MJPprintershandleoverhangsbyprintingagelsupportmaterialwherenecessary.Thesupportmaterialcanbeeasilywashedawaywithoutdamagingthepart,makingthesupport
removalprocesseasierandfasterthanmoretraditionalapproaches.
ThedisadvantagesofMJPandPolyJetprintersarethecostoftheprinteritselfandthecostoftheresin.Theresincostisonparwiththeresinusedinothertypesofprinters.However,toprintinmultiplecolorsormaterials,differenttypesofresinarerequired.Inthelongterm,
thisshouldn’taddanysignificantcost,becausethetotalamountofresinbeingusedshouldberoughlythesame.Butintheshortterm,itcanbealargeupfrontcosttogetoutfittedwitharangeofresintypes.
Theprintersthemselvesarepricedsimilarlytootherprofessional3Dprinters,whichofcoursearestilltooexpensiveformost
consumers.Beinganewtechnology,MJPprintershaven’tyetmaturedenoughtoreachmoreaffordablepricesthatwouldallowthemtobepurchasedforhomeuse.
SelectiveLaserSintering
Selectivelasersintering(SLS),directmetallasersintering(DMLS),andselectivelasermelting(SLM)allworkinbasicallythesameway.Theyusehigh-powerlaserstoactually“sinter”ormeltpowderedparticlestogetherintoasolidmass.
Likepowerbedinkjetprinters,theyuseacontainerthatisfilledwithpowderlayerafterlayer.Afteranew
layerofpowderisadded,thelaserheatsthepartcross-sectionandthenmovesontothenextlayer.Asusual,theprocessisrepeateduntilthepartisfinished.
However,unlikeotherpowderbedprintingmethods,SLSprintingdoesn’trequireanykindofbinder.Thatmeansanymaterialthatcanbepowderedandmeltedorsinteredwithalasercanbe
used,suchasvariousmetals,ceramics,plastics,andevengreensand.
DEFINITIONGreen sand is a
specially formulated materialused for sand casting. Sandcasting is used to producemetal parts by pouringmolten metal into a moldmade of sand. The mold isnormally produced byforming it around a positive
master part; however, 3Dprinting the mold removesthe need to first create amaster part.
Thesearetheonlycommonlyused3Dprinterscapableofprintingmetalparts,whichgivesthemanobviousadvantage.Insomecases,theprintedpartscanevenbeasstrongasanidenticalpartmanufacturedbytraditional
means.ThismakesSLS-createdpartsparticularlyuniqueandespeciallyuseful.
Unfortunately,SLS,DMLS,andSLM3Dprintersareallveryexpensiveatthispoint,tothepointthatthey’remostlyonlyusedinahandfulofindustriesthatrequirethespecificcapabilitiestheyoffer.Inmostcases,acapablemultiaxisCNCmillismoreeconomicalthananSLS
printer,socompaniesthatpurchasethemdon’tusuallydosowithoutastrongnecessity.
FusedFilamentFabricationAllofthetechnologiesI’ve
talkedaboutsofarinthischapterhavebeentooexpensiveortoospecializedforconsumeruse.Sowhatprocessareyoulikelytouseathome?That’swherefusedfilamentfabrication(FFF)comesin.Thisprocesstakesastringofthermoplastic(calledfilament),meltsit,anddepositsitontotheprintbed.
FFFprintersarehighlyeconomical,makingthem
popularforconsumeruse.Theaffordabilityoftheprintersthemselvesisdueprimarilytothelowcostoftheindividualpartswhichmakeuptheprinterandthefactthattheydon’tneedtobepreciselybuilttofunctionwell.MostoftheotherprintertypesI’vediscussedaredifficulttobuildandhavetobefinelytunedtoproducegoodresults.
Ontheotherhand,FFFprinterscanbebuiltinagaragewithcommonhandtoolsandstillprintwell.Mechanicallyspeaking,they’realsorelativelysimpleandeasytounderstand.Nocomplexlaseroropticalsystemsareneeded,becausetheyoperateonmechanicalprinciples.
Ifyou’veeverusedahotgluegun,youcanprobably
understandhowanFFF3Dprinterworks.Thefilamentiscomparabletothegluestick,thehotendissimilartotheheatednozzleofthegluegun,andtheextruderworkslikethetriggersystemthatpushesthegluestickintothehotnozzle(althoughextrudersworkwithcontinuousrotation).
TheFFF3Dprinterprocess,then,islikeusingahotglue
guntodrawasquare,andthenanothersquareontopofthatone,andthenanothersquareonthatone,andsoon.The3Dprinterisdoingitmuchmorepreciselythanyoucouldbyhand,ofcourse,andit’sdoingitwithplastic,butthegeneralideaisthesame.
WhiletheaffordabilityofFFF3Dprintersmakesthemidealforconsumeruse,the
technologyisusedforprofessional3Dprintersaswell.Professionalversionsworkinexactlythesamewayasconsumermodels,justwithgreaterprecisionandsometimeswithadditionalfeaturesadded.
Thecostadvantagedoesn’tstopattheprinteritselfeither.ThefilamentusedinFFFprintersisthemostinexpensivematerial
availableforany3Dprinteroutthere.Thisispartiallyduetothelow-technatureofthefilament,butit’salsoaresultofthecompetitionintheconsumermarketdrivingpricesdown.ThepopularityofFFFprintershasalsoensuredrapiddevelopmentofboththeprintersthemselvesandthefilamentusedwiththem.
WhileFFFprintersare
popularmostlybecausethey’reaffordableandeasytounderstand,unfortunately,theyprobablyyieldthelowest-qualityprintsofanyofthe3Dprintertypesdiscussedinthischapter.Thefilamentextrusionmethodoflayeringplasticisinherentlyimprecise.And,whileagreatdealofeffortisbeingputintoimprovingthequality,FFFprintersstilllagbehindtheothers.
HOT TIPWhile the quality is
lower than other printers,FFF printers can print arange of thermoplastics.Many of thosethermoplastics are popularfor engineering workbecause of their superiormechanical properties. Partsprinted with materials likeABS and nylon are verystrong, and are usable assoon as they’re finishedprinting.
AnotherdownsideisthetimeittakesanFFFprintertocreateapart.Becauseoftheweightbeingmovedaround,FFFprinterscanonlyacceleratesofast.Thismakessmallfeaturesslowertoprint.Becausetheplasticismeltedasit’sbeingdeposited,it’salsonecessaryforittocoolbeforeprintinganotherlayerontopofit.Mostofthetime,
it’salreadycoolbythetimethenextlayerisprinted.Butifthelayersareverysmall,anFFF3Dprinterwilleitherneedtopausebetweenlayersorriskdeformingthepartduetotheheat.
ThatheatalsoprovidestheunderlyingcauseofthesinglebiggestdisadvantageofFFFprinters:warping.Becausethermoplasticsexpandandcontractasthey’reheatedand
cooled,thepartactuallychangesshapeslightlyasit’sbeingprinted.Ifsomelayerscoolbeforetheothers,thiswillresultinthepartwarpingorevencracking.
AnFFF-printedpartshowingwarpingandcracking.
Howextremethiswarpingisdependsontheparticularthermoplasticbeingused.Acrylonitrilebutadiene
styrene(ABS),forexample,isespeciallypronetowarpingandcracking.Othermaterialsminimizewarping,butnoneofthemseemtobeabletoavoiditentirely.
Printermanufacturers,inanefforttoavoidwarpingandcrackingissues,haveintroducedanumberofwaystotryandcontrolit—heatedbeds,enclosures,andheatedprintchambers.
Thesemethodsaremostlyrelatedtomanagingthetemperatureoftheparttotryandkeepitconsistentthroughouttheprint.Theseworkfairlywellandalmostcompletelyeliminatetheprobleminsomematerials.Rightnow,however,itstillcan’tbeavoidedentirely.
FASCINATING FACTSome of the methods
of reducing warping, such asheated build chambers, arepatented technology. Thismeans that small 3D printermanufacturers can’t usethose methods withoutmaking a deal with thepatent owner. This is part ofthe reason that some of thefeatures seen onprofessional 3D printersaren’t available on consumerprinters.
Thoughwarpingproblemsandrelativelylowprintqualityarecertainlyconsiderabledisadvantages,thereisnodenyingthelowcostofFFF3Dprinters.Theyarebyfarthemostpopulartypeof3Dprinterontheconsumermarket,andvirtuallyallprintersinusebyhobbyistandhomeuserstodayareFDM/FFF3Dprinters.Therefore,it’sextremelylikelythatthiswill
bethetypeofprinteryou’llbepurchasing.
Forthatreason,throughouttherestofthebook,I’llbetalkingabout3DprintinginthecontextofFFF3Dprinting.Manyoftheprinciplesapplytoothertypesof3Dprintingaswell,buttheFFFprocessiswhatI’llbefocusingon.
The Least You
Need to KnowTherearemanytypesof3Dprintersonthemarket,eachwiththeirownadvantagesanddisadvantages.
WhileSLA,DLP,powderbed,MJP,andSLSprintersprinthigh-qualityparts,theircostkeepsmanyhobbyistsfrombuyingthem.
FFF3Dprintersarethemostpopularforconsumerusebecauseoftheiraffordability.
PART
2
All Aboutthe
Hardware3Dprintersarecomplicatedmachines,whichiswhyI’m
devotingthisparttoexplaininghowallofthathardwareactuallyworks.Notonlydoesunderstandingthehardwarehelpyouunderstandhow3Dprintingworks,butitalsogivesyoutheknowledgenecessarytotroubleshootanyproblemsyoumayruninto.Youalsolearnhowbesttoprepareyour3Dprinterforsuccessfulprints.
CHAPTER
5
The FrameIn This Chapter
Cartesian-layout3Dprinters
Theimportanceofframerigidity
Choosingtheright-sizeprinterforyou
Theframeofa3Dprinteriswhateverythingelseisbuilton,makingitaveryimportantfactorinthequalityofyourprints.Printersarebuiltinavarietyofdifferentways,andallthedifferentlayoutsandconstructionmaterialsmakeadifference.Tounderstandwhy,it’sbesttostartbylearninghow3D
printerframesaregenerallyconstructed.
Inthischapter,IgoovertheCartesianlayoutof3Dprinters,constructiontechniquesforthem,andtheimportanceofsizewhenitcomestoyour3Dprinter.
Cartesian
LayoutsWhenitcomesto3Dprinters,layoutreferstothewaytheprinterisdesignedtomoveinthree-dimensionalspace.Thatmovementcanbeachievedindifferentways,butthemostcommonofthoseistheCartesianstyle.TheseprintersarenamedaftertheCartesiancoordinatesystem,whichisthemostbasicway
todefineapointin3Dspace.Thiscoordinatesystemiswhatyouprobablyrememberusinginyourmathclassesinschool:apointisdefinedbyitsXcoordinateandYcoordinateona2Dplane.With3DCartesiancoordinatesystems,you’resimplyaddinganotheraxis(Z)todefinetheverticalpositionofthepoint.
DEFINITIONCartesian is an
adjective used to describethings related to RenéDescartes, who was aFrench mathematician andphilosopher. His manycontributions to mathematicswere the reason for theCartesian coordinate systembeing named for him (thoughhe wasn’t solely responsiblefor its development).
Cartesian3Dprintersusethesamebasicprincipletomovethetipofthehotendtoaspecificpoint.TheyhavemechanismstomoveintheXaxis,Yaxis,andZaxis,allowingthemtopositionthehotendanywherein3Dspace.Forexample,ifthehotendneedstomovefromthepoint[10,10,10](X,Y,Z)to[20,5,10],it’sasimplematterofmovingtheXaxis10unitsinthepositive
directionandtheYaxis5unitsinthenegativedirection.
3DprinterswithCartesianlayoutsarebyfarthemostcommon,bothintheconsumermarketandtheprofessionalmarket,mostlikelyduetothesimplicityofthemathinvolvedincontrollingtheirmovement.Othertypesoflayouts,likeDeltaprinters,requiretheuse
oftrigonometrytoadjustforasimplemoveonasingleaxis.CartesianprintersalsoseemtobeeasierforpeopletounderstandbecausetheymirrortheCartesiancoordinatesystemsusedinCADprograms(seeChapter15).
Ways Cartesian 3DPrinters AreConstructedDespitethesimplicityofthewayCartesian3Dprintershandlepositioning,theiractualconstructioncanbequitevaried.TheX,Y,andZmovementisonlyhowthehotendmovesrelativetotheprintbed.Thepartsthatare
actuallyphysicallymovingcanbecompletelydifferentbetweenprinters.One3DprintermodelmighthavetheprintbedmoveintheXandYdirections,andthehotendmoveintheZdirection.AnotherprintermighthavetheprintbedmoveintheYdirection,andthehotendmoveintheXandZdirections.
This3DprinterhasabedthatmovesintheYaxisandan
extrudercarriagethatmovesintheXandZaxes.
Themostcommonsetuprightnowseemstobetohavethe
printbedmovinginonedirection(eitherXorY)andthehotendmovinginZandtheotherdirection(eitherXorY).Butthisisbynomeansarule,andit’snotevennecessarilythebestmethod.That’smostlybecausewhat’sbestdependsonyourprioritiesandwhatyou’retryingtoachieve.
Cartesian Layout
ConsiderationsSowhydo3DprintermanufacturersusedifferentCartesianlayouts?Shoulditevenmattertoyou?Theshortanswertothefirstquestionisthatone3Dprintermanufacturermightbetryingtoachievesomethingdifferentthananothermanufacturer.Theparticularlayouttheychoosetousecanaffectthecostoftheprinter,
thequalityoftheprints,thespeedatwhichitcanprint,theoverallsizeoftheprinter,andthedifficultyofbuildingit.
Costisusuallythemostobviousofthefactors,andit’scertainlynoticeabletoboththemanufacturerandthecustomer.Thecostvariesbetweendifferentsetupsbecauseofthematerialsneededandhowpowerfulthe
motorsneedtobe.Ifallofyourmovementisdonebythehotendwhiletheprintbedstaysstationary,theZaxismotorswillneedtobeverypowerfulinordertolifttheweightofallthecomponentsoftheXandYaxes.Andofcourse,ifaparticularlayoutusesmorematerialinitsconstruction,itwillcostmore.
Thequalityoftheprintsand
thespeedatwhichtheprintercanprintarealsoinherentlyinterrelated.Generallyspeaking,printspeedislimitedbyprintquality.Mostprintersarecapableofphysicallymovingmuchfasterthantheyactuallyprint.It’samatterofhowfastaprintercanmovewhilemaintainingacceptableprintquality.Thesetwothingsarelargelydeterminedbytheamountofmassbeingmoved
andhowwelltheframeoftheprintercanhandlethestressofthatmass.
Printqualityisaffectedbymovingmassbecauseofsimpleinertia.Ifyourememberyourphysicslessons,you’llrecallthatinertiaincreasesproportionallywithmass.Inertiaistheresistanceofamasstochangeinitscurrentstateofmotion.Thereason
thisaffectsprintqualityisprettystraightforward:ifyou’reprintinginonedirectionandneedtochangedirection(forexample,whenyoureachacorner),inertiawillresistthatchange.Andbecauseinertiaisrelatedtomass,thatchangeindirectionwillbemoredifficultasmoremassisadded.Sotheprinterwillhaveatendencytoovershootthecorner,resultinginpoorprintquality
onthatcorner.
Thisiswhyspeedisasignificantfactoraswell.Ifthemovingmassishighonthataxis,theprintermaynotbeabletoturnthatcornerquicklyathighspeed.Butatlowerspeeds,theeffectwillbereduced,resultinginbetterprintquality.Thelessonhereisthatyoucanprintatfasterspeedsasmovingmassisloweredwhilemaintaining
thesameprintquality.
FASCINATING FACTBacklash (an
undesirable delay inmovement during directionchanges) producessomewhat similar effects tothose caused by poorrigidity, but is a separatephenomenon with a differentcause. Backlash is causedby looseness in theinterfacing parts of the linear
movement systems used on3D printers. When thatlooseness is present, thereis a small delay before thesystem is engaged when thedirection of an axis’smovement is changed.
Butwhatdoesthathavetodowiththeparticularlayoutusedforagiven3Dprinter?Itmeansthatprintermanufacturerstrytoreduce
themovingmassontheXandYaxes,whichiswhythatmovementisoftendividedbetweenthehotendandtheprintbed.Thatway,theoneaxisonlyhasthemassandinertiaoftheextrudertodealwith,whiletheotheraxisonlyhastohandlethemassandinertiaoftheprintbed.Thisallowsyouprintathigherspeedswhilemaintaininganacceptableprintquality.
Thesizeoftheprinterisalsodirectlyaffectedbythelayoutchosen,especiallywhenyouconsiderthetotalareaneededbytheprinterwhentheprintbedmoves.IftheprintbedweretomoveinboththeXandYdirections,theprinterwouldneedfourtimestheareaofacompletelystationarybed.Thisissimplybecauseeachaxiswouldneedtobetwiceaslongasthebedinorderforthenozzleto
reacheverypointonthebed.Soifthegoalistoproduceaverycompact3Dprinterthattakesupverylittledeskspace,astationarybedwithallmovementdonebythehotendwouldbeideal.Ofcourse,thatwouldleadtoalotofmovingmass,andpotentialprintspeedswouldbelower.
ThesizedifferencebetweenaPrintrbotSimple(left)andaLulzBotTAZ4(right).Note,
however,thatthePrintrbothasa6×6-inchbed,whiletheLulzBot
hasa12×12-inchbed.
Howallofthisaffectsthedifficultyofactuallybuildingtheprintershouldbereadilyapparent.Themorecomplexthedesignofa3Dprinter,thelongeritwillittakethemanufacturertoassembleit(oryou,ifyoubuyakit).Betweenthisandallofthefactorsinvolved,it’sobviousthat3Dprintermanufacturershavealottoconsiderwhendesigningaprinter.
Butshouldyoubeconcernedwithwhatlayoutaparticularmodeluses?Itdoesmatter,forthereasonsI’vegoneoverinthissection.Butit’sdifficulttodeterminereal-worldresultsbasedonthelayoutalone.That’sbecausethingsliketheinertiaandmomentumcanbecounteracted,andoneofthebestwaystodothatiswithahigh-qualityframe.
TheImportanceof FrameConstructionHowthe3Dprinterisactuallyconstructedisoneofthemostimportantfactorswhenitcomestoprintqualityandreliability.Everyother
partoftheprintercouldbeperfect,butiftheframeispoorlyconstructed,theresultswillbeverypoor.
A3Dprinterframedoesn’tjustneedtoholdtheotherpartstogether;italsohastokeepthemstableandaligned.Ithastoholduptotheforcesofmomentumandinertiacausedbythemassbeingmovedaroundtheprinter’saxes,aswellaskeeptheaxes
properlyalignedatalltimesandmaintainthecalibrationoftheprinterunderthestressofconstantmovementandvibration.
Rigidity and How ItAffects Quality andReliabilityThesinglemostimportantcharacteristicofa3Dprinter
frameisrigidity.Flexibilityintheframeisthebiggestenemyofprintquality.Ifthereisanyflexintheframe,themomentumofthemovingpartswillresultinpoorprintquality,unlessyouprintatslowspeeds.
Reliabilityisalsoaffectedbytherigidityoftheframe.3Dprintersrequirecalibrationinordertoproducehigh-qualityprints.Calibrationinvolves,
amongotherthings,settingaZheightina“Goldilockszone.”IftheZheightistoohigh,thefirstlayerwon’tadhereproperlytotheprintbed;ifit’stoolow,youwon’tbeabletoextrudeacleanandsolidline.
TheacceptablerangeforZheightisverysmall;usually,itneedstobewithin1/20ofamillimeterforgoodresults.AZheightoutsideofthatrange
willresultinfailedorpoor-qualityprints.TokeepfromhavingtofrequentlycalibratetheZheight,a3Dprintershouldbecapableofmaintainingyourcalibrationforalongtime.AflexibleorlooseframewillcauseyourZstop,Zaxiscomponents,orhotendtomoveslightlyovertime.Thatslightmovementmeansthatyouwillhavetoconstantlyrecalibrateyourprintertocontinuetoget
goodresults.
What Makes aGood FrameSoyounowknowwhyit’simportantfortheframetoberigid,butwhatmakesahigh-qualityandsolidframe?Rigidframeshaveafewcharacteristicsincommon:
Thedesignoftheframe
structure:3Dprinterframestructuredesignisafairlycomplexsubject.Becauseofthecomplexityinvolvedindesigningaframestructureoptimizedforrigidity,alotof3Dprintermanufacturerstaketheoverkillapproachbyusingheavy-dutymaterialsfortheframe.Thebestwaytobesureyouhavethemostrigidframepossibleistomakeitfullyboxed,witheachframepiececonnectedat
bothendstoanotherpartoftheframe.Othermoreunconventionaldesignscanstillyieldgoodresults,butdifficultyofengineeringthemmakesthemlesscommon.
HOT TIPYour intuition might be
your best tool when it comesto determining the quality ofthe frame. Ideally, you wantto actually get your hands onthe printer and see how itfeels. If you can flex it withyour hands, it’s probably nota good choice. But even justlooking at it should give youa good idea: if it looks niceand sturdy, it probably is.
Theconnectionsbetweenframecomponents:Eventhemostingeniousframedesignisgoingtofailiftheframeisheldtogetherwithducttape.Framepiecesshouldbeconnectedtogetherwithastrongmaterialthatresistsflex,whiletheconnectionsthemselvesshouldbedesignedtoresistmovementinalldirections.Asimpleflatsheetmetal90-degreeconnectorwilldoagreatjob
ofresistingflexandmovementparalleltoitsplanebutwilldoapoorjobwhenaperpendicularforceisappliedtothatplane.Toresistforcesinalldirections,connectorsshouldbe3Dinsteadofflat.Or,ifflatconnectorsareused,twoshouldbeusedtogetherinaperpendicularorientation.
Theframematerial:Inessence:strongmaterialsare
good.Metalisbetterthanwood.Steelisstronger(butheavier)thanaluminum.Plasticcouldbeokayifit’sahigh-qualityplasticandtheframeiswelldesigned.
Thebestpossibleperformancewouldbeachievedwithabig,heavy,cast-ironframe.Thesearethekindsofframesusedinheavy-dutymachinetools,becausethey’reincredibly
rigidandstrong.However,theweightandcostmakethemprettyimpracticalforusein3Dprinters(especiallyforconsumerdesktopprinters).
Asafeandcommonframematerialisstandardt-slotaluminumextrusion.Thisisahigh-qualitystructuralmaterialusedinavarietyofindustries.It’spopularin3Dprinterconstructionbecause
it’sfairlyinexpensive,easytofindinallkindsofsizes,easytoworkwithandtoconnectpartsto,andprettystrongforitsweight.
T-slotaluminumextrusionisaveryversatileconstructionmaterialusedinawidevarietyof
applications,including3Dprinterframeslikethisone.
HOT TIPT-slot aluminum
extrusion comes in a varietyof sizes and shapes. 3Dprinters commonly use thevery popular 20×20mm size,which is adequate for theapplication. But bigger wouldbe even better to increasethe strength of each piece ofextrusion (assuming theoverall design is the same).
Woodisalsousedprettyfrequently,mostlybecauseit’scheapandeasytolasercutandworkwith.However,woodprobablyisn’tthebestmaterialtousein3Dprinting.It’shardtoachieveandmaintaindimensionalaccuracyinwoodparts,especiallybecausetheycanexpandorcontractinthepresenceofmoisture.Woodalsotendstobeatleastsomewhatflexible,which,as
youknowbynow,isabadthing.
Plasticandsheetmetalframescanbothbeacceptableaslongasthey’rewelldesigned.Theyshouldbefullyboxedandpreferablyreinforced.Plasticframesshouldbemadefromasturdyandrigidplastic,makingacrylicapopularchoice.
Size MattersNowthatIhaveallofthatdenseengineeringstuffoutoftheway,Icanmoveontoamorestraightforwardtopic:thesizeoftheprinteritself.
Thereisnodenyingthebenefitofalarge3Dprinter.Thebiggertheprinter,thebiggerthepartsyoucanprint.Havingtheabilitytoprintlargeobjectsiscertainly
useful.However,thesizeofa3Dprinterinfluencesmorethanjustthesizeoftheobjectsyoucanprint.
Thelargeraprintergets,themoreit’sgoingtocost.Thisispartiallybecauseoftheobviousmaterialincrease,butthat’snottheonlyreason.Biggerprintersmeanmoremass,whichmeansmorepowerfulmotorsareneededformovement.That
additionalmassalsomeanstheframeneedstobestrongertoresistflex.Thelongersmoothrods(seeChapter6formoreonsmoothrods)alsoneedtobethickersotheydon’tsag.
Thosepowerfulmotorsandalargerheatedbedarealsogoingtoneedmorepower.Notonlydoesthatmeanyouneedabiggerpowersupplytofeedthem,butitalsomeans
youmayneedspecialcontrolelectronicsthatcanhandletheload.
Putthatalltogether,andtherearealotofcostsassociatedwithincreasingthesizeofa3Dprinter.Subsequently,sizeusuallyendsupbeingthesinglebiggestfactorinthepriceofconsumerFFF3Dprinters.
Ofcourse,pricemightnotbetheonlydownsidetolarge3D
printers.Dependingonhowmuchspaceyouhaveavailable,youjustmightnothaveenoughroomforabig3Dprinter.Asmallprinterthatsitscomfortablyonthecornerofyourdeskmightbemoresuitable.
Inordertofigureoutwhatsizeprinteryouneed,youshouldaskyourselfwhatsizeobjectsyou’relikelytoprint.Bigpartscantakeaverylong
timetoprint,usealotofmaterial,andincreaseyourchancesofsomekindofprintfailureduringtheprint—thereisnothingworsethana24-hourprintgettingruined1hourbeforecompletion.Buttheusefulnessofalargeprintareaishardtodeny.Theabilitytoprintlargepartswhenneededisveryhandy,anditwillbeequallycapableofprintingsmallpartstherestofthetime.
HOT TIPNo matter what size
printer you’re looking at,make sure the frame is niceand sturdy. Pay attention tothe layout and look for anypotential flaws, like the printbed or hot end moving onboth axes. Look at theprinter as whole, not just theindividual components, todetermine its quality.
The Least YouNeed to Know
Cartesian3DprintershavemechanismstomoveintheXaxis,Yaxis,andZaxis,allowingthemtopositionthehotendanywherein3Dspace.
Rigidityisveryimportantin3Dprinterdesign.Frameswithflexwillhavepoorprintqualityorwillonlybeabletoprintslowly.
Thelargertheprinter,thebiggerthepartsyoucanprint.However,largerprinterstendtocostmore.
CHAPTER
6
MovementComponentsIn This Chapter
Howlinearmotionworksin
3DprintersUsingsteppermotorsforprecisemovement
Howthreadedrodsmake3Dprintersmoreaffordable
Basicconnectioncomponents
Theframeofa3Dprinteristhefoundationforeveryotherpart,whichmakesitveryimportant.Buteventhebestframeintheworldisuselesswithoutsomekindof
mechanicalsystemformovement.Thegoalforall3Dprintersistoprovidelinearmovementoneachaxis.Thespecificwaythisisaccomplishedcanvarybasedontheparticularprinter,butmostusethesamefundamentalpartsandsystems.
Inthischapter,Igooverthepiecesthataccomplishthemovementneededwitha3D
printer.
Componentsfor SmoothLinearMotionWithanykindoflinearmotionsystem,it’simportant
thatthemotionbeconstrainedtoasingleaxisinonedimension.Anykindofmovementoutsideofthatonedimensionisalmostalwaysconsideredtobeundesirable,becauseitintroducesunintendedmovementintheotheraxes.
Furthermore,themotiononthatoneaxisshouldbeassmoothandfrictionlessaspossible.Thelessfriction
thereisinthesystem,thelessforceisrequiredformovementonthataxis.Frictioninthesystemincreasesthepowerrequiredformotiononthataxisandcancreateinconsistenciesinthemovement.
Forsmoothlinearmotion,regardlessoftheparticularmachine,themostcommonsetupisasmoothrodorrailwithbearingsonthemoving
part.Thisworksinexactlythewaythatyouwouldexpect:thebearingsreducefrictioninthemovement,andtherodorrailgivesthebearingasmoothandstraightsurfacetorideon.Theconceptissimple,buttheindividualcomponentsarestillimportant.
SmoothrodsandsolidbearingsonaLulzbotTAZ4.
Rails and SmoothRods
Smoothrodsareexactlywhattheysoundlike:astraightcylindricalmetalrodthatispolishedsmooth.Railsaresimilar,excepttheydon’tneedtobecylindricalandcanbeflatinstead.Railsareoftenusedwhentheyneedtoprovidesomelevelofstructuralsupport,whilerodsgenerallyaren’tusedaspartofthestructure.However,rodshavetheadvantageofconstrainingmovementin
twodirectionswithasinglebearing,whilerailsoftenneedtwoorthreebearingstodothesame.
FASCINATING FACTIn some 3D printer
designs, the aluminumextrusion that makes up theframe is also used as the railfor moving parts to ride on.One or more bearings makecontact with the surface ofthe extrusion, allowing parts
like the print bed to slideacross it. These designs areusually very economical butmay not be capable of thesame quality as designs thathave dedicated smoothrods.
Whetherit’sarodorarail,thereareafewcharacteristicsthatareimportantforthemtoworkwell:
Thesmoothnessofthe
surfaceThehardnessofthesurface
Thestraightnessofthepart
Thestiffnessofthepart
Thediameterofthepart
Thesmoothnessofthesurfaceisimportantforreducingfriction,ofcourse.Buttheotherqualitiesneedalittlemoreexplanation.
Theimportanceofsurface
hardness,forexample,maynotbeimmediatelyobvious.Afterall,it’snotlikeyou’llbehammeringitoranything.Butwhatyouwillbedoingiscontinuouslyrunningabearingbackandforthalongthelengthofthepart.Overtime,thebearingcangougethesurface,makingthesurfacesignificantlylesssmooth.Andasyouknow,withoutasmoothsurface,frictioncanbeaproblem.
Howstraighttherodorrailisalsoimportantforareasonthatshouldbereadilyapparent—ifit’snotstraight,movementwon’tbeperfectlylinear.Butwhatmaynotbeapparentisexactlyhowstraightitneedstobe.Inmanufacturing,straightnesshasitsownspecificgeometrictolerance(aspecificationforhowcloselytherealpartmustmatchthedesign).Thistoleranceisvery
tightinrodsandrailsmanufacturedforuseinlinearmotionsystemsbutmaynotbequitesostrictforrodsandrailsthatarespecificallymadeforthispurpose.Forthatreason,it’simportanttobecarefulaboutchoosingthosecomponentswhenbuildinga3Dprinter.
Luckily,thereasonrodsorrailsneedtobestiffisstraightforward.Rodsorrails
usedinlinearmotionsystemssimplycan’thaveanyflexinthemundertheintendedloads.Thisandtheothercharacteristicsmeanthatonlyafewmaterialsarebothsuitablefortheapplicationandaffordable.
Ofthosematerials,themostcommonlyusedseemstobehardenedstainlesssteel.Whenmanufacturedproperly,thismaterialcanpossessall
ofthedesiredcharacteristicswhilealsobeingcorrosionresistantandfairlyinexpensive.Othermaterialscanbeused(andmayevenbenecessaryinsomeindustries),butfor3Dprinters,theredoesn’tseemtobeanyreasontouseanythingelse.
Thelastfactor,particularlyforsmoothrods,isthediameteroftherod.Whiletherodsdon’tgenerallyprovide
structuralsupportfortheframe,theydoneedtosupporttheweightofthemovingparts.Howmuchweighttheyneedtosupportandhowlongtheyarewilldeterminethediameterneededfortherods.Thisvariesfromone3Dprintertoanother,butsmoothrodsareusuallysomewherebetween8mmand12mm(althoughtheycanbebiggerorsmallerinsomecases).
BearingsAsfarasmechanicalcomponentsgo,bearingsaresomeofthemostfundamentalpartsinuse;infact,they’realmostcomparabletofastenerslikenutsandbolts.Anytimetherearemovingparts,bearingspracticallybecomeanecessity.Thepurposeofabearingissimplytoreducefrictionbetweenmoving
parts.Therearetwobasictypesofbearings:solidbearings(usuallycalledbushings)androllerbearings.Asolidbearingdoesn’thaveanyrollingelementsandisusuallymeanttobelubricated.Thebearingitselfismadeofeithermetalorplastic.Whenit’smadeofmetal,themetalshouldbeofadifferenttypethantheshaftit’sincontactwith.
Generally,asoftermetalisidealsothebearingwearsinsteadoftheshaft.Combinedwithalubricant,asolidmetalbearingcanbesatisfactoryforreducingfriction.
HOT TIPWhen looking at
bearings, be aware thatmany different names areused to describe essentiallythe same things. Forexample, solid bearings areoften called sleeve bearings.This is a result of their longhistory, their use in manydifferent industries, and veryminute differences betweensimilar bearings.
Solidplasticbearingsaremadefromself-lubricatingtypesofplasticlikenylon,Delrin(thetradenameforastrong,self-lubricatingplastic),orsomevariationofpolyethylene(likeUHMW,HDPE,orLDPE).Thesetypesofplasticshaveverylowcoefficientsoffriction,allowingthemtobeusedforsolidbearingswithoutanylubricant.Thismakesthemidealinmechanicalsystems
wherelubricantisimpractical,likeinsealedsystemsorwhenlubricantcandamagethemechanisms.
Theprimaryadvantageofsolidbearingshastraditionallybeencost.Becausetherearenosmallmovingparts,they’reinexpensivetomake,whichreducestheoverallcostofthemachinebeingbuilt.Theywerealsothefirsttypeof
bearingused,beforetheIndustrialRevolutionmaderollerbearingsfeasible.Evennow,solidbearingsarestillthemostcommontypeofbearinginuse.
Butwhenamechanismneedstohaveaslittlefrictionaspossible,rollerbearingsaretheanswer.Thesetypesofbearings,oftencalledballbearings,usuallyhavethreecomponents:aninnersleeve,
anoutersleeve,andanumberofsmallballsbetweenthetwo.Asonesleeveisrotated,itrollsontheballs.Forlinearballbearings,theshaftitselfactsastheinnersleeveandtheballsrollbetweentheshaftandoutersleeve.
Bothsolidbearingsandrollerbearingscomeintwobasicstyles:linearandrotational.Theapplicationdetermineswhichkindisneeded.Ifthe
movingpartsonlyneedtorotateonasingleaxis,rotationalbearingsareused.Iflinearmotionisneeded,likeina3Dprinter,linearbearingsareused.Therefore,nomatterthetypeofbearing,yourprinterwillneedthemtobelinear.
Stepper
MotorsWithallofthismotionhappening,therehastobesomekindofelectricmotorinvolvedtoactuallymakethingsmove.Therearemanytypesofelectricmotorsthataretechnicallycapableofprovidingthismotion.However,thereisonetypeinparticularthatisperfectlysuitedtothetask:astepper
motor.
Thekeycharacteristicofasteppermotorisitsabilitytorotateveryprecisely.Aplainoldelectricmotorwillsimplyrotatewhenelectricityisapplied,andwillrotatefasterastheamountofelectricitybeingappliedisincreased.Thissimplicitymeansthataregularelectricmotorisveryefficient,butitalsomeansthey’redifficulttoprecisely
control.Thisiswhatsteppermotorswerecreatedspecificallytoaddress.
Asteppermotorisatypeofelectricmotorconstructedspecificallytoallowprecisecontrol.Thatprecisionisimportantforproducingaccurateanddetailedprints.Itdoesthisbyrotatinginaseriesofsteps,insteadofjustrotatingcontinuouslywhenelectricityisconnected.A
commonsteppermotor,likewhatisusedinmost3Dprinters,canhave200stepsforeverycompleterotationoftheoutputshaft.
Theinternalconstructionofasteppermotor.Noticehowtheteethoftherotoraredesignedsothatwhentheyarealignedtoonephase,theyaremisalignedtothe
other.
HOT TIPWhile stepper motors
are by far the most commontype of motor for 3D printing,there are other options.Continuous-rotation servoscan be used and are alsofairly accurate. And, in amethod similar to whatpaper printers use, a plainelectric motor can be used incombination with an encoderstrip to monitor position. Butthe ease of use and highprecision of stepper motors
continues to make themideal for 3D printing.
Becausethesteppermotorcanmoveasinglestepatatime,thatmeansitcanrotatetheoutputshaftprecisely1.8°foreachstep(fora200-stepmotor).Additionally,atechniquecalledmicrosteppingcanbeusedtoreduceeachstepevenfurther.Microsteppingishandledby
thesteppermotorcontroller,andmanycontrollersarecapableof1/16microstepping.Thatmeanseachindividualstepcanbebrokenupinto16microsteps.At16microstepsona200-stepmotor,theoutputshaftiscapableofbeingpositionedat3,200individualplacesperrotation.That’sonepositionevery.1125°,anincrediblelevelofprecisionthatsimply
isn’tpossiblewithanyotherkindofelectricmotor.
Thishighlevelofprecisioniswhatmakessteppermotorsidealformachineslike3Dprinters.Evenwithoutusingmicrostepping,theaccuracyisveryhigh.Ifafullrotationofthesteppermotoroutputshaftmovesanaxis1mm,eachstepwillmoveit.005mm.Thatmeanseachaxisofthe3Dprintercanbe
positionedanywherewithinatoleranceof+/-.0025mm,andthatcanbemadesignificantlymoreaccuratewithmicrostepping.
Withthatkindofaccuracy,it’seasytoseewhysteppermotorsaresopopular,andwhythey’reusedinvirtuallyall3Dprinters.Buthowdoestherotationalmovementofasteppermotortranslateintothelinearmotionneededfor
3Dprinting?That’swherebelts,pulleys,andleadscrewsorthreadedrodscomein.
Belts andPulleysBeltandpulleysystemsareoneoftheoldestmechanicalsystemsinhistoryandhavea
widerangeofuses.Asidefromsimplytransmittingmotionfromonepulleytoanother,theycanbeusedtoreduceadrivesystemtogainmechanicaladvantage.
DEFINITIONMechanical
advantage is theamplification of force withthe use of a tool ormechanical system. This isusually achieved by trading
movement distance forforce. A lever is the mostbasic example of this,because if one side of thefulcrum (pivot point) is twiceas long as the other, it willdouble the force exerted(though it will also doublethe distance it needs to bepushed). This same basicconcept is applied in a vastarray of machines usingthings like gears, pulleys,screws, and so on.
Initsmostbasicsetup,abeltandpulleysystemisverysimple.Onepulleyisdrivenbyamotorofsomekind,andabeltconnectsittoasecondpulleytotransmittherotationofthefirstpulleytothesecond.Ifbothpulleysarethesamesize,thedrivesystemhasa1:1ratioandthepurposeofthesystemissimplytotransferpower.
Mechanicaladvantageis
achievedwhenthepulleysareofdifferentsizes.Ifthefirstpulley(thedrivepulley)issmallerthanthesecond,theresultingoutputhasmoretorquebutlessspeed.Whenthesystemisreversedandthefirstpulleylargerthanthesecond,theoutputhasgreaterspeedbutreducedtorque.
Multiplepulleyscanbeusedtogainevengreaterreductionsandsignificant
mechanicaladvantage.Systemslikethatarewhatallowapersontoliftloadsmanytimestheirownweight.Inthesameway,suchasystemcanallowarelativelylow-torque(buthigh-speed)motor,likeanelectricmotor,tohandlehighloads.
However,whilesomeprintersusemechanicaladvantageintheirdesigns(especiallyforthecoldend),otherskeep
powertransmissionata1:1ratio.Tomovetheprintbed,forexample,apulleyisattachedtotheoutputshaftofasteppermotorandasecondpulleyismountedontheoppositeendoftheaxis.Abeltisloopedaroundthemandattachedtotheprintbedinthemiddle.Astheoutputshaftofthesteppermotorspins,itpullsthebeltandthereforemovestheprintbedalongtheaxis.
Asfaraspulleysystemsgo,thisisaverysimplesetup.However,mechanicaladvantagecanbeintroducedbychangingthesizeofthedrivepulley.Thebiggerthedrivepulleyis,thefurtheritwillmovetheprintbedperrevolution.Ifthespeedatwhichthesteppermotorturnedremainedconstant,thesizeofthedrivepulleywoulddeterminethespeedandtorqueoftheprintbed
movement.Alargedrivepulleywouldmoveitquicklybutwithreducedprecisionandtorque.Asmalldrivepulleywouldmoveitslowlybutwithhigherprecisionandmoretorque.Thisallowstheprintermanufacturertoprioritizespeedorprecisionintheirdesigns.
Whilethesetupisprettymuchstandard,thephysicaldesignofthebeltsand
pulleyson3Dprinterscanvary.Theycanbeaslowtechasafishinglineactingasabelt,wrappedaroundadrumactingaspulley.Ortheycanbehigh-techpartsdesignedspecificallyforthispurpose.Mostcommonly,though,3Dprintermanufacturersusesimpletoothedbeltsandpulleys.
Thesetoothedbeltsandpulleysarefairlysimilartoa
carengine’stimingbelt.It’sarubberbeltwithteethononesidethatmeshwithpulleysthatalsohaveteeth.Thissetupisidealbecauseitdoesn’tslip,thebeltdoesn’tstretch,andit’saffordable.
Beltandpulleysystemsaregreatforhorizontalmovement(theXandYaxes),wherethebeltdoesn’thavetobearanyweight.Allithastodoispulloneway,
andthenbacktheotherway.
ThisisacommonGT2beltandpulleysetup.
Weight-
BearingComponentsforConverting MotionWhenrotationalmotion(fortheverticalZaxis)needstobeconvertedintolinearmotion,andthereisasignificantloadonthe
system,leadscrewsorthreadedrods(whichareinexpensivealternativestoleadscrews)arethebestoption.Therearetworeasonsleadscrewsareidealforsuchasituation:theycanprovideasignificantmechanicaladvantagewithoutcomplicatedpulleyorgearsystems,andtheleadscrewitselfcanbeartheweightofthecomponentsit’slifting.
Aleadscrewdrivesystemisalotlikeaboltandnut;infact,that’sprettymuchwhatitis(physicallyspeaking).Whenyourotatetheboltbutdon’tallowthenuttospinwithit,itpushesorpullsthenutalongtherotationalaxis.Aleadscrewworksinthesameway:thesteppermotorturnstheleadscrew,whichpushesorpullsthenutupanddownontheZaxis.Thenutisattachedtowhatever
componentsneedtobemovedintheZaxis,allowingthesteppermotortoliftorlowerthemasitturns.
Lead ScrewsLeadscrewscomeinallkindsofsizestosuittherequirementsofthemachinebeingbuilt.Theycomeinvariousdiametersandpitches(metricandstandard)with
onestartthreads,twostartthreads,orevenmore.Thediameterisfactorinthestrengthandstiffnessoftheleadscrewandcanhelpthesmoothrodsconstrainmovementtoasingleaxis.Thethreadpitchdeterminesthemechanicaladvantageofthedrive,becauseitiswhatcontrolshowfarthenutismovedperrotationoftheleadscrew.
AleadscrewandnutlinearmotionsystemfortheZaxis.
DEFINITIONThe pitch of a
thread is the distance from
one thread to the next. Thisis what determines how farthe screw and nut will move(relative to each) with onefull rotation. For example, anM8 screw has a standardpitch of 1.25mm. So if youhave a lead screw with anM8 thread, every full rotationof the lead screw will movethe nut 1.25mm.
Despitehowcommonandutilitarianleadscrewsare,
theyarestillverypreciselymadeparts.Thecomplexityofthespecificationsofleadscrews(theyneedtobesmooth,straight,hard,andstiff),alongwiththeprecisionrequiredwhenmachiningthem,makesthemveryexpensive.Many3Dprinterdesignsrequiretwoofthem(oneoneithersideoftheprinter),whichjustaddstothebill.Infact,thiscostissohighthatleadscrewscanend
upbeingthemostexpensivepartsonaconsumer3Dprinter.Withsuchahighpriceforsuchabasicpart,3DprintermanufacturersandDIYbuildershavetriedtofindanothersolution.
Threaded RodsInanefforttoreducethecostof3Dprinters,many
designershavechosentosubstitutethreadedrodsforleadscrews.Athreadedrodisessentiallyaverylongheadlessbolt.Thegeneralpurposeofathreadedrodisforfastening,whichisdonebythreadinganutontoeitherend.
Becausethreadedrodsareonlyintendedtobefasteners,themanufacturersputlittleimportanceonthequalities
thatareconsiderednecessaryforleadscrews.Theresultisapartthatisn’tparticularlystraightorhardanddoesn’thaveperfectlymachinedthreads.Athreadedrodisjustgoodenoughtothreadanutontowhilebeingsortofstraight.
Manufacturersareabletomakethreadedrodsatverylowscostswhilestillmaintainingtherequired
precision.Thatcostissolowthatthreadedrodsaregenerallyabout1/10thepriceofleadscrews.Atthatkindofprice,it’seasytoseetheiralluretoa3Dprintermanufacturertryingtobuildanaffordableconsumerprinter.
Athreadedrodusedinplaceofaleadscrew.
Butthereisaprettyglaringproblemhere:ifthreadedrodswork,whywouldanyonespendtheextra
moneyonleadscrews?Fromthepointofviewofthosewhousethreadedroads,thereareacoupleofdifferentanswerstothatquestion.
Onepossibilityisthatleadscrewsarenecessaryforcertainkindsofmachinesbutnotfor3Dprinters.Theargumentisthattheloadsbeingputontheleadscrewbya3Dprinteraresmall,andtheprecisionrequiredisfairly
low.Ifarealleadscrewmakesadifferenceatall,it’sverysubtle.
Anotherpossibilityisthatthereisaperceptibledifferencebetweenleadscrewsandthreadedrodsbutthatitcanbedesignedaround.Theideahereisthatleadscrewsareonlynecessaryifthey’refirmlyconstrained,inwhichcasethey’reactingkindoflikea
smoothrodtorestrictmovementperpendiculartotheZaxis.Butbecausetherearealreadysmoothrodsforthispurpose,itisunnecessaryfortheleadscrewtoprovidethatfunction.Becausethethreadedroddoesn’thavetorestrictperpendicularmovement,it’snotnecessaryforitbeperfectlystraight.Allthatmattersisthatitdoesn’tinadvertentlyintroduceperpendicular
movement.
Atthispoint,thereisverylittleevidencefororagainsttheeffectivenessofthreadedrodsthatisn’tjustanecdotal.Thequalityofa3D-printedpartistheresultofthecomplexinteractionofmanydifferentpiecesofhardwareandmanysettingsinsoftware.It’sdifficulttocontroleveryotherfactorwhileonlychangingfrom
leadscrewstothreadsinordertoscientificallytestthis.However,theanecdotalevidenceseemstosuggestthatthreadedrodscanworkwellifthedesignisdoneproperly.
Attachmentand
ConnectionComponentsWhetherleadscrewsorthreadedrodsarebeingused,therealwaysneedstobeawaytoconnectthesteppermotorstothem.And,oncethatsteppermotorisspinning,thereneedstobeawaytotranslatetheturningscrewintomovementonthe
Zaxis.Bothoftheseproblemshavespecificpartsdesignedtosolvethem:acouplerconnectsthesteppershafttothescrew,whileanutattachespartstothatscrewsotheycanbemovedalongtheZaxis.
CouplersThejobofthecouplerisratherunspectacular:it’sjust
theretoconnectoneshafttoanother.However,variouskindsofcouplersexisttoserveallsortsofspecificpurposes.Therearecouplersdesignedtoflexandothersthataredesignedspecificallytominimizeflex.Somecouplersaresupposedtobespringytoabsorbshockintheshaft,whileothersaredesignedtoavoidthis.
Inthecaseof3Dprinters,
whichtypeofcouplerisidealdependsonwhetherleadscrewsorthreadedrodsarebeingused.Ifaleadscrewisbeingused,it’sreasonabletoassumeitisbothverystraightandverystiff.Ifthat’sthecase,thecouplershouldbesolidandstiffaswell,sothatmovementissmoothandconstrainedtothatrotationalaxis.
FASCINATING FACTIn many RepRap 3D
printer designs, the coupleris simply a small piece offlexible plastic tubing that fitsover the stepper motor shaftand the threaded rod. Thetubing is then zip tied onboth ends to keep it tight.This low-tech solution isboth very inexpensive andsurprisingly effective.
However,ifathreadedrodisbeingused,it’sverylikelyit’snotstraightatall.It’sprobablyslightlybentandmaybealittlebitflexibleitself.Insuchacase,it’spreferableforthecouplertobeflexibleinordertoabsorbthemovementcausedbythethreadedrodnotbeingstraight.
Astandardcouplermeanttoallowsomeflexibility.
Thecoupleritselfcanbemadefromavarietyofmaterialsandinavarietyofstyles.Aluminum,steel,and
brassareallpopularmaterials,andtypesofplasticcanbeusedaswell.Designscanbeasimplestraighttube,canbecutinahelixtoabsorbforcesalongtherotationalaxis,orcanbecutwithslotstoabsorbforcesperpendiculartotherotationalaxis.Mostwillhavesomesortofsetscreworclampingapparatustolockthecouplerontobothshafts,buteventhatmaychangeinsomespecific
circumstances.
NutsAnutisasimplepartthatisthreadedontoathreadedrodorleadscrew.Itcanbeabasichexnutlikethekindyoucursewheneveryouhavetodoworkonyourcar,oritcanbeaspecializedtypeofnutmeantspecificallyforlinearmotionsystems.
Likemostothercomponents,materialscanvary.However,it’swidelyconsideredtobenecessaryforthenutmaterialtobesofterthanthematerialoftheleadscreworthreadedrod.Thereasonisbasicallythesameaswhybearingsandbushingsaremadeofsoftermetals:sothattheywearfirst.Asexpensiveasleadscrewsare,itwouldbearealshameifthethreadsgotworndownbya50-centnut.It’smuch
bettertoreplacetheinexpensivenutasitgetsworndown.
Withthatsaid,nutsthatareusedon3Dprintersaren’toftenassimpleasthekindyoubuyinbulkatthehardwarestore.Becausethesenutsaremeantforpowertransmission,notfastening,theyhavetwouniquequalities:
Theyneedtohavesomekindofmountonthem.
Theyshouldresistbacklash.
Theneedforamountisprettystraightforward;therehastobewaytoattachthepartsyouwanttomove.Forthisreason,therearenutsmadewithmountingflangessothemovingpartscanbeconnected.Thesemountingflangescomeinvarioussizes,shapes,andholepatterns,but
thosedetailsaren’treallyrelevanttotheiroperation.
Whatisrelevanttotheoperationofascrewdrivesystemisbacklash.Backlash,inthiscontext,iswhenthenutslightlyshiftswhentherotationofthescrewreverses.Thedirectionofmovementsuddenlychangesandthenutmovesslightlybecauseofthespacebetweenthethreads.Tobeclear,thisisaverysmall
shift,comparabletothemovementyoufeelifyoutrytowiggleanutthat’sthreadedontoabolt.ButI’mtalkingaboutamachinethatistryingtomovewithveryhighaccuracy,soevenaslightshiftcanaffectthat.
Thesolutiontothisproblemisthecreativelynamedanti-backlashnut.Averybasicdesignforthisconsistsoffourparts:ahousing,two
normalnuts,andaspring.Thehousingfitsoverthenutsandkeepsthemfrommovingindependentlyofeachother,whilethespringsitscompressedbetweenthetwonuts.Becausethespringiscompressed,it’sconstantlypushingoutonbothnuts.Thisensuresthatthetopsurfaceofonenut’sthreadsisincontactwiththescrew,whilethebottomsurfaceoftheothernut’sthreadsisin
contact.Thiseffectivelyeliminatesbacklash,becausewhenthedirectionischanged,oneofthenut’sthreadswillalwaysalreadybeincontactwiththescrew.
Asimpleanti-backlashnutdesign.
Withallofthisdetailonthenutsandscrewsof3Dprinters,itmayseemlikethey’reverycomplexmachines.Andinaway,theyare.Buttherealityisthatmostmachinesareatleastthiscomplicatedwhenyoureallygetintothedetails,and3Dprintersaren’tanexception.
The Least You
Need to KnowSmoothrods,rails,andbearingsareusedtoprovidesmooth,low-frictionmovement.
Steppermotorsareuniquetypesofelectricmotorsthatareperfectlysuitedfor3Dprintingbecauseoftheirprecision.
BeltsandpulleysareoftenusedtodrivetheXandYaxesof3Dprinters,while
leadscrewsareusedtodrivetheZaxis.
Threadedrodscanbeusedinplaceofleadscrews,butthereissomeambiguityabouthowwelltheydothejob.
Couplersareusedtoattachleadscrewsorthreadedrodstosteppermotorshafts,whilenuts(anti-backlashorotherwise)areusedtoattachthemovingpartstotheleadscrews.
CHAPTER
7
TheExtruder
In This Chapter
HowFFFextrusionworks
Differenttypesofcoldendsandhotends
Changingnozzles
Whentouseaprintfan
Thebenefitsofmultipleextruders
ExtrusionisthekeytoFFF(andFDM)3Dprinting.It’swhatseparatestheFFFprintingprocessthatissocommoninconsumerprintersfromtheotherprocessesthat
areusedinmoreexpensive3Dprinters.Extrusionitselfisusedinmanywaysinmanufacturing,butthetechniquehasbeenfine-tunedfor3DprintinginFFFprinters.Inthischapter,Icoverhowextrusionworksandhowitaffectsyourprints.
What Is
Extrusion?Ingeneralterms,extrusionisanyprocessusedtoejectmaterialwithaspecifiedcross-section.Extrusioninmanufacturingcanbeusedtocreateawiderangeofparts,withthemajorrestrictionbeingthatthecross-sectionoftheparthastoremainconstant.
WithFDM/FFF3Dprinting
(seeChapter2),extrusionistheprocessusedtoactuallydepositnewplasticontotheprintbed.Italsoreferstohowthealuminumframepiecesthatareoftenusedtobuild3Dprintersarecreated.
Complexshapesarepossiblewithextrusioninmanufacturing,buttheprocessismuchsimpleron3Dprinters.Plasticisextrudedoutofaplain
circularnozzle,resultinginaverysimplecylindricalextrusion.
Toextrudeplastic,FFFprintersuseasystemknownasanextruderthatfeedsfilamentintoahotendtobemelted,andthendepositsitontheprintbed.Howexactlythisisdonevariesalittlebitdependingontheparticular3Dprinter,butthey’reactuallyallprettysimilar.
The Cold EndThesystembeginswithfeedingthefilament,ataskhandledbyamechanismcalledacoldend.Thecoldendpullsfilamentandpushesitintothehotend.Asmorefilamentispushedintothehotend,themeltedfilamentissqueezedoutthroughthenozzlefordepositionontotheprintbed.Sothepurposeof
thecoldendiseasytounderstand;it’sjusttheretofeedthefilament.Butit’smorethanjustthat;itneedstobeabletofeedthefilamentpreciselyandconsistently.
HOT TIPThe terminology used
for various parts of 3Dprinters can often be a bitconfusing. Sometimes,different terms are used todescribe the same part
based on themanufacturer, plus thehobbyist nature of 3Dprinting has led to partsbeing developedsimultaneously byindependent designers.
The cold end is one exampleof this confusion. The coldend is what feeds filamentinto the hot end, which inturn melts the filament.However, the cold end isoften referred to as theextruder instead. This is
made even more confusing,because extruder is the termused to describe the entiresystem (cold end and hotend). To try and avoid anyconfusion in this book, I’llrefer to the individualmechanisms as the cold endand the hot end, and thesystem as a whole as theextruder. But be aware thatthese terms may be useddifferently depending on thesource.
It’simportantthattheprinterbeabletoextrudeexactlytherightamountoffilamentinorderfortheprintqualitytobegood.AsImentionedinChapter3,thelayerthicknessisdeterminedinpartbyhowmuchfilamentisbeingextruded.Theslicingsoftwareknowsexactlyhowmuchfilamentisbeingpushedoutofthehotendatanygiventimeandcalculatestheextrusionasneeded.
Inorderfortheslicertobeabletomakeusablecalculations,thecoldendhastobecapableofconsistentlyfeedingexactlythepredictedamountoffilamentatalltimes.Ifthefilamentisfedinconsistently,thecalculationsbeingmadebytheslicersoftwarebecomeuseless,resultingineitheroverextrusionorunderextrusion(bothofwhichwillyieldapoor-
qualityprint).
Forthisreason,theextruderhastobeproperlycalibrated.Extrudercalibrationisabsolutelynecessarytomakesurethecorrectamountoffilamentisbeingextruded.Thisisasimplematterofmakingsuretheamountoffilamentbeingfedintothehotendmatchesthepredicatedamountandadjustingthefeedrateifit’s
notright.
Todothis,coldendsusesteppermotorsforprecisecontrol—thesametypeofsteppermotorsthatareusedformovingtheaxesofthe3Dprinter.Thesteppermotorturnssomesortofhobbledboltordrivegearthathasserrationstogripthefilament,andabearingonaspringprovidestension.Thefilamentisheldtightbetween
thebearingandhobbledbolt,andasthesteppermotorturns,itpushesthefilamentintothehotend.
Thesetupforthismechanismdependsonwhatkindofcoldendisbeingdesigned,andtherearetwodistincttypes:directfeedandBowden.
Direct FeedThemostcommontypeof
coldendisthedirectfeedstyle(nottobeconfusedwithdirectdrive,whichIdiscusslaterinthischapter).It’scalledadirectfeedcoldendbecausethehotendislocatedrightbelowit,andfilamentisfeddirectlyfromthedrivegearintothehotend.
Therearetwoadvantagestothisdirectfeedstyle:it’sasimplesetup,anditreducesthechancesofthefilament
bindingorbunchingbeforeitentersthehotend.
Thesimplicityofthesetupisprobablytheprimaryreasonwhydirectfeedcoldendsaresopopularandwhyalmostallconsumer3Dprintersusethem.Themotoranddrivegeararemountedrightabovethehotend,andthefilamentispulledfromaspool,whichcanbemountedanywhereonoraroundtheprinter.
AdirectfeedcoldendmadebyPrintrbot.
Butasconsumer3Dprintertechnologyhasmaturedandourunderstandingofithasimproved,ithasbecome
apparentthattherealbenefitofadirectfeedcoldendisthatitlessensthelikelihoodofthefilamentbunching.Asflexiblefilament(amaterialwhichfeelssimilartorubberorsilicone)and1.75mmfilamenthavegainedpopularity,it’sbecomemoreofaproblemforfilamenttobunchupandjambeforeitactuallyentersthehotend.Havingthedrivewheelrightabovethehotendtopushthe
filamentdoesn’tleaveanyspaceforittobunchup.
BowdenBowden-stylecoldendsarenamedafteramechanismcalledaBowdencable.ABowdencableisapush/pulldevicethatconsistsofahollowtubewithasolidorstrandedcablerunningthroughitthatletsyou
transmitpushingorpullingforceoveradistancewithaflexiblecable.Thismechanismisusedinallsortsofthings,includingairplanecontrols,bicyclebrakesandgearshifters,motorcycleclutches,throttlecables,andmanyotherthings.
FASCINATING FACTThere is some debate
over who Bowden cables
are named for. The originalBowden mechanism wasinvented and patented byErnest Monnington Bowden,but Sir Frank Bowden(founder of the RaleighBicycle Company) is oftengiven credit for its invention.The two men were notrelated, but their commonlast name is surely a factorin the confusion. ErnestBowden actually licensed hispatent to Sir Frank Bowdenfor use in his bicycle brakesystems, which just further
confuses things.
ABowdencoldendworksonasimilarprinciple.Insteadofhavingthedrivemechanismrightabovethehotendontheextrudercarriage,it’slocatedelsewhereonthe3Dprinter.Ahollowandflexibletube(usuallymadefromalow-frictionplasticlikepolytetrafluoroethylene
[PTFE])runsfromthecoldendtothehotend,andthefilamentispushedthroughit.Thissetupservesoneveryspecificpurpose:toremovemassfromtheextrudercarriage.
ABowdencoldendonanUltimaker2.
(CourtesyofUltimaker)
Havingasmallerandlighterextrudercarriageisadvantageousfortwo
reasons:
Itreducestheoverallsizeofthe3Dprinter.
Itimprovesprintquality.
Itreducesthesizeoftheprinterbecausetheextrudercarriagedoesn’tneedasmuchroomtoreachtheendsoftheprintbed.Howitaffectsprintqualityisalittlemorecomplicated.
Movingalargeamountofmassaroundquicklyisadifficulttask.Everytimethedirectionofthemovingmasschanges,theprinterhastoovercometheinertiaofthatmass.Butunlessyou’reprintingatslowspeeds,the3Dprinternevercompletelyovercomestheinertiaanditslightlyovershootstheintendedstoppingpoint.Whenitovershoots,itresultsinunevenedgesaround
features,makingfinedetailsimpossibletoprintwell.
Alarge,movingmassalsocreatesvibrationsastheextrudercarriagemovesbackandforth.Thisresultsinaneffectcalledghosting,wherefaintoutlinesofafeatureshowuponthesurfacesnearthosefeatures.Sothemassoftheextrudercarriageendsuphavingaprettysignificanteffectontheoutputqualityof
a3Dprinter.
Bowdenstylecoldendssolvethisproblembyremovingasmuchmassaspossiblefromtheextrudercarriage.Ittakestheweightofthesteppermotoranddrivegearandmovesittoastationarylocation.But,ofcourse,thissetupdoeshaveitsdrawbacks.
Intheprevioussection,Iexplainedhowdirectfeed
coldendsreducethechancesoffilamentbunchingbeforeitentersthehotend.Andthat’sexactlytheproblemwithBowdencoldends.Withsuchalongdistancebetweenthedrivegearandthehotend,thereisalotofroomforthefilamenttobunchandjam.Thismakesitdifficulttouse1.75mmfilamentandalmostimpossibletouseflexible1.75mmfilament.
Direct Drive vs.GearedWhetheraBowdenordirectfeedcoldendisbeingused,thereisstilltheoptionofpushingthefilamenteitherwithadrivegearconnecteddirectlytothesteppermotorshaftorwithahobbledboltconnectedtoagearsystem.AsI’msureyou’resickofhearingbynowinthisbook,
eachhasitsadvantagesanddisadvantages.
Directdriveextrudersuseadrivegearthatismountedontothesteppermotorshaft.Thisistheabsolutesimplestwaytodesignanextruder,whichisalwaysagoodthing.However,ittakesalotofforcetopushfilamentthroughahotend.Becausetheyarelightandcompact,directdriveextrudershave
difficultyhandlingtheforceneededfor3mmfilament.
Ontheotherhand,gearedextrudersuseapairofgearstogainmechanicaladvantageandthetorqueneededtoforce3mmfilamentthroughthehotendwithoutdifficulty.Thedisadvantage,ofcourse,isthatthegearsaddsizeandweighttotheextrudercarriage,althoughthat’snotaproblemforBowden
extruderssincethecoldenddoesn’tmove.
AGreg’sWadeReloadedgeareddirectfeedcoldend.
The Hot EndAsyou’velearnedinprevious
chaptersofthisbook,thehotendservesoneveryspecificpurpose:tomelttheplasticfilament.Itmustmeltthefilamentveryquicklyinorderforthe3Dprintertoprintatareasonablespeed.Forthattohappen,thetemperatureofthehotendhastobeveryhigh.
Exactlyhowhighthetemperatureneedstobedependsonthematerialbeing
printed,thefilamentmanufacturer,andevensometimesthespecificbatchoffilament.Forthemostcommonmaterials,however,thehotendneedstobeoperatingattemperaturesbetween180°Cand250°C.Toputthatintoperspective,that’sapproximatelythesametemperatureasthehotoilinadeepfryer.
AnUbishotend,whichisusedonPrintrbot3Dprinters.
Somematerials,however,requiremuchhottertemperatures.Forexample,polycarbonateisanextremely
toughplasticthatrequirestemperaturesof300°Cormoretoprintwell.Withsuchhightemperatures,it’seasytoseethatsomespecialhardwareisrequired.Inordertoheatupthehotend,twospecificelectroniccomponentsareneeded:athermistorandaheatingelement.
Thermistor
Athermistorisatypeofvariableresistorsimilartoathermocouplethatchangesbasedonhowhotitis.Thetermthermocoupleisoftenusedincorrectlytodescribethethermistorusedin3Dprinters,butthey’reactuallyentirelydifferentcomponents.Theyworksimilarly,butthermistorsaregenerallymoreaccurateandarebettersuitedfor3Dprinters.
Thethermistorismountedontothehotendatthepointwherethefilamentissupposedtobemelted.Asthehotendheatsup,theresistanceofthethermistorchanges.Thecontrolboardofthe3Dprintermonitorsthisresistancechangeandusesittocalculatethetemperatureofthehotend.Inessence,it’sbasicallyjustaveryaccuratethermometerthatcanbereadbythe3Dprinter.
DEFINITIONA thermocouple is
a type of temperature-measuring device used in awide range of industries. It’sinexpensive and doesn’trequire a power source,which makes it ideal forsome applications. However,thermocouples aren’t veryaccurate, which generallymakes them unsuitable foruse in 3D printer hot ends.
Thermistorsareaccuratetowithinafractionofadegreewhenproperlysetup.Becausethermistorsaremadebyavarietyofmanufacturers,sometimesforslightlydifferentapplications,thepropersetupcanvary.Tosolvethisproblem,3Dprinterfirmwarecomeswithinformationformanydifferentthermistormodelsinordertomakethetemperaturereadingasaccurateas
possible.Withanaccuratetemperaturereading,the3Dprintercanpreciselycontrolhowhotthehotendis.Thisallowstheusertosetthetemperatureasnecessaryforaspecifictypeoffilament.
Butgettinganyaccuratetemperaturereadingisonlyhalfoftheequation;the3Dprinteralsoneedstobeableheatupthehotendtothedesiredtemperatureusinga
heatingelement.
Heating ElementTheheatingelementforahotendisamuchmoregeneraltypeofcomponentthanthethermistor.Virtuallyallelectronicheatingelementsworkinthesameway,whetherit’sforanelectricspaceheater,anelectricstove,orthehotendofa3D
printer.Allofthesedevicesuseamethodcalledresistiveheating.Resistiveheatingisanextremelybasicprocess,andisreallyjustafundamentalpropertyofelectronicsingeneral.Whencurrentpassesthroughaconductor,itheatstheconductor.Ifthevoltageinacircuitremainsconstant,theheatofaresistorincreasesastheresistancedecreases.
Thecurrentdrawalsoincreasesalongwiththeheat.Sowhentheobjectiveistoheatsomethingup,likeahotend,aheatingelementwithalowresistanceisused.
Thatlowresistancedrawsahighcurrent,andthereforealotofpowerneedstobedissipatedbythesourceoftheresistance(inthiscase,theheatingelement).Thatpowerisdissipatedinthe
formofheatinguptheheatingelement,andinturnthehotend.
Physical Designand MakeupThecombinationofthethermistorandtheheatingelementallowsthe3Dprintertosetthetemperatureofthehotendveryaccurately.Whenthe3Dprinterisfirst
turnedonandthehotendisstillcool,constantvoltageisappliedtotheheatingelementtoheatitupasfastaspossible.Asitgetsclosetothedesiredtemperature,thatvoltageispulsedtoslowdowntheheatingprocessuntilitreachesthecorrecttemperature.
Onceit’satthecorrecttemperature,theprintermonitorsthethermistorand
turnstheheatingelementonandoffasnecessarytomaintainthetemperature.Itdoesthiswithamethodcalledpulse-widthmodulation(PWM),whichflipsthevoltageonandoffveryquicklytoaverageoutintoaspecificvoltagetokeepthetemperatureconstant.
Sohowisitdesignedtomakethisprocesshappen?Thedesignofahotendisa
reflectionofafewgoals:
Maintainaconstanttemperaturenearthenozzletomeltthefilament.Thisisachievedwithaheatingblockwherethethermistorandheatingelementarelocated.Theblockisheatedandmonitored,andhasaholerunningthroughwherethenozzleismounted.Asthefilamententerstheheatingblock,it’srapidlymeltedinto
moltenplastictobesqueezedthroughthenozzle.
Heatuptheheatingblockquickly.Theheatingblockisgenerallymadefromametalwithahighthermalconductivity.Thisallowstheheatfromtheheatingelementtoberapidlytransferredtotheheatingblock;therefore,itheatsupquickly.
Getcooloveraveryshortareasoitcanbemountedto
the3Dprinter.Themountisoftenmadeofthesametypeofplasticthatisbeingextruded,sothehotendneedstobecoolatthatpointinordertonotmeltthemountitself.Tomakethatpossible,aheatsinkisoftenlocatedbetweentheheatingblockandthemount.Insomedesigns,thereisafanlocatedontheheatsinktocoolitevenmore.Thiscanlowerthetemperaturefromavery
hot300°Ctoroughlyroomtemperatureoverjustacoupleofinches.
HOT TIPHot ends are often
interchangeable, dependingon the type of mount theyuse. Progress is rapidlybeing made in improving hotend designs, and newmodels are frequently beingreleased. So it’s probablynot necessary to choose a
3D printer based on the hotend as long as it uses acommon or replaceablemount.
Traditionalhotenddesignsincorporateavarietyofmaterials,includingsomehigh-temperatureplastics.Forcommonfilamentmaterialslikepolylacticacid(PLA)andacrylonitrilebutadienestyrene(ABS),thisis
perfectlyacceptablebecausetheplasticcanhandlethetemperaturesrequiredforthosematerials.Butforsomematerialsthathavehighermeltingpoints(likepolycarbonate),thehotendhastobeheatedtotemperaturesthattheplasticinthehotendcan’twithstand.
Forthatreason,all-metalhotendsarebecomingpopular.A
hotendmadecompletelyfrommetal,insteadofusingsomeplasticparts,canbeheatedtomuchhighertemperatureswithoutriskingdamagetothehotenditself.Withanall-metalhotend,manymorematerialtypescanbeprintedsuccessfully,allowingtheuserawiderrangeofpossibilities.
ThisE3DV5isanall-metalhotendandrequiresactivecooling
fromafan.
Butmakingahotendcompletelyoutofmetal
presentssomedesignchallengesthatarestillbeingovercome.Oneofthebiggestproblemsisthattheheatfromtheheatingblockistransferredmoreefficientlyacrosstheentirehotend,meaningthemountingpointcangettoohotforthemount.Tosolvethisproblem,muchlargerheatsinksareneeded,andafanisoftenrequired.Buttheversatilityofall-metalhotendscandefinitelymake
thechallengesworththetrouble.
The NozzleThenozzleisoftenconsideredtobepartofthehotend,butit’sareplaceablepartthatIthinkdeservesitsownsection.Hotendsalmostalwayscomewithacompatiblenozzle,buthot
endmanufacturersalsogenerallyselladditionalnozzlesinavarietyofsizes.
Whywouldyouwanttopurchasedifferent-sizenozzles?Because,asI’veexplainedinChapter3,thesizeofthenozzleisoneofthefactorsthatdetermineslayerheight—thelargerthenozzle,themoreofanincreaseinlayerheight.Nozzlesizeisn’ttheonly
thingthatdetermineslayerheight,sothereissomewiggleroomforeachnozzlesize.Butifyouwanttoprintalayerheightthatissignificantlydifferent,itcanbeworthchangingnozzles.
Nozzlesthatcomewithhotendsareusuallysomewherebetween.25mmand.50mm,becausethat’sageneralsizethatisusefulformostprinting.Butnozzlescanbe
muchsmallerforspecializedprintingwhereveryfinedetailisrequired.Alternatively,someprintscanbedonewithlargernozzlesinordertoprintlargeobjectsmorequickly.
WATCH OUT!Nozzles aren’t
generally compatiblebetween different hot endmodels. This is because hot
ends usually have nozzlesthat are made specifically forthem. They use differentthreads, are different sizes,and are sometimes evendifferent shapes. For thisreason, it may be a goodidea to check ahead of timewhat nozzles are available ifyou know you’re going toneed a smaller- or larger-than-usual nozzle.
Print FansInadditiontothehotendfansthatareusedtocoolthehotendformounting,oneormorefanscanalsobeusedtocooltheprintedobjectitself.Thefanisdirectedtowardtheextrudedfilamentasitexitsthenozzleinordertoquicklycooltheplastic.
Thepurposeofcoolingtheplasticistogetfromthehigh
temperatureneededforextrusiontoroomtemperatureasquicklyaspossible.Plasticexpandswhenitgetshotandcontractsasitcools.Thatcontractioncanresultinwarpedparts,becausetheentirepartcoolsandcontractstogether.Soafancanbeusedtocoolthefilamentquicklytoavoidtheentirepartcontractingatonce,whichhelpstoreducewarping.
Somefilamentmaterials,likePLA,alsorequireactivecoolingfromafantocombatdeformation.PLAisverysoftuntilitcools,andtheplasticcansagasitsbeingprintedifit’snotcool.Thisisespeciallyapparentwhenprintingoverhangsorbridges,whichwillsagdramaticallyiftheplasticistoohot.
Havingafanblowingontheplasticcomingoutofthe
nozzleallowsyoutoprintoverhangsandbridgeswithoutthembecomingdeformed.Justafanblowinginthedirectionofthenozzlecandoalottohelp,butinordertocooleffectively,fanshroudscanbeused.Theshroudactsasasortoffunneltodirectairtoaverysmallareajustbelowthenozzlewherethefilamentisbeingdeposited.Thisveryquicklycoolsthefilamentassoonas
itexitsthenozzle,sotheplasticgetshardanddoesn’tdeform.
Whetheryoushoulduseafanisdeterminedbythematerialyou’reusing.ForPLA,aprintfanisvirtuallyanecessity.Forothermaterials,likeABS,afancanactuallybedetrimentaltoprintquality.ABSisn’tassoftasPLAwhenit’sextruded,soafanisn’tneededtokeepit
fromdeforming.Infact,activelycoolingABSwithafancanmakeitsolidifytoomuchandcankeepitfromstickingtothepreviouslayer.
Ifthe3Dprinterisequippedwithaprintfan,it’susuallycontrolledviasoftware.Theslicersoftwarecanturnthefanonandoff(orevenonatdifferentspeeds)throughouttheprintingprocess.It’scommontohavethefanonat
differentpartsoftheprint(likeforoverhangs)andoffforothers(likethefirstfewlayers).Inlaterchapters,I’llbegoingoverwhenandhowtouseprintfans,butfornow,youshouldjustbeawareofitspurpose.
UsingMultiple
ExtrudersAllFFF3Dprintershaveatleastoneextruder,butit’salsopossibletohavemultipleextrudersonthesameprinter.Thesearemountedrightnexttoeachothersotheprintercanusealloftheextrudersatthesametime.Themostbasicreasonfordoingthisissoyoucanprintasinglepartinmorethanonecolor.But
thepossibilitiesintroducedbyusingdualextruders(ormore)canbemuchmoreexcitingthanjustmakingcolorfulparts.
TheKraken,alsomadebyE3D,hasfourextrudersbuiltintoa
singleunit.(CourtesyofE3D)
For SupportMaterialOneveryusefulwaytotakeadvantageofadualextrudersetupistouseoneextruderforregularfilamentandtheotherforsupportmaterial.Therearespecialkindsoffilamentwhichareformulatedspecificallyforthistask.Somemanufacturers,suchas
Stratasys,havedevelopedtheirownformulasforaccomplishingthistask,butinmanycasespatentskeepthesefrombeingavailableonprintersfromothermanufacturers.Whenitcomestothemostcommonsupportmaterialinconsumerprinting,peopletendtousehigh-impactpolystyrene(HIPS).HIPSisatypeofplasticthatdissolvesinacommonsolventcalled
limonene.Limonenedoesn’taffectPLAorABS,soHIPScanbeusedforsupportmaterialandthendissolvedaway,leavingtheprintedpartuntouched.
Usingasolublesupportmateriallikethisinthesecondextrudereliminatesthehassleofhavingtomanuallyremovesupportmaterialmadefromthesamematerialasthepart.Notonly
isitalotofworktoremovesupportmaterial,itcanbedifficulttodowithoutdamagingthepartiftherearefinedetails.Insomecases,supportmaterialcouldbealmostimpossibletoremoveif,forinstance,it’ssupportinginternalgeometrythatcan’tbereached.
Dualextruderswithastandardmaterialandsolublesupportmaterialcompletely
solvethisproblem.Youcanjustprintthepartwiththetwotypesoffilament,andwhentheprintisfinished,youcansoakitinalimonenesolution.Afterafewhours,thesupportmaterialisdissolvedawayandyourfinishedpartcanberemoved.
For Filaments withDifferent
PropertiesAnotherusefordualextrudersisprintingtwokindsoffilamentwithdifferentpropertiesatthesametime.AsinglepartcouldbeprintedwithahardABSplasticandalsoaflexiblefilament,forexample.Youcouldprintaplastictoolwithasoftrubberyhandle.Orapartcouldbemadewithflexible
jointstoallowmovement.
Withthewiderangeoffilamentsonthemarkettoday,therearealotofpossibilitiesforanimaginativeperson.Youcantakeadvantageofthedifferentmeltingpoints,coefficientsoffriction,hardness,andflexibilityofvariousfilamenttypestocreateuniqueobjects.Thisisanareaof3Dprintingthatis
juststartingtobeexplored,andalotofunconventionaldesignsarepossible.
HOT TIPIt doesn’t stop with just
dual extruders either. Youcan already purchase a four-extruder assembly meant forconsumer printers that letsyou print four differentfilament typessimultaneously. You coulduse this to print two different
colors of ABS, a flexiblefilament, and HIPS supportmaterial all at the same time.Or you could use it for anyother combination offilament materials that youthink would be useful.Imagine the kinds of designsyou could come up with!
The Least YouNeed to Know
AnFFFextruderconsistsofacoldendthatfeedsfilamentintothehotend.
Directfeedcoldendsfeedmorereliably,whilethelowermassofBowdencoldendscanimproveprintquality.
Inordertoheatupthehotend,twospecificelectroniccomponentsareneeded:athermistorandaheatingelement.
Multipleextruderscanadda
greatdealofversatilitytothekindsofprintsa3Dprinteriscapableof.
CHAPTER
8
The BuildPlatform
In This Chapter
Materialscommonlyusedfor
buildplatformsThepurposeofheatedbedsandbuildchambers
Differentsurfacetreatmentstoimproveadhesion
Whenitcomesto3Dprinters,everypartonthemachineisimportanttoitsfunctionality.That’strueevenforthingsthatseemsimpleanduncomplicated,likethebuildplatform(alsocalledaprintbedorbuildplate).Thebuild
platformisactuallyjustascrucialasanyoftheotherpartsandcanbejustascomplicated.
Thebuildplatformiswheretheprinteractuallydepositstheplastictomakethepart.Thisseemsstraightforward,butinorderfortheprinttobesuccessful,theplasticneedstostickwelltotheplatform.Thereareafewfactorswhichdeterminehowwellthe
plasticwillstick:theflatnessoftheplatform,howlevelitis,whatmaterialthebuildplatformismadeof,andanysurfacetreatmentswhichareappliedtotheplatform.
Inthischapter,Igothroughallyouneedtoknowaboutthebuildplatform,includingwhatit’smadeof,thevariouspartsthatmakeitup,andthesurfacetreatmentsusedonittoimproveadhesion.
BuildPlatformMaterialsThereareahandfulofmaterialsthatarecommonlyusedforbuildplatforms,suchasglass,borosilicate,aluminum,andcopper.Whatallofthesematerialshaveincommonistheycanbemade
veryflat.Theflatnessofthebuildplatformisessentialforensuringtheplasticstickstothebed.Thisisbecausethenozzlehastoremainataveryspecificheightabovethebuildplatformfortheextrudedfilamenttoadheretothebed,andthatheightwouldn’tremainconstantiftheplatformweren’tflat.
DEFINITION
Borosilicate, also known asPyrex (one of its tradenames), is a type of glassthat is formulated to reducethermal expansion. Becauseit’s much less prone tothermal expansion thannormal glass, it’s at a muchlower risk of thermal shock.Thermal shock can cracktraditional glass if it’s quicklyheated or cooled unevenly,a problem that borosilicatedoesn’t experience.
Inadditiontobeingflat,thebuildplatformhastobeconstructedfromamaterialthatthemoltenfilamentcanactuallystickto.Somematerialsaretooslick,andtheextrudedfilamentsimplywon’tsticktoit.Anidealmaterialwouldletthefilamentstickverywellwhileit’sprinting,andthenallowittocomeoffeasilywhentheprintisdone.Ifitstickstoowellaftertheprintisdone,it
canbedifficulttoremovethepartwithoutdamagingit.
Forthisreason,specialtybuildplatformsarebeingdevelopedjustfor3Dprinters.Thisisabrandnewtypeofproduct,buttheselectionshouldincreasedramaticallyinthecomingyears.Theplatformsthemselvesaremadefromavarietyofmaterials,dependingontheparticular
manufacturer.Butthegoalisthesameforallofthem:fortheplastictostickwellwhileprintingandcomeoffeasilywhentheprintisdone.Butinmanycases,inorderforthattowork,thebuildplatformneedstobehot.Thisiswhereheatedbedscomein.
Heated Beds
Heatedbeds,asthenameimplies,keepmaterialwarm.Aheatedbedworksprettysimilarlytoahotendinprinciple:athermistormeasurestemperature,whileresistiveheatingisusedtogetthebedhot.Inthiscase,though,theentirebedisabigresistorthatheatsupinsteadofjustasmallheatingelement.
Conventionalheatedbedsare
largeprintedcircuitboards(PCBs)specificallydesignedwithlargecoppertracesthatactasaverylow-ohmresistor(duetoOhm’slaw).Whenvoltageisapplied,thisdrawsaverylargeamountofcurrent.
Alarge12×12-inchPCBusedforheatingthebuildplatform.
FASCINATING FACTRecently, other types of
heated beds have started togain popularity in theconsumer 3D printingindustry. This includessilicone heating pads, whichhave long been popular inother industries. Unliketraditional PCB heat beds,these are flexible and aremanufactured in a widerange of sizes and shapes.
Withallofthatpowerflowingthroughwhatisbasicallyaresistor,theheatedbedgetshot—anywherefrom60°Cto120°Ciscommon.This,inturn,heatsupthebuildplatform.Andjustlikewiththehotend,the3Dprintermonitorsthetemperatureusingthethermistor(seeChapter7)andadjuststhevoltagegoingtotheheatedbedtokeepthetemperaturesteady.
Oneofthebenefitsofaheatedbedisreductioninthewarpingofapart.AsIcoveredinearlierchapters,warpinghappenswhenthepartcontractsastheplasticcools.Aheatedbedcanhelpcombatthisproblembykeepingthepartwarmasitisbeingprinted.Forsomematerials,likeABS,aheatedbedisbasicallyarequirement.Othermaterials,suchasPLA,don’tneeda
heatedbedbutcanstillbenefitfromone.
Thisisthereasonwhysome3Dprintersincludeaheatedbedandothersdon’t.Generally,onlyinexpensive3Dprinterscomewithoutaheatedbed.ThoseprinterscanusuallyonlysuccessfullyprintPLA.InordertoprintABS(andmanyothermaterials),aheatedbedisanecessity.
Inadditiontoreducingwarping,heatedbedsalsohelpfilamentsticktothebuildplatform.Heatingthebuildplatformgivesthefilamentanice,hotsurfacetostickonto,whichistrueforallofthematerialtypesonthemarket.Whileit’snotabsolutelynecessaryforallmaterials,aheatedbeddoesalotforgettingthefirstlayeroftheprinttoadherewelltothebuildplatform.
Heated BuildChambersandEnclosuresAheatedbuildchamberisusedtopreventwarping.Itcontainstheheatgeneratedbythehotendandheatbed,keepingtheairwarmand
reducingdrafts.Unlikeanenclosure,aheatedbuildchamberincludesactiveheating.Thismeansaheatingelementandsomekindoftemperaturesensor(athermistor,forexample)areplacedinsideoftheenclosuretoheatitup,almostlikeanelectricoven.ThiscangettheairinsideveryhotandcanalmostcompletelyeliminatewarpingwithmaterialslikeABS.
Unfortunately,notall3Dprintersincludeheatedbuildchambers.ThemainreasonisthatStratasysownsthepatentforheatedbuildchambers,meaningtheyusethemextensivelyontheirprofessionalFFF3Dprintersbutothermanufacturerscan’taddthemtotheirprinters.Ifitweren’tforthatpatent,you’dsurelyseeheatedbuildchambersonalotofconsumer3Dprinters.
HOT TIPStratasys now owns
MakerBot, a popularconsumer 3D printermanufacturer. BecauseStratasys has the patent forheated build chambers, it’slikely that in the future thetechnology could be used onconsumer 3D printers madeby MakerBot. If a heatedbuild chamber is importantto you, it might be worthwaiting for this to happen.
Butthatpatentdoesn’tkeepmanufacturersfromaddinganunheatedenclosuretotheirprinters.Manyconsumer3Dprintershaveenclosuresthatcanholdintheheatgeneratedbythehotendandheatbed,keepingtheairwarmandreducingdrafts.Warmairaroundtheprinterkeepsthepartwarm,soevenwithoutactiveheating,thiscandoalottoreducethewarpingthatiscommonwhenprinting
withABS.
SurfaceTreatmentsAnotherwaytoreducewarpingistomakesurethefirstlayeroftheprintsticksverywelltothebuildplatform.Mostofthematerialsthatbuildplatforms
arecommonlymadefromdon’tworkverywellontheirown.Evenwithaheatedbed,thefilamentdoesn’talwaysadherewell.Sotomakesurethatplasticreallysticks,avarietyofsurfacetreatmentscanbeappliedtothebuildplatform.Thesetreatmentsareusuallysomesortoftape,film,orglue.
The3Dprintingcommunityhascomeupwithalotof
novelwaystoensurethefilamentadhereswelltothebuildplatform.Ahandfulofthesemethodsstandoutasbeingespeciallyeffective,andhavecometobeasortofstandardoperatingprocedureforhobbyistsdoing3Dprinting.Therearetoomanytocoverallofthem,butI’llgooversomeofthemorepopularoneshere.
Painter’s TapeOneofthemostpopularsurfacetreatmentsispainter’stape.Thisisjusttheplainoldbluetapeyouputaroundyourtrimwhenyoupaintyourwalls.Thetapeisappliedwiththeadhesiveonthebuildplatform,sotheentirebuildplatformiscompletelycovered.Youthenprintdirectlyontothenonadhesivesideofthepainter’stape.
Printingapartonabuildplatformcoveredwithpainter’stape.
Thetextureofthetapegivesthefilamentgoodpurchasesoitstickswell.Someparticular
brandsseemtoworkbetterthanothers,butmostofthecommonlyavailabletypesfoundathardwarestoresworkprettywell.
Painter’stapeseemstoworkbestforPLAonunheatedbeds.ItcanbeusedwithABSandonheatedbeds,butthereareusuallybetteroptions.It’salsonotaparticularlydurablesurfacetreatment,soyou’llprobablyneedtoreplacethe
tapeoften(maybeevenaftereveryprint).
White GluePolyvinylacetate(PVA)-basedwhiteglue(commonlyreferredtobythetradenameElmer’sGlue)isalsoapopularwaytogetgoodadherencetothebuildplatform.Thisisthesameglueyouprobablyused
throughoutyourchildhoodforvariouscraftprojects,andit’seasytofindatjustaboutanyofficesupplystore.
Toapplyittothebed,mixasmallamountwithwaterataratioofabout1:1.Next,useasmallbrushorpapertoweltospreaditaroundonthebuildplatform;itcanbeappliedontopofbluepainter’stapeordirectlytothebuildplatform.Ideally,youwantathinlayer
leftbehindasthewaterevaporates,leavingastickyresidue.Thewaterdoesn’thavetobecompletelyevaporatedforyoutostartprinting,butthebuildplatformshouldn’tbewet.
Thisgluehelpsthefilamentstickforobviousreasons—it’sglue,afterall!Whenusedinconjunctionwithbluepainter’stape,itcanalmostcompletelyeliminatewarping
whenprintingPLA.However,ABSwarpssomuchthatyoumightnotbeabletocompletelyovercomeit.Also,beawarethatyou’llalmostcertainlyneedtoreplacethetape(ifusing)andreapplythegluebeforeeveryprint.
Polyimide FilmPolyimidefilmisusedina
handfulofparticularindustriesandapplications,includingforsuperconductorsandspacecraft.It’sverystrong(eveninthinsheets)andflexibleandcanprovideelectricalinsulationandthermalinsulation.PolyimidesheetsandtapeareusuallyreferredtobythetradenameKapton(developedbyDuPont).
Polyimidefilm,likeblue
painter’stape,hasasurfacetexturetowhichfilamentadheresverywell.Additionally,itcanwithstandveryhightemperatures,andthereisvirtuallynoriskofdamagingitwiththeheatgeneratedby3Dprinters.ABSalsosticksverywelltopolyimidefilm,whichmakesitespeciallyusefulwhencombinedwithaheatedbed.
A12×12-inchsheetofpolyimidefilm.
Oneofthemostdesirablepropertiesofpolyimidefilm,however,isitsstrength.Itcanbereusedmanytimeswithout
damage,whichisconvenientofcourse.Theonlyrealdownsidestopolyimidefilmareitsavailabilityandcost.It’snotusuallyavailableinlocalstoresandhastobeorderedonline.And,evenwhenorderedonline,itcanbefairlyexpensive.
PET FilmPolyethyleneterephthalate
(PET)filmisusedsimilarlytopolyimidefilm,althoughitsphysicalpropertiesandtraditionalapplicationsarequitedifferent.PETfilmcomesinsheetsandtapelikepolyimidefilmandcanbeappliedinthesameway.
Infact,inthecontextof3Dprinting,PETfilmisreallyverysimilartopolyimidefilm.However,itdoesn’thavethesameabilityto
withstandhightemperaturesthatpolyimidefilmhas.Polyimidefilmisoftenusedtoholdthermistorsontothehotend,forexample,andthisisanapplicationPETfilmisn’twellsuitedto.Itjustcan’tholduptotheheatfromthehotend.Butitworksjustfineforthebuildplatform.
ABS Juice
ProbablythemosteffectivewaytoeliminateABSwarpingistouseasortofgluemadefromABSandacetone,commonlycalledABSjuiceorABSglueinthe3Dprintingcommunity.BecauseABSdissolvesinacetone,ABSjuiceismadebydissolvingalargeamountofABSfilament(neworfromfailedprints)inpureacetone,whichcaneasilybefoundatyourlocalhardware
store.
DEFINITIONAcetone is a
common household andindustrial solvent. Acetonebreaks down styrene, whichallows it to dissolve ABS.
Whenkeptinasealedcontainertokeeptheacetonefromevaporating,this
producesaviscousfluid.Itcanthenbeappliedtothebuildplatform,eitherdirectlyontoglassorontopolyimidefilmorPET.Thismixtureisextremelysticky,andwhenathinlayerisapplied,theacetonequicklyevaporatesaway.Aftertheacetoneisevaporated,afilmofABSisleftfirmlystucktothebuildplatform.
Onceyoustartprinting,the
moltenABSfilamentisdepositedontopofthisABSfilmthatisstucktothebuildplatform.ABSadhereswelltoitself,andsoitsticksextremelywelltothefilm(whichremainsstucktothebuildplatform).Theresultisaprintthatremainsveryfirmlyattachedtothebuildplatform.
UsingABSjuicecanalmostcompletelystopABSparts
fromwarping,makingitveryuseful.However,itcanalsobeprettymessytoworkwith.Ithastobemadeaheadoftime,keptinasealedacetone-safecontainer,andhastobeappliedtothebuildplatform.Anditworkssowellthatitcanbedifficulttoremovepartswithoutdamagingthem.
Furthermore,thecoloroftheABSjuicewillcoatthe
bottomoftheprintedpart.So,forexample,ifyouprintedawhitepartwithblackABSjuice,thebottomwouldendupatleastpartiallyblack.However,thiscanbecounteractedbyusinganatural(uncolored)ABSfilamentwhenmakingthejuice.
Hairspray
Onesurprisingsurfacetreatmentthathasrecentlygainedpopularityishairspray.ThesamestuffthatgaveFarrahFawcett’shairitsfamousflipcanhelpyourpartssticktothebuildplatform.And,maybeevenmoresurprisingly,itactuallyworksverywell!
Asoddasitmaysound,hairspraymayjustbeperfectfor3Dprinting.It’scheap,it
canbefoundinanygrocerystoreordrugstore,it’seasytoapply,itworkswell,anditdoesn’tdamageoraddcolortoyourparts.Whatmorecouldyouwant?
Thekindsofhairspraythatworkbestaretheonesthataremarkedwithwordslikeextraorsuper,orideallyextrasuperhold—thestrongerthehairspray,thebetter.Allyouhavetodois
sprayafewcoatsontothebuildplatform,waitforittodry,andthenstartprinting!However,itmayhelptoremovethebuildplatformfromthe3Dprinter,ifpossible,inordertoavoidgettinghairsprayonanyofthemovingpartsormechanisms.
Hairsprayisessentiallyjustanaerosoladhesive,soyou’rereallyjustsprayingalayerof
glueontoyourbuildplatform.Thisworksverywelltokeepprintedpartsstuckwelltotheplatform,andwhenusedonaheatedbed,itcancompletelyeliminatewarping.EvenlargeABSpartscanbesuccessfullyprinted,whichisprettygoodforabeautyproduct.
Hairspraybeingappliedtheprintbedtohelpthepartstick.
The Least YouNeed to Know
Buildplatformscanbemadefromavarietyofmaterials,aslongasthey’reveryflat.
Heatedbedsaren’tnecessaryforallmaterialsbutarerequiredforsome.However,theycanimproveprintqualityforvirtuallyallmaterials.
Heatedbuildchamberscandoalottoreducewarping,butthetechnologyispatented.Becauseofthis,mostconsumer3Dprintersdonothaveheatedbuild
chambers;however,manystilluseenclosures.
Therearemanysurfacetreatmentsthatcanbeappliedinordertoimprovetheadhesionofthefilamenttotheprintbed,suchaspainter’stape,whiteglue,polyimidefilm,PETfilm,ABSjuice,andhairspray.
CHAPTER
9
ControlComponentsIn This Chapter
Whatendstopsareandhow
theyworkWhatthecontrolboarddoes
HowLCDcontrollersandSDcardscanhelp
Controllinga3Dprinterisnoeasytask,becausethereisalotofhardwaretosimultaneouslycoordinate.Themovementofthreeaxeshastobecoordinated,thefilamentbeingfedbythecoldendhastobecontrolled,the
temperaturesofthehotendandheatedbedneedtobemonitoredandadjusted,andfanshavetobeturnedonandoff.Thisallrequiresprocessingpower,significantamountsofcurrentbeingpassedthroughthecontrolboard,andthesimultaneouscontrolofmultipleoutputsandinputs.
Inthischapter,Iexplainwhathardwareiscommonlyused
tocontrolconsumer3Dprinters,someoptionalcomponentsyoucanusetohelpwiththecontrols,andhowtheyallwork.
Inadditiontotherequiredcomponentsthathavetobecontrolled,therearealsoacoupleofthingsthatcanbeoptionallyusedaswell.AnLCDscreenandSDcardreader,forexample,canbeusedsoit’snotnecessaryto
haveacomputerconnectedtothe3Dprinterforittorun.ThereisalsooneothertypeofcomponentIhaven’tyetdiscussed,butwhichisveryimportant:anendstop.
End StopsAnendstopisasmallandsimplecomponentwithoneveryspecificpurpose:totell
the3Dprinterwhenithasreachedtheendofeachaxis.Thisisaveryimportantfunction,becauseit’stheonlywaytheprintercanknowwherethezeropointofeachaxisis.Withoutendstops,youwouldhavetomanuallypositionthehotendeachandeverytimeyouusedtheprinter,whichwouldbeespeciallydifficultfortheZaxis(whichhastobeatanextremelypreciseheight
abovethebed).
FASCINATING FACTEnd stops are also
used on CNC mills forexactly the same reason. ACNC mill, just like a 3Dprinter, needs to knowwhere the zero point is foreach of its axes in order tooperate properly. The onlymajor difference is that CNCmills don’t have a constantzero point for the Z axis;
instead, they need to findthe top of the material beingmilled. For this reason, the Zheight is either set manuallyor with a probe.
Withsuchanimportantjobtodo,youmightthinkthatendstopswouldbeexpensivecomponents.Butinreality,they’reactuallygenerallyverycheapparts.That’sbecausethey’resimply
switches—justverysensitiveswitches.Thekeytraitsofanendstopswitcharesensitivityandrepeatability.Theyneedtobetriggeredbythefaintesttouchandatexactlythesamedistanceeverytime.Thisisusuallydoneinoneoftwoways:mechanicallyoroptically.
Mechanical End
StopsMechanicalendstopsarethesimplest,cheapest,andprobablymostreliabletypeofendstop.Theyare,quiteliterally,justaphysicalswitchthatistriggeredwheneachaxisgetstoitszeropoint.Theswitchconsistsofasmallarmthatsticksoutfromthebodyoftheswitch.Whentheextrudercarriage,buildplatform,orZassembly
reachestheendofitsaxis,itpushesonthearmtotemporarilytriggertheswitch.
Theswitchiseitheropenorclosedinitsnormalstate,andthecontrolboard(whichI’lldiscusslaterinthischapter)monitorswhatstateit’sin.Whencontactismadeonthearm,thestateoftheswitchisreversed.Soifitwasopenbefore,it’sswitchedto
closed.Ifitwasclosedbefore,it’sswitchedtoopen.Whenthecontrolboardseesthestatechange,itknowsthatparticularaxisisatitszeropoint.
Aswitchwiredtobenormallyopenhasasmallamountofvoltageappliedtoonecontactoftheswitch.Whentheswitchistriggered,theconnectionisclosedandthecircuithasvoltage
flowingthroughit.Thecontrolboardseesthecircuithasvoltageflowingandknowsthattheswitchhasbeenflipped.
Switchesthatarewiredtobenormallyclosedworkintheoppositeway.Whentheswitchisn’ttriggered,thevoltageisalwaysflowingthroughthecircuit.Butwhentheswitchistriggered,itcutsofftheflow.And,as
expected,thecontrolboardseesthatchangeandproceedsaccordingly.
Thisisacommonmechanicalendstopswitch,wiredtobenormally
closed.
It’sgenerallyconsideredtobebettertowiretheendstopswitchtobenormallyclosed.
Thisisbecausea3Dprintercanbedamagediftheswitchisn’ttriggeredandtheaxiskeepstryingtomovepastitsendpoint.Withtheswitchnormallyclosed,anydamagetothecircuitwillresultintheswitchbeingtriggered,soitactsasasortoffailsafe.
However,interferencefromthesteppermotorwirescaninducecurrentintheendstopwires.Soit’spossibleforthe
switchtobephysicallytriggeredbutforthevoltagetostillreachthecontrolboard.Ifthishappens,thataxiscouldcontinuemovingwhenit’snotsupposedtoandcouldcausedamage.
HOT TIPInterference can be a
major problem for end stopswitches, either causingfalse triggers or failure to
trigger. The interference isgenerally caused be steppermotor wires, which are oftenrun right next to the end stopwires. To protect against thisinterference, the end stopwires should ideally be ashielded and twisted pair. Ashielded and twisted pair isa type of wiring where pairsof wires are twisted togetherand then electricallyshielded to preventinterference.
Whentheendstopiswiredtobenormallyopen,anyinducedcurrentcausedbyinterferencewouldsimplycauseafalsetrigger,andnodamagewouldoccur.Sobothsetupshavetheirprosandcons,andoneisn’tnecessarilyobjectivelybetterthantheother.
Optical End Stops
Opticalendstopsservethesamefunctionasmechanicalendstops.Butinsteadofbeingtriggeredbyphysicalcontact,theyaretriggeredbychangesinlight.Thisishandledbyacomponentcalledaphotointerrupter.Nophysicalcontactisnecessary;instead,anopticalendstopistriggeredwhenthelightinthephotointerrupterisinterrupted.
Aphotointerrupterworksverymuchlikethesensorsusedonautomaticgaragedooropeners.Itconsistsofanemitterandareceiver(aphototransistor)thatfaceeachother.Infraredlightisoutputbytheemitter,andthereceiversensesthatinfraredlight.Whenitseesthelight,theswitchisn’ttriggered;however,whenthatbeamoflightisbrokenandthereceivernolongersensesthe
infraredlight,theswitchbecomestriggered.
Thisworksalmostexactlylikeyourgaragedoorsensors.Whensomethingisblockingyourgaragedoor,theinfraredlightbeamisbrokenandyourgaragedooropenerknowsnottoclose.Thephotointerruptersusedinopticalendstopsdothesamething,justonamuchsmallerscale.
Inaphotointerrupterusedfor
opticalendstops,theemitterandreceiveraremountedrightnexttoeachother.They’regenerallyonlyafewmillimetersapart,leavingjustenoughroomforsomethingtotriggertheswitch.Thisproximitymakesthemverysensitive,unlikeyourgaragedoorsensors.Thissensitivityiswhatmakesthemdesirableforusein3Dprinters.
AsI’vepreviouslydiscussed,
it’simportantforthe3Dprintertoknowexactlywheretheendpointofeachaxisis(especiallytheZaxis).Mechanicalendstopsdothisjobwell,butbecausethey’remechanical,thereisalwaysgoingtobesmallamountofdifference(evenifit’sonlyafractionofamillimeter).Opticalendstopshavenomovingpartsandaretriggeredassoonastheinfraredlightbeamisbroken.
Thismakesthemveryprecise,sothe3Dprinterknowsexactlywheretheendpointiseverytime.
Ofcourse,opticalendstopsdohavesomedrawbacks.Themostobviousoftheseisthecostoftheendstopitself.Mechanicalendstopsarejustprecisemechanicalswitches,makingthemverycheap.Ontheotherhand,opticalendstopsuseelectrical
components(namelythephotointerrupter),whicharemoreexpensive.Thecostdifferenceisn’thuge,butitisnotable(thoughopticalendstoppriceshavedroppedsignificantlyinrecentyears).
Opticalendstopsarealsoslightlymorecomplicatedtowire,astheyrequirethreewires(whilemechanicalendstopsonlyrequiretwo).Thisisbecausetheyneedconstant
powerinadditiontoasignalwire.Mountinganopticalendstopisalsoquiteabitmorecomplicatedthanamechanicalendstop,becausesomesortoftabhastobeusedtointerrupttheinfraredlightbeam.Thismeanstheendstophastobeperfectlylinedupwiththetabonthataxisinordertofunction,whileamechanicalendstopcanreallybemountedinanywaythatletsitgetpushedby
somethingonthataxis.
Other Kinds of EndStopsBecauseendstopsarereallyjustswitchesthatgettriggeredwhentheaxisreachesitsendpoint,therearealotofmechanismsthatcanbeusedasendstops.Anythingthatcanactasaproximityswitchcould
probablywork,technicallyspeaking.Thismeansthereareothertypesofendstopsoutthere,evenifthey’renotparticularlypopular.
Oneofthese,forexample,isaHalleffectsensor.AHalleffectsensorsensesanearbymagnetandvariesitsoutputvoltagebasedonthehowcloseorpowerfulthemagnetis.Soasmallmagnetcanbemountedonthemovingpart
ofa3Dprinteraxis,andwhenitgetsclosetotheHalleffectsensor,theendstopistriggered.
DEFINITIONThe Hall effect,
discovered by Edwin Hall in1879, is the tendency forvoltage in a circuit to changewhen exposed tomagnetism. It can beharnessed to createproximity sensors and issometimes used for endstops and probes.
BeyondHalleffectsensors,
peoplehaveexperimentedwithawiderangeofdifferenttypesofdevicestomakeendstops(everythingfromultrasonicdistancesensorstoaccelerometers).Butsofar,mechanicalandopticalendstopsremainthemostcommontypesofendstopsbyalongshot.Theirrelativelylowcostandreliabilitymakethemidealforusein3Dprinters,andtherejusthasn’tbeen
anythingthatworksanybetter.
ControlBoardsInordertomonitorandcontrolthoseendstopsandalloftheothercomponentsofa3Dprinter,acontrolboard
isneeded.Thecontrolboardisasmallcomputerthat’sessentiallythebrainofthe3Dprinter.Itisresponsibleforbothinterpretingcommandsfromtheslicingsoftwareandsignalsfromthe3Dprinter’ssensorsandusingthatinformationtocontroltheoperationoftheprinter.
Controlboardscomeinavarietyofdifferenttypesandstylesfrommanydifferent
manufacturers.Thereareopen-sourceboardsmeanttoworkwithvarioustypesof3Dprinters,open-sourceboardsmeanttoworkwithspecific3Dprinters,andproprietaryboardsthatonlyworkwiththeparticularprintertheyweredesignedfor.Buttheyalltendtoworkinroughlythesameway,withsimilarinputsandoutputs.
Arduinos andProprietary ControlBoardsEverycontrolboardneedstobeabletodobasicallythesamethings:
Takethecommandsoutputtedbytheslicingsoftwareandusethemasinstructionsforoperatingthe3Dprinter
Monitorandheatupthehotend(andprobablyaheatedbed,too)
Simultaneouslycontrolfourormoresteppermotors—oneforeachaxis,andafourthfortheextruder
Monitoratleastthreeendstops
Doingallofthisrequiresprocessingpower,ofcourse.Butmoreimportantly,itrequiresalotofinputsand
outputs.Everycomponentonthe3Dprinterneedstohaveitsowninputoroutput(dependingonitsfunction),andtheyallhavetobecontrolledormonitoredatthesametime.Forthisreason,Arduinosareapopularchoiceasthebaseofmostopen-sourcecontrolboards.
Arduinos,bytheirverynature,areverywellsuitedtothistask.They’re
programmable,haveonboardprocessingcapabilities,andhavenativesupportformanyinputsandoutputs.Whenusedfor3Dprinting,Arduinosaregenerallyequippedwithashieldthatprovidesalloftheconnectionsforthesteppers,hotend,endstops,andsoon.Or,insomecases,theArduinoandconnectionsareallintegratedintoasinglecircuitboardforsimplicity
andeaseofuse.
DEFINITIONIn the context of
Arduinos, a shield is acircuit board designed to beattached to the Arduinoboard. Shields are generallyused to expand thecapabilities of Arduinos byadding either moreconnections or sensors.They are usually designedfor a specific application (like
GPS tracking or to interfacewith another device),although plenty of general-use shields exist.
ARAMPS1.4controlboard,whichisashieldforanArduinoMega.
Proprietarycontrolboardsthatareclosedsourceandaren’tArduinobasedstillworkinthesamewaybutare
justdevelopedbythemanufacturerspecificallyforuseina3Dprinter.Theystillhavetohaveallofthesamecapabilitiesforprocessingandinputandoutput;theonlydifferenceistheyaren’tbuiltonanArduino.It’sanalogoustointernetbrowsers:whetheryou’reusinganopen-sourcebrowserlikeFirefoxoraclosed-sourcebrowserlikeInternetExplorer,theydisplaywebpages,andyou
canusethemtosurftheinternet.
Changing orUpgrading ControlBoardsInmanycases,thecontrolboardscanbeinterchangeable.Forexample,ifyoudecidedyouwantedtoadddualextruders
toyourprinterbutthecontrolboarddidn’thavethepropersupport,youcouldpotentiallyremovetheoriginalcontrolboardandreplaceitwithonethatsupportsdualextruders.Thisispossiblebecausetheothercomponentsofthe3Dprinteralltendtobethesame,regardlessofwhomakesit,andtheyworkinthesameway.
However,complicationscan
beencounteredwhenitcomestofirmwareandsoftware.Firmwareismadespecificallyforthecontrolboard;itcan’tbetransferredbetweendifferentkindsofcontrolboards.Andinsomecases,onlyspecificslicingandcontrolsoftwarecanbeusedwithaparticularcontrolboard.Thisisn’tthecasewithopen-sourcecontrolboards,whichvirtuallyalwaysworkwiththecommonsoftware
programs,butitcanbethecasewithsomeproprietarysoftwareandcontrolboards.
Sowhenshouldyouworryaboutthecontrolboard,ifever?Therearegenerallytwoinstanceswherethecontrolboardusedbythe3Dprintermightmakeadifferencetotheuser:whenitcomestoexpandability,andifthesoftwareyoucanuseisconstrained.
WATCH OUT!While it’s usually
possible to replace thecontrol board with a differenttype, you shouldn’t count onit. Changing the controlboard can be complicated bythe enclosure andconnectors used. It’s rarely aplug-and-play type ofchange, even when it ispossible.
Theexpandabilityofthecontrolboardcanbeaprettybigdealifyoueverwanttoupgradeormodifyyour3Dprinter.Ifyouwanttoadddualextruders,aheatedbed,anLCDcontroller,oranythingelse,thecontrolboardhastobecapableofsupportingit.Somecontrolboardssimplydon’thavetheconnectionsnecessarytoaddthesethings.Or,evenifthephysicalconnectionis
present,theremaynotbefirmwareavailablethatsupportsthecontrolofthoseparts.
Softwarecompatibilitycanalsopotentiallybeafairlymajorconcern.Somesoftwarewillonlyworkwithspecificcontrolboards,andviceversa.Thisisusuallyonlythecasewith3Dprintersfrommanufacturerswhowantacomplete3Dprinting
ecosystemundertheirbrand.Theydevelopacontrolboardspecificallyfortheprinterstheymanufacturer,andthenhaveslicingandcontrolsoftwarewhichjustworkswiththosecontrolboards.
Insuchasituation,itmaybedifficultorimpossibletouseanyothersoftwaretoslice3Dmodelsortocontrolthe3Dprinter.Italsomaynotbepossibletousethesoftwareif
youdon’thavethatparticular3Dprinter.Thelatterproblemmaynotbigaverybigdeal,becausethereareplentyofsoftwareoptionsthatarefreeandworkwell.Buttheformerproblemcouldbeprettyserious.Ifyoudon’tlikethesoftwarereleasedbythemanufacturer,you’dstillhavetouseitanyway.Ifthemanufacturerwentoutofbusinessorstoppedsupportingthesoftware,you
maybestuckusingoutdatedsoftware.
Ifeitherofthesethingssoundslikesomethingthatmightmattertoyou,it’sagoodideatodoalittleresearchaheadoftimeaboutwhatyou’regetting.Doesthecontrolboardallowyoutoaddupgradeslater?Areyoufreetousewhateversoftwareyoulike,orareyoustuckwithaparticularprogram
madebythemanufacturer?Dependingonyourneedsandexpectations,thosecouldbemajorfactorsinyourdecisiononwhich3Dprintertopurchase.
SD CardSupportOneniftyadd-onthatmany
controlboardscantakeadvantageofissecuredigital(SD)cardsupport.Normally,youhavetohaveacomputerconnectedtoa3Dprinterwhileitruns.Thisissothehostcontrolsoftwarecansendtheinstructionstotheprinter,whichtellsitwhattodotocreatethepart.However,thoseinstructionsarecreatedaheadoftimebytheslicingsoftware.Allthehostsoftwaredoesiscontrol
thesetupoftheprinter(likehomingtheaxesandheatingthehotend)andthensendtheinstructionsviaUSBtothe3Dprinter.Atthispoint,thecomputerisn’treallydoinganyprocessing,otherthanwhatittakestorunthecomputeritselfandthesoftware.Allit’sdoingisstoringtheinstructionsontheharddriveandthensendingeachcommandtotheprinter.
Becausenosignificantprocessingisbeingdone,thecomputerreallyisn’tnecessaryaftertheslicinghasbeendone.Instead,theinstructionscanbesavedtoanSDcardandthecontrolboardcanreadtheinstructionsdirectlywithouthavingtouseacomputerasanintermediary.Somecontrolboardshavethisfunctionalitybuiltin,whileotherscanhaveitaddedasan
upgradelater.(Somecontrolboardsdon’thavethisabilityatall,butluckily,they’reintheminority.)
Using an SD CardIfthecontrolboarddoescomewithSDcardsupport,orithasbeenadded,youcanforgotheuseofacomputerentirelyduringprinting.Youstillhavetouseslicing
softwareonthecomputertoconvertyour3Dmodelintoaseriesofinstructionsthatcanbereadbythecontrolboard.Butoncethoseinstructionshavebeencreated,youdon’thavetouseacomputeratall;youcansimplysavetheinstructionsfromtheslicingsoftwareontheSDcardandtheninsertitintoaslotonthecontrolboard(oraseparateboard,ifSDcardsupportisadded).
HOT TIPIf your control board
does support SD cards,make sure you do a littleresearch on what kind itsupports. SD cards come indifferent physical sizes, andyou need the right size foryour SD card reader.Additionally, they come indifferent storage capacities,and some might not becompatible with the controlboard if they are too large.
Whenthe3DprinteristurnedonwithanSDcardinserted,thecontrolboardwillautomaticallylookfortheinstructionscreatedbytheslicingsoftware.Ifitfindstheinstructions,itwillproceedwithrunningthem.Generally,theinstructionsincludeinformationonwhattemperaturethehotendandheatedbedaresupposedtobeandanyhominginstructions.Sothe3Dprinterwillstart
withthosethings,andonceit’sheateduptothepropertemperatureandhominghasbeendone,itcanstartprinting.
Fromthenon,it’sjustlikeifyouwereprintingfromyourcomputer,becauseit’sreadingtheexactsameinstructionsfromtheSDcardthatthecomputerwouldhavebeenfeedingtoitoverUSB.
Benefits of SDCardsSDcardsupporthasanumberofbenefitsthatmightproveveryuseful.Thereistheobviousbenefitofnothavingtoleaveyourcomputerattachedtoyour3Dprinterwheneveraprintisrunning.Thatway,youcanuseyourcomputerforotherthingswhileyour3Dprintingis
printing.Youdon’tevenhavetohavethecomputerinthesameroom(orevenbuilding)asthe3Dprinter,becausetheprinteronlyneedstheSDcardtorun.
Italsomakesprintingmorereliable,becausethecomputerisnolongerpartoftheequation.AnyonewhohaseverhadalongprintruinedbecauseWindowsUpdatedecidedtorestartthe
computerknowshowvaluablethatcanbe.ThesamebenefitappliesforthoseofuswhohavedogsthatliketopulloutUSBcables.
Forpeoplewhoareeco-conscious(orbudgetconscious),havingSDcardsupportmeansyoudon’thavetowasteelectricityrunningyourcomputer.Ifyou’refrequentlydoinglongprints,thiscanactuallybepretty
significant.Leavingyourcomputerrunningfortwodayswhileyour3Dprintermakessomebigobjectcanusequitealotofpower.
LCDControllersAsbeneficialasSDcardsupportis,itdoespresenta
coupleofchallenges.Becauseitcanonlyreadinstructionsthathavealreadybeencreatedbytheslicingsoftware,thatmeansyoustillcan’tmanuallycontroltheprinterwithoutacomputer.Thereisalsonowaytochoosefrommultipleinstructionfiles,whichmeansyoucanonlystoreonefileontheSDcardatatimetoprint.
Luckily,thereisasolution
forthat:anLCDcontroller.AnLCDcontrollercombinesanLCDpanelfordisplayinginformation,aswellassomesortofcontrolmechanism(oritcouldbeatouchscreenLCD).ManyLCDcontrollersalsointegrateanSDcardreaderorcanbeusedwithaseparateSDcardreader.Ineithercase,theresultisthesame:youcanmanuallycontrolthe3Dprinterandselectspecificfilesfromthe
SDcardtoprint.
AnLCDcontrollerwithSDcardsupportmadebyRepRapDiscount.
Whena3DprinterisequippedwithanLCDcontroller,youcanmanuallymovethesteppers(including
theextruder)andheatupthehotendandheatedbedwithoutusingacomputeratall.WhenanSDcardisinserted,youcanmanuallyselectwhichfilesyouwanttoprintaswell.SoyoucanloaduptheSDcardwithmanyfilesandchoosewhichoneyou’dliketoprint.
ThismakesanLCDcontrollerveryusefulinsituationswhereyoudon’t
haveacomputernearby.Forinstance,attradeshowsandconventions,youcouldbringthe3DprinterwithanSDcardfullofexampleprints.Youcouldthenhaveyour3Dprinterchurningoutpartsataboothwithoutevenhavingtobringacomputer.
It’salsousefulinsituationswherea3Dprinterissharedbetweenmultiplepeople,likeataschool.Studentscanuse
theirowncomputerstoslicemodelsandthenloadthefilesontoanSDcard.ThestudentscanthenloadtheirfilesfromtheSDcardwithouthavingtohaveacomputerdedicatedtocontrollingtheprinter.
FASCINATING FACTWhat if everything
could be handled by the3D printer without havingto touch a separate
computer at all? This isterritory that is just startingto be explored. A smalltouchscreen computer canbe mounted on the 3Dprinter, allowing you todownload 3D models, slicethem, and print themwithout ever touching yourcomputer.
This is still a pretty newtechnology, but many 3Dprinter manufacturers areworking on integrating it intohigher-end 3D printers. It
isn’t cheap, of course, butwith the popularity of tablets,it’s not as expensive as youmight think. And theusefulness of such a setupis so high that it’s likely tobecome commonplace in thenext few years.
The Least YouNeed to Know
Endstopsarenecessaryfor
tellingthe3Dprinterwheneachaxishasreacheditsendpoint.
Mechanicalandopticalendstopsarebyfarthemostcommon,butanytypeofproximitysensorcouldtechnicallywork.
Thecontrolboardisresponsibleforinterpretingtheinstructionscreatedbytheslicingsoftwareandforusingthoseinstructionstocontrolallofthecomponentsofthe3Dprinter.
Someadditionaldevices,likeLCDcontrollersandSDcardsupport,canbeaddedtocontrolboardstoimprovetheirfunctionality.
CHAPTER
10
Choosing a3D Printer
In This Chapter
Openvs.closedsource
Whethergettinganassembledprinter,printerkit,orDIYprinterisrightforyou
Whatareyourprintingneeds?
DesignsbeyondCartesianprinters
Nowthatyouknowthedifferentpartsthatmakeupa3Dprinter,it’stimetothinkaboutwhattypeof3Dprinterisrightforyou.Decidingon
what3Dprintertopurchasecanbebothoverwhelmingandexciting.Theincreasinglyabundantnumberofmanufacturersandmodelsonthemarketaresuretomakeanyonedizzy.Doyouneeda1.75mmor3mmhotend?Isonecompanybetterthananother?Shouldyoucareaboutwhetherornotit’sopensource?
Thereareaplethoraof
optionsandfactorstothinkabout,butifyoucanmakeafewearlydecisions,you’llgainalotoffocusinyoursearch.Mostpeoplealreadyhaveanideaofwhattheywantandexpectfromtheirprinter,soit’sjustamatterofconsciouslydecidingwhat’simportanttoyou.
Inthischapter,Itakeyouthroughsomethingsyoushouldconsiderwhen
purchasinga3Dprinter.Onceyou’venarrowedyourlistdowntoafewmodels,thechoicewillbecomeasimplematterofpickingwhichhasthebestreviewsandprice.
Open orClosed?Doyoucareiftheprinteris
opensource?Formanypeople,thisisthemostimportantfactorintheirpurchase.Forothers,it’slargelyirrelevant.Theconsumer3Dprintermarketisdividedroughly50/50betweenopen-sourceandclosed-sourceprinters,sochoosingwhichkindyouwantinitiallycancutdownyouroptionsbyhalf.
What Does It Meanto Be OpenSource?LetmefirstexplainwhatImeanby“opensource.”IfyourecallfromChapter2,thebasicopen-sourceconceptissimple:intellectualpropertyissharedfreelysootherscanmodifyit,useit,andshareitthemselves.Thisisindirect
oppositiontothepracticeofcontrollingintellectualpropertyviapatentsandcopyrights(otherwiseknownasclosedsource).Open-sourcedatacanstillbepatentedandcopyrighted,buttobeconsideredopensource,ithastobelicensedtoallowsharing.
DEFINITIONIntellectual
property is any idea that islegally protected. Providinglegal protection for intangiblethings like ideas is acomplicated matter, and thelaws vary from country tocountry. But in the UnitedStates, intellectual propertylike inventions, music,copywriting, patents, and soon are legally protectedproperty.
Intheearlydaysofthe
internet,manypeoplebelievedthatpatentsandcopyrightsoftechnology,especiallysoftware,werecounterproductiveandinhibitedprogress.Bothindividualsandcorporationspushedtheideayoucouldshareyourideaswhilemakingaprofitandfuelinginnovation.
In1985,theFreeSoftwareFoundation(FSF)wascreated
tosupportandpromotethismovement.Atthetime,theprimarygoalwastoensurepeople’sfreedomtousetheirhardwareastheypleasedwithoutbeingrestrictedbyproprietarysoftware.Overtime,thisideologyevolvedtoencompassabroaderideaofopensoftware.Then,in1998,theOpenSoftwareInitiative(OSI)wascreatedwithverysimilargoalsinmind.Together,theseorganizations
(andothers)havehelpedtocreatethemanyfreeandopensoftwareoptionsweenjoytoday.
Butitdoesn’tstopwithjustthesoftware.Amorerecenttrendistheopenhardwaremovement.Theidealsaresimilar,butinsteadofdevelopersmakingtheirsourcecodepublic,engineersaremakingtheirdesignspublic.Inthesamewayyou
candownloadLinuxsourcecodeundertheGNULicensecreatedbyFSF,youcandownloadblueprintsanddesignfilesfromopenhardwarecompanies.TheentireRepRapprojectisbasedonthatideaandhasbeencompletelyopensourcefromtheverybeginning.Infact,manyofthe3DprintersonthemarkettodayareRepRapdesignsorderivatives.
Additionally,othermanufacturershavedevelopedtheirowndesignsindependentlyoftheRepRapprojectbutalsohavemadethemopensource.Forexample,AlephObjectsmakestheonly3DprintertocarryahardwarecertificationfromtheFSF.Thatprinter,theLulzbot,istheprinterfeaturedinthephotosthroughoutthisbook.Thekindofinformationmost
companieskeepunderlockandkey,suchasdesignfilesanddocumentation,ismadefreelyavailablebyAlephObjects.
TheLulzbotTAZ4istheonly3Dprinteravailablethatiscertified
bytheFSF.
Manyothermanufacturersstaytruetotheopen-sourceideologyaswell.LikeAleph
Objects,theymaketheirdesignandengineeringdocumentsavailabletothepublic.Thekeyistheysharetheirdesigns,maketheirprinterscompatiblewithopen-sourcesoftware,andallowcustomerstousetheirprintershowevertheywish.
Why It Might Matterto You
Younowknowwhatitmeanstobeopensource,butwhyshoulditmattertoyou?Whatdifferencewillitmake,practicallyspeaking?
Thebiggestargumentforthepurchaseofanopen-sourceprinterisfreedom.You’llhavethefreedomtousewhateversoftwareyoupleaseandtomodifyyourprinterhoweveryoulike.Youwon’tberestrictedinwhatyoucan
andcan’tprint,whereyourfilescomefrom,orhowyouusethem.Ifyoudecideyoudon’tlikethesoftwarerecommendedbythemanufacturer,youcanjustswitchtoanotherprogram.Youwon’tberequiredtouseproprietaryfilamentcartridgesorberestrictedtoapprovedaccessories.
HOT TIPMany 3D printers with
closed-source hardware arestill capable of using open-source software for slicingand control. Open-sourcesoftware may even berecommended by themanufacturer. When you’relooking at printers, be sureto check which software themanufacturer recommendsand whether you’re free touse other software.
Withallofthatsaid,therearemanygreat3Dprintersonthemarketthatarenotopensource.Youmaydecidetheprinterforyouisclosedsource.Thereisabsolutelynothingwrongwithgoingthatdirection.Afterall,thevastmajorityofthingswebuyonaday-to-daybasisaren’topensource.Mostcompletelyclosed-sourcemanufacturersstrivetomaketheirsystemsseamlessand
easytouse,andyoumayfindthatyoupreferoneofthosesystems.Butbesuretoconsiderthedecisioncarefully,sinceclosedsourceismorerestricted.
Assembled,Kit, or DIY?Thenextfactortoconsideris
howyouwanttoreceiveyourprinterfromthemanufacturer,orifyouwanttoskipthemanufactureraltogetherandbuildyourown3Dprinter.Thischoiceshouldn’tbetakenlightly,soI’mgoingtoexplaintheadvantagesanddisadvantagesofeachoption.
Assembled 3D
PrintersIfyouareunsurewhatyouwanttodo,thisisabsolutelythesafestchoice.Purchasingyourprinteralreadyassembledfromthefactoryistheeasiestandmostreliablewaytostartprinting.Youwon’thavetoworryaboutassembly;youcanjustunboxit,doafewsetupsteps,andbeprintingyourfirstmodelinanhourortwo.Andmost
assembledprinterswillcomewithawarrantyofsomekindincaseanythinggoeswrong,whichmaynotbethecasewiththeotheroptions.It’salsolikelythatyou’llbeabletoreceivesometechnicalsupportifyourunintoanyproblems.
Costisthebiggestdownsidehere.Someonehadtobepaidtoassembletheprinter,andthatresultsinahigherprice.
Shippingcostsmaybehigheraswell,astheboxwillusuallybebiggerthanthatofanunassembledprinter.And,althoughit’sassembled,you’llprobablystillneedtodoalittlebitofadjustmenttogetitactuallyprinting.
3D Printer KitsKitsareagreatwaytosavesomemoneyandan
opportunitytolearnaboutyourprinterasyou’rebuilding.Theknowledgeandexperienceyougainbuildingtheprintercanhelptremendouslyinthefuturewithtroubleshootingandmodifications.
Generally,akitwillincludeallofthepartsandhardwareyouneedtobuildyourownprinter.Itshouldcomewiththeframepieces,fasteners,
electronics,motors,andanythingelseyou’llneedtobuildaworking3Dprinter.MostkitsonthemarkettodayarebasedonRepRapdesigns,buttherearesomethatwereindependentlydesigned.Likewithanassembledprinter,yourdecisionshouldbebasedonyourneeds,butyou’llalsoneedtotakeintoaccountbuildtimeanddifficulty.
Whatittakestobuildakit
canvaryquitealot.Somekitscomepartiallyassembledandjustrequirethatyoufitthepiecestogether.Otherkitswillrequirethatyouassembleeachandeverypartonyourown,soyoumayneedspecialskills(liketheabilitytosolder).Youmayalsohavetheoptionoforderingapartialkitthatincludeseverythingexcept3D-printedparts,whichcanbeagoodwaytosavesomemoneyif
youknowsomeonewhocanprintthosepartsforyou.
Thedownsidestokitsarethattheycanbeverytimeconsumingtoassemble,theyrequiretools,andassemblycanbedifficult.Therefore,makesureyou’reconfidentinyourabilitytoassembletheprinterbeforeyoupurchaseit.
Building a DIY 3D
PrinterAnotheroptionistobuildyourowndo-it-yourself(DIY)printerusingdesignspublishedbyindividualsoropen-sourcecompanies.MostofthesedesignsarebasedontheRepRapproject,andmanyaretriedandtrue.Buildingyourownprintercansaveyouasignificantamountofmoneyandgivesyoutheopportunitytomodify
thedesigntobuildtheexactprinteryouwant.(SeeAppendixBforsomehelpfullinksonhowtodothis.)
MyDIY3Dprinter,basedontheopen-sourceTAZdesign.
Thedownside,ofcourse,isthatit’scompletelyuptoyoutosourceallofthepartsandputthemtogether.Thisisa
verydifficulttask,andIwouldn’trecommenditforyourfirstprinter.Butforasecondprinter,orfortheadventurous,itcanbeveryrewardingandagreatlearningexperience.
DeterminingYour Needs
Atthispoint,yourchoicesshouldalreadybeconsiderablynarrowed,andhopefullyafewmanufacturersandmodelsarestartingtostandout.Whenlookingattheseremainingmodels,considerwhatyourneedsareandwhatyouneedyourprintertodoforyou.Whatkindofmodelswillyoubeprinting?Whatwilltheirusebe?Whatkindoffilamentwillyouuse?Whatshould
everythingcost?Thefollowingareafewspecificthingsyou’llwanttopayattentionto.
HOT TIP3D printer
manufacturers willsometimes publishspecifications in inches,millimeters, or both, so youmay have to do some unitconversions whencomparing printers.
However, metric units(millimeters specifically) aregenerally the standard whenexporting and importing STLfiles and when configuringparameters in software andfirmware. Be sure to checkwhat units are used andrequired when working withdifferent 3D printers.
Print VolumePrintvolumeisthe
specificationthattellsyouhowlargeamodel(ormodels)youcanprint.Inmostcases,thiswillberectangular,andiscalculatedbymultiplyingtheprintwidth,length,andheight.However,forsomeprinters(particularlyDelta-styleprinters),theprintvolumeiscylindricalandcalculatedbymultiplyingpibyradiussquaredandheight(πr2h).IfyoudochooseaDeltaprinter,
besurethecircularbaseissuitableforyourneeds.Whilelookingattheprintvolumeiscertainlyausefulwayofcomparingprinters,itdoesn’tquitetellthewholestory.Twoprinterswiththesameprintvolumecouldhavevastlydifferentdimensionsthatmightaffectyourdecision.Forexample,PrinterAhasprintdimensionsof8×8×8inches,whilePrinterB
hasprintdimensionsof16×16×2inches.Bothprinterswillhaveaprintvolumeof512cubicinches,buthowusefulwouldaprinterbethatcouldonlyprintamodel2inchestall,asinthecaseofPrinterB?
Forthatreason,it’sagoodideatolookattheactualdimensions.WhatistheprintsizeintheXdirection?HowaboutYandZ?Determine
thelargestsizeyou’llbelikelytoprint,andmakesuretheprintersyou’reconsideringcanhandleit.
Youmaybetemptedtojustbuytheprinterwiththelargestprintvolume,justincase.Butkeepinmindthatbothcostandprinttimeincreasewithprintvolume.Therefore,thereislittlesenseinpayingalotofmoneyforabigprintvolumeyouwon’t
actuallyuse.Plus,printtimeincreasesexponentiallywithsize(youcanthankthesquare-cubelawforthat).
DEFINITIONThe square-cube
law is a scientific principlethat describes themathematical relationshipbetween size, surface area,and volume. Its relevance to3D printing is the way thatvolume (and therefore print
time) increasesexponentially with size. Forexample, a cube 10mm to aside has a volume of1,000mm3. Doubling thedimensions of the cube to20mm to a side results in avolume of 8,000mm3.Because the larger cube is 8times the volume, it will take8 times longer to print thanthe smaller cube.
Print ResolutionPrintresolutionisessentiallyameasureofthepotentialqualityofyourprintedmodels.Smallerisbetterhere,similartohowsmallerpixelsresultinbetterimagequalityonyourcomputermonitor.Asmallerresolutionmeansyoucanprintfinerdetails,andtheoverallsurfacefinishofthemodelwillbesmoother.But
determiningtheprintresolutionthataprinteriscapableofcanactuallybeatrickytask.Thereiscurrentlynopracticalwayofspecifyingtheactualeffectiveprintresolutionofa3Dprinterintherealworld.
Theoreticallyspeaking,printresolutionshouldbetheresultoftwofactors:nozzlesizeandmovementprecision.Thenozzlesizedetermineshow
finethefilamentthreadbeingejectedfromthehotendis.Becausenozzlesarereplaceable,thisisn’tsomethingyoushouldbetooconcernedwith—youcanalwayschangethenozzletoonewithasmalleropening.However,movementprecisioncan’tbealteredwithoutsignificantmodificationtotheprinter’shardware,makingitanimportantconsideration.
Thiscanbecalculatedwiththe“stepspermm”information,whichshouldbeprovidedbythemanufacturerforusewhenconfiguringyourslicerandfirmware.Forinstance,ifyourXaxisis200stepspermm,yourmovementprecisiononthataxisis0.005mm(1mmdividedby200).Butnomatterhowprecisethemovementis,thenozzlesizewillrestricthowdetailedyour
printscanbe.Ifthenozzleistoobig,itwon’tbeabletoprintveryfinedetail.It’sanalogoustotryingtowritesmalltextwithamarker—themarkerisjusttoobigtowritefinedetails.
Thereareotherconcernsthatfactorintotheresolutionofa3Dprinterthough.Justsomethingthatseemsrelativelyminor,likeflexintheprinter’sframe,can
reducetheeffectiveresolutionoftheprinter.Thismeansthattheresolutionspecifiedbythemanufacturermightonlybeachievableatslowspeedsunderthebestcircumstances.
FilamentTherearemanyfilamentmaterialsonthemarket,andthechoicesarerapidly
increasing.Different3Dprintersarecapableofutilizingdifferentfilamentmaterials,andit’sworthpayingattentiontothiswhenchoosingaprinter.
IfyourememberfromChapter7,thetwomostcommonfilamentmaterialsinusetodayarePLAandABS.PLAiswidelyconsideredtoyieldhigher-qualityprints,whileABSpartsaregenerally
strongerandmoredurable.ABSisalsoeasiertoworkwithpostprint(forsanding,drillingholes,andsoon).VirtuallyallFFF3DprintersareabletoprintwithPLA,whileABSrequiresaheatedbedtoprintsuccessfully.Ifyoupurchaseaprinterwithaheatedbed,you’llbeabletoprintthetwomostpopularmaterials.However,3Dprintersthatdon’tcomewithaheatedbedincludedwill
oftenhavethatasanaccessoryspecificallytoallowyoutoprintABS.
Othermoreexoticmaterialsmayrequirespecializedhardware.Forexample,ifyou’reinterestedinprintingflexiblefilament,aprinterwithaBowdenextruderwillnotwork.Thefilamentsimplybendstoomuchinthefeedtubeandwon’tbeabletofeedreliably.Soyou
shouldonlyconsiderdirectfeedextrudertypesifyouwanttoprintflexiblefilament.
DEFINITIONFlexible filament is
an umbrella term for anyfilament material that isflexible, rubbery, andsquishy. This can be usedas an alternative to the hardand rigid plastic that is morecommonly used for 3D
printing. The exactcomposition differsdepending on themanufacturer, but theresulting material is fairlysimilar with all of them.
Othermaterials,likepolycarbonate,requirespecialhardwaretoprint.InChapter18,I’llgointoalotmoredepthaboutwhatothermaterialsareavailableand
whatkindofhardwareyou’llneedtousethem.It’sworthskippingaheadtothatchapterifyou’recuriousaboutsomeofthemoreuniquematerialsandwanttoknowwhatyou’llneedtoprintwiththem.
Besidesfilamentmaterial,youalsoneedtodecideonwhatfilamentsizeyou’dliketobeabletouse.Currently,3Dprinterfilamentcomesintwosizes:1.75mmand3mm.
Originally,mostfilamentcamein3mm.Asnozzlesizesdecreased,however,ittookmoreforcetopush3mmfilamentthroughthenozzle.Forthatreason,1.75mmhasbecomethemorepopularchoice,withawiderangeofmanufacturersandcoloroptions.However,flexiblefilamentsgenerallyfeedmorereliablyin3mmbecausethethicknessincreasesthestiffness,makingitlesslikely
tobendandjam.Somefilamentmanufacturersonlyselltheirflexiblefilamentsin3mmduetothat.
Withallofthatsaid,both1.75mmand3mm3Dprinterswillhaveaverywideselectionoffilamenttochoosefrom.Don’tputtoomuchweightonthisfactor;rather,firstfinda3Dprinteryoulike.Ifthatprinterhasanoptionof1.75mmor3mm,
decideonasizebasedonyourneeds.
PricesUntiljustafewyearsago,thehighcostof3Dprintersmeantthatusuallyonlycorporationscouldaffordtopurchasethemforprototypingpurposes.Luckilyforbothhobbyistsandsmallcompanies,3Dprinterprices
haverecentlydroppeddramatically.Inaveryshortamountoftime,theleastexpensiveprintershavegonefrombeingtensofthousandsofdollarstojustafewhundred.Evenbetter,acurrentmidrangeconsumerprinteriscapableofrivalingthequalityandprintvolumeofprofessional3Dprintersfromonlyafewyearsago.
Sowhatcanyouexpectto
payforaconsumer3Dprinterforpersonaluse?Obviously,pricewillvarydependingonsizeandfeatures,butprovenandwell-reviewedprintersrangefromabout$400to$3,000.Atthebottomend,youhaveverybasicprinterswithsmallprintvolumesthatareoftenconstructedoutofinexpensivematerialslikewood.Aspricesrise,printvolumegenerallyincreases,morefeaturesareadded,and
framesaremadeofhigher-qualitymaterials.Atthehighendoftheconsumermarket,youhave3Dprintersthatwouldevenbesuitableforanengineeringorprototypingenvironment.
Simplyput,thisisanexcitingtimetopurchasea3Dprinter!Pricesarelowenoughthatit’srealisticforanaveragepersontopurchaseoneforhomeuse.Themarketisvery
healthy,andthereareoptionsouttheretosuitavarietyofneeds.
HOT TIPWhen thinking about
cost, remember to keeproom in your budget fortools, accessories, andfilament as well. Filamentprices range from about $25to $50 per kilogram for ABSand PLA, and a kilogramshould be enough for you to
get started with. It’s also agood idea to have a basicset of hand tools available—such as wrenches, pliers,and screwdrivers—alongwith various glues andtapes.
Printers withUnusual
DesignsForthepurposesofsimplifyingthisguide,I’vebeentalkingprimarilyaboutCartesian3DprintersthatuseFFFtechnologyforprinting.Cartesianprintersaresetupwitharectangularbuildareawithmovementinthreeaxes,andarebyfarthemostcommontypeofprinteronthemarket(seeChapter5).
However,thereareotherkindsofprintersouttherewhichyoumightcomeacross.OnetypethathasgainedalotofpopularityrecentlyistheDelta-style3Dprinter.Theseuseauniquemethodofmovementwherethebuildplatformisstationaryandthehotendismovedonthreearmsattachedtoverticalrails.Deltaprintersareadvantageousbecausethey’recapableofprintingat
higherspeeds.However,beinganewerdesign,thereislessinformationandsupportavailable.Theyalsohaveacircularbuildplatformasaresultoftheiruniquegeometry,whichmightnotsuityourneeds.
ThisisaDelta-styleRostock3Dprinter,aRepRapdesign.
Anotherdesignthathasrecentlystartedtoentertheconsumermarketisdigitallightprocessing(DLP).Traditionally,thesetypesof3Dprinterswereexpensiveandthetechnologywasonlyusedinprofessionalprinters.Butpriceshavedroppedlowenoughthattheycouldbeworthconsidering.DLP
printersworkbyshininglightontoavatofUV-curableresin.Asthelighthitstheresin,itcuresandhardens,eventuallyresultinginaplasticpart.
DLP3Dprintersarecapableofproducinghigh-qualitypartswithveryfinedetail,buttheyalsohavesignificantdrawbacksthatmakethemunattractiveoptionsoutsideofspecializeduses.Theresin
usedismuchmoreexpensive(perkilogram)thantraditionalfilament,andtheselectionismuchsmaller.Plus,colorandmaterialoptionsareonlyasmallfractionofwhatisavailabletoFFFprinters.They’realsounabletoprinthollowparts,astheuncuredresinisleftinsidethepart.
InadditiontoDeltaandDLP3Dprinters,therearea
numberofothermoreexoticdesignsoutthere.However,theyareallfairlyexperimentalatthispointandprobablywouldn’tbeagoodchoiceforyourfirst3Dprinter.Infact,it’sprobablybesttosticktoaCartesianprinterunlessyouhaveaspecificneedforoneoftheothertypes.ThepopularityofCartesianprintersensuresthatyou’llhaveaccesstoawealthofinformationandsupport,as
wellasawiderangeofchoices.
The Least YouNeed to Know
Makesureyouconsideryourpresentandfutureneedswhendeterminingwhatprintertobuy.
Choosinganopen-source3Dprinterprovidesbenefitsforsupport,flexibility,and
modifications.
Priceshavedroppeddramaticallyinrecentyears,but3Dprintersarestillaheftyinvestment.Kitsoffersavingsandanopportunitytolearntheinsandoutsofyourprinter.
Ifyou’renewto3Dprinters,it’sbesttostickwiththepopularCartesianprinter.Thatway,you’llhaveaccesstoplentyofsupportandinformation.
PART
3
Setting Upand PrintingNowthatyou’refamiliarwithhow3Dprinterswork,it’stimetogetintotheiractualoperation.Inthispart,Igo
overhowtosetupyour3Dprinter’shardwarewhenyoureceiveit.Ialsoteachyouhowtoconfigureyoursoftwareandconnecttoyourprinter.
YoualsolearnimportantthingslikehowtolevelthebedandhowtoadjusttheheightoftheZaxis.Ithenfinishthispartwithsomebasicprintingprojectstogetyoustarted.
CHAPTER
11
SoftwareSetup and
Printer Control
In This Chapter
Thepurposeoffirmwareandhostsoftware
Howslicingsoftwareworks
CommonhostcontrolcommandsandusefulG-code
Beforeyoucanactuallyprintanything,youhavetosetupthesoftwaretoslicemodelsandcontrolthe3Dprinter.
Therearemanyoptionsfortheseprograms,andit’spossiblethatyour3Dprintermayberestrictedtooneparticularsoftwarepackage.However,thesettingsandsetupprocesstendtobefairlysimilarbetweenallofthem.
Inthischapter,youlearnaboutyourprinter’sfirmware,aswellashowtochoosehostandslicingsoftware.Ithendiscusshow
youusethissoftwaretoconnecttoandcontrolyourprinter.
FirmwareExplainedFirmwareisbasicallyaprogramthatisstoredonadevice.Iknowthatsoundsterriblyvague,butthat’s
becausethespecificsvaryquiteabitdependingonthedevice.Forexample,onyourcomputer,theoperatingsystemisnotfirmware,buttheBasicInput/OutputSystem(BIOS)is.Onacellphone,however,theentirecellinterfacemayrunonfirmware,orthefirmwarecouldjustbeusedtoloadanoperatingsystemlikeyourcomputer.
Thekeycharacteristicsoffirmwarearethefollowing:
It’salwaysthefirstthingtorunwhenthedeviceisturnedon.
It’snotstoredinmassstorage.Instead,it’sstoredonanonboardchipthat’salwayspresent,sincedevicescan’tfunctionwithoutit.
It’salmostalwayssetupforonlyonespecificdevice.
DEFINITIONThe Basic
Input/Output System(BIOS) is the firmwareinterface used on mostcomputers. It’s the first thingto load as soon as yourcomputer starts up andcontrols how the operatingsystem (Windows, forexample) is booted.
Firmwareisdifferentfrom
software,thoughinaverygeneralwaytheyappearsimilar.Thinkofitasbeingasseriesoflayersbuiltontopofeachother:thefirmwareloadsfirstanddirectlycontrolsthehardware,andthenthesoftwareloadsandonlycontrolsthehardwareindirectlyviathefirmware.Becausethefirmwarecontrolsthehardwaredirectly,ithastobewrittenforthespecifichardware
beingused.Thisallowsthesoftwaretobemuchmoregeneric(andtoworkwithawiderangeofdevices),becauseit’snotdirectlyinterfacingwiththehardware.
In3Dprinting,thefirmwareisstoredonthecontrolboardandisusedforthecompleteoperationofthe3Dprinter.Nosoftwareisneededontopofthefirmware,andallofthefunctionsofthe3Dprinter
arecontrolledbythefirmwarerunningonthecontrolboard.Despitethecomplexityof3Dprinters,thesoftwareneededtocontrolthemisstillsmallenoughtobeloadedasfirmwareontotheread-onlymemory(ROM)ofthecontrolboard.
BecausefirmwarehastobesmallenoughtofitinROM,it’sgenerallywrittentobeassmallaspossible.Thesmall
sizecombinedwiththebase-leveloperationoffirmwareusuallymeansitcanonlyworkwiththespecifichardwareitwasdesignedfor.Ifthehardwareischanged,thefirmwarehastoberewrittenforthathardware.
Inthecaseof3Dprinters,therearemanytypesofprinters,withmanytypesofcontrolboards.Luckily,they’redesignedsimilarly
enoughthatthesamebasicfirmwarecanbeusedforalotofthem.Thefirmwarejusthastobeproperlyconfiguredforthecontrolboardit’sloadedon.Thatconfigurationcanbeperformedbytheprintermanufacturerorevenbytheuser.However,othercontrolboards—especiallyonesthataren’topensource—canonlybeloadedwithfirmwarereleasedbythemanufacturer.Ifthat’sthe
case,theuserhastorelyonthemanufacturertoprovideadequatefirmware.
FASCINATING FACTThere are only a few
basic firmware systems thatare used for the majority of3D printers (especially open-source 3D printers). This ispossible because thehardware used for 3Dprinters is so similar for mostmodels. As long as the
control board is compatible,the firmware just has to beconfigured for the specifichardware being used.
Still,3Dprintercontrolboardsalmostalwayshavefirmwarethatissomewhatconfigurableevenafterithasbeenloaded.Thisissotheusercanadjustthesettingsforthingslikethesizeoftheprinter,howmanystepsit
takestomoveeachaxis1mm,andsoon.Thisinformationisstoredintheelectricallyerasableprogrammableread-onlymemory(EEPROM)andcanbechangedandoverwritten.
Ifnewfirmwareisflashed(essentiallyinstalled)ontothecontrolboard,thedatastoredintheEEPROMisstillkept,sothesettingsremain.Thisisgoodforwhenyou’re
justupdatingfirmware,butkeepinmindthatiftheEEPROMsettingsareincorrect,theywillstillpersist.Ifyounoticesomeproblemdoesn’tgoawayevenafterflashingnewfirmware,you’llprobablywanttomakesureitisn’tsomeEEPROMsettingthatiscausingtheproblem.
Unlessyouhaveaproblemwithit,though,thereis
usuallynoreasonwhyyouneedtodoanythingwiththefirmwareunlessyouwantto.Occasionally,manufacturerswillreleasenewfirmwareversionsthateitherfixabugoraddafeature,butforthemostpart,thefirmwareisn’tsomethingyouneedtoworryaboutasauser.
Choosing
HostSoftwareUnlessyouhaveanLCDcontroller(seeChapter9),youneedhostcontrolsoftwaretomanuallycontroltheprinterandrunprints.Thehostsoftwareiswhatcontrolscommunicationbetweenyourcomputerandyour3Dprinter.
Thehostsoftwareconnectstothe3Dprinter’scontrolboardviaUSB.Whenyoustartaprint,thehostsoftwaretakesthecommandsgeneratedbytheslicingsoftwareandsendsthemovertheUSBconnectiontothe3Dprinter.Thenumberofindividualcommandscaneasilynumberinthethousands,andeachcommandissentoneatatime.Oncethecommandhasbeenperformed,the3D
printer’scontrolboardreturnsaconfirmationtothehostsoftware,whichthensendsthenextcommand.Thesestepsarerepeatedoverandoveragainuntiltheprintisfinished.
Some3Dprintermanufacturersrequirespecifichostsoftwaretocontroltheirprinters.Inmostcases,however,youcanchoosefromavarietyofhost
software,includingRepetier,Cura,ReplicatorG,andPronterface.Alloftheseperformthesamegeneralfunctions:manualcontrolofthe3Dprinter,sendingcommandstorunprints,andusuallyintegrationofslicingsoftware.YoucanalsomodifyEEPROMsettingsviathehostsoftware.
HOT TIP
Because eachcommand is sent oneat a time, the USB
connection has to remainestablished throughout theentire printing process. If theUSB cable is unplugged, thehost software is closed, orthe computer is turned off,the printing will stop and thepart will be ruined. For thisreason, you should makesure your computer isrunning throughout theentire print. More than onepart has been ruined by a
Windows Update restartingthe computer halfwaythrough the print.
Repetierhostsoftware,withSlic3rintegrated.
ChoosingSlicing
SoftwareEvenifyour3DprinterhasanLCDcontrollerandhostsoftwareisn’tneeded,you’llstillhavetosliceyour3Dmodelsforprinting.That’swhatslicingsoftwareisfor:toconvertyour3DmodelsintoaseriesofG-codecommands.Thisisacomplextaskthatrequiresalotofprocessingpower,sofornow
it’snecessarytodotheslicingonacomputer.
DEFINITIONG-code is the
programming language that3D printers and othercomputer-controlledmachine tools can use forinstructions. The G-code iswhat is used to give most 3Dprinters the commands theyfollow to produce parts. I’llgo into more detail on G-code later in this chapter.
Unlikehostsoftware,theslicingsoftwareyouusecanactuallymakeaprettybigdifferenceinhowyourprintsturnout.Thisisbecausetheslicingsoftwareiswhatdetermineshowthe3Dprinteractuallymovestocreatethepart.
Slicersusealgorithmstobreakdowna3Dmodelintoaseriesofstepsforthe3Dprintertofollow.Those
algorithmsareallprogrammeddifferently,sooneslicerwillproducedifferentcommandsthananotherslicerwould.Thiscanresultinverydifferentprints,dependingonwhichsliceryouchoosetouse.Somemayproducehigher-qualityprints,somemayprintfaster,andsomemayhandlespecialtasks(likegeneratingsupports)better.
Becausetheslicingsoftwarecanmakesuchabigdifferenceinhowpartsareactuallyprinted,itcancertainlybeworthwhiletotrymultipleslicers.Forexample,someslicersmighthandlethecurvedsurfacesofartisticmodelsbetter,whileothersmightbebettersuitedtoengineeringmodelsthathaveflatsurfacesandrequirealotofsupports.Youmightevenfindthatsomeslicerswork
betterwithyourparticular3Dprinterthanothers.Experimentingwithsomeofthepopularslicerscanhelpyoufindtheonethatsuitsyourpriorities,the3Dprinteryou’reusing,andthekindsofmodelsyou’llbeprinting.
Youcanfindslicingsoftwareintegratedwithhostsoftwareinthesamepackage.RepetierandCuraaretwoexamplesofhostsoftwarethatinclude
slicingsoftwarewiththem.However,slicingsoftwarethat’sseparatefromhostsoftwareisalsoavailable,suchasKISSlicer,Simplify3D,andmanyothers.
Connectingto YourPrinter
Onceyou’vechosenwhichhostsoftwareandslicingsoftwaretouse(oratleasttotry),youneedtoactuallyconnectthehostsoftwaretoyour3Dprinter.Howyoudothisdependsonyourprinter,yourcontrolboard,andthehostsoftwareyou’reusing.
Ifyou’vepurchasedaprinterthatrequirestheuseofproprietarysoftware,Ican’tgiveanyrealspecificson
howtoconnectit.Thegoodnewsisthat3Dprintermanufacturersusuallychoosetouseproprietarysoftwareinordertomaketheuserexperiencefriendlier,soconnectingyourprintershouldbeasimpleprocess.Themanufacturershouldalsoprovideyouwithinstructionsonhowtodoso.
However,ifyoupurchasedaprinterwithanopen-source
controlboard,therearesomestepsyoucanfollowtogetyour3Dprinterconnected:
Gettheproperdriversinstalledforyourcontrolboard.ThedriversgiveyourcomputertheinformationitneedstoestablishaUSBconnectionwithyour3Dprinter.Thesearedriversjustlikeyou’dhavetoinstallwhenyouconnectanyothernewdevicetoyourcomputer,
likeacameraoraninkjetprinter.
Whichdriversyouneedtoinstallnotonlydependonyouroperatingsystem,butalsocontrolboardyou’reusing.Arduino-basedcontrolboards,forexample,needArduinodriversthatcanbedownloadedfromtheArduinowebsite(arduino.cc/en/Main/Software).Checkwiththemanufacturer
ofthe3Dprinterorcontrolboardforthespecificdriversneededforyourprinter.
HOT TIPIf your control board is
Arduino-based, you’llprobably want to go aheadand install the completeArduino software package.This will allow you to modifyand update the firmware inthe future if you choose to,along with providing thedrivers needed to connectthe 3D printer to thecomputer.
ConnectaUSBcablefromthe3Dprinter’scontrolboardtoyourcomputer.YourcomputershouldgivesomeindicationthatitseestheUSBconnectionbutshouldn’ttrytoinstallanything.Ifittriestoinstalldrivers,thedriversmightnothavebeeninstalledproperlybefore;gobacktothefirststeptogetyourdriversinorderandthentryconnectingagain.
OpenyourhostsoftwareandchoosetheCOMport.Somewhereontheinterface,youshouldseeawaytochangetheprintersettingandabuttontoconnecttheprinter.Inthesettings,choosewhichCOMportyour3Dprinterison.ThisshouldcorrespondtowhichUSBportthecableispluggedinto,butthereisgenerallynophysicalindicationofthenumberingusedfortheUSB
ports.
ConnectingtothecorrectCOMportusingPronterface.
YoucancheckyourdevicemanagertodeterminewhichCOMportisbeingusedbythe3Dprinter,butsortingthroughthedevicemanager
canbedifficult,asthedevicesaren’talwaysnamedasyoumightexpect.Instead,itmightbeeasiertotryeachoftheCOMportsifyoudon’thavealotofdevicesconnectedviaUSB.Ifyoudon’tseetheCOMportwhichcorrespondstotheUSBconnectionwithyour3Dprinter,refreshthelistofavailableCOMports.
Onceyou’vefoundthe
correctCOMport,itshouldonlytakeafewsecondsforyourprinterandhostsoftwaretoconnect.
ControllingYour PrinterOncetheconnectionbetweenthehostsoftwareandthe3Dprinterhasbeenmade,you
canmanuallycontroltheprinter.Yourhostsoftwareshouldhaveaninterfacefordoingthis,usuallycalledsomethinglikemanualcontrol.ThisisformanuallysendingG-codecommandstothe3Dprinter’scontrolboard,whichthenfollowsthecommand.(I’llgooverG-codemorelaterinthischapter.)
Mosthostsoftwarehavea
fewbasicmanualcontrolfunctions,themostcommonofwhicharethefollowing:
Jogaxis:Thiscommandisusedtomoveanaxisbyasetamountinaparticulardirection.Themovementdistanceisusuallysetinincrements—like.1mm,1mm,10mm,50mm,and100mm—inboththepositiveandnegativedirections.
WATCH OUT!If you don’t have end
stops on your 3D printer, donot use the homingfunctions. Without end stopsto tell the 3D printer whenthe axis is at its end point,they will keep trying to moveeven when they can’tphysically move any further.This could potentiallydamage your printer.
Homeaxis:Homingmovestheextruder,printbed,orZaxisassemblytoitsendpoint.Whenthisfunctionisused,theprintermovestheselectedaxisuntilitsendstopistriggered.Oncetheendstophasbeentriggered,theprintersetsthecurrentpositionforthataxistozero.
Homeall:Thisfunctionsimplyhomesalloftheaxeswithonecommand.
Generally,ithomeseachaxisoneatatime,notallsimultaneously.
Extrude:Thiscommandisforextrudingasetamountoffilament.You’llgenerallyonlyneedtousethiscommandwhenloadingnewfilamentorwhencalibratingyourextruder.
Retract:Thisistheoppositeoftheextrudecommand.Itrunstheextruderstepper
motorinreverseinordertopullthefilamentoutofthehotend.Often,theextrudecommandandretractcommandarecombined,asretractionisreallyjustnegativeextrusion.
Steppermotorpower:Normally,onceyou’vestartedmanuallycontrollingthe3Dprinter,thesteppermotorsaregivenpower.Evenwhenthey’renotmoving,the
steppermotorsusepowertoholdtheirpositions.Ifyouwanttophysicallymoveanythingconnectedtoasteppermotor,youhavetoturnoffthepowertothesteppermotors,whichiswhatthiscommandisusedfor.
Hotendpower:Thisprovidestheobviouslynecessaryfunctionofturningthehotendonandoffandsettingthetemperatureofthe
hotend.Ifyou’regoingtobemanuallyextrudingfilament,youhavetofirstheatupthehotendtothepropertemperature.
Heatedbedpower:Asyoumightexpect,thisturnstheheatedbedonandoffandallowsyoutosetitstemperature.Therereallyaren’tmanyreasonswhyyou’dneedtomanuallyturnontheheatedbed,butitcan
beusefulforpreheatingthebedbeforeyoustartaprint.
Fanpower:I’mnotsurewhyyou’dwanttomanuallyturnonthefan(otherthantotestitsfunctionality),butifyoudid,youcoulddosousingthiscommand.
TheRepetiermanualcontrolinterface.
G-CodeInadditiontothesecommandswhichusuallyhavebuttons,thehostcontrolsoftwarealsohasawaytosendyourownG-codecommands.Thisisjustasimplecommandlinethatallowsyoutosendacommandandreceiveareturn(ifapplicable).
Ifyourecallfromearlier,G-
codeiswhatthe3Dprinter’scontrolboardactuallyusesforinstructions.Itisalongseriesofcommandsthatcalloutaparticularfunctionalongwithcoordinates,ifnecessary.
Thecommandsareverybasic,andthefunctionalitycomesfromstringingmanycommandstogether.Eachindividualcommandissomethingsimple,liketracea
linefrompointAtopointBordrawanarcwithaspecifiedradiusbetweentwopoints.Butwhenthesesimplecommandsnumberinthethousands,theycanproduceverycomplexparts.
Printing with G-CodeWhenyouuseslicingsoftwaretoslicea3Dmodel,
thatsoftware’salgorithmsanalyzethe3DmodeltodeterminewhatG-codecommandsitcanusetoreproducethemodel.Afterthemodelhasbeenslicedinthinlayers,thesliceristhenleftwithessentiallyatwo-dimensionaldrawing,whichitneedstotracewithG-code.
HOT TIPTechnically speaking,
3D printers don’t have to useG-code. They can use otherinstructions, if that’s whatthey’re programmed to use.In fact, some 3D printermanufacturers do build 3Dprinters that use proprietarylanguages for instructions.However, that’s rare; most3D printers today, especiallyin the consumer market,operate using G-code.
ThesoftwaregeneratesG-
codebasedonrulesdeterminedbythevaluesyouset,alongwiththealgorithmswrittenbytheprogrammer(s)ofthesoftware.Thingslikefilamentsize,extrusionwidth,movementspeed,andsoonareallusedtogeneratethatG-code.OnceacompletesetofG-codeinstructionsisgenerated,theG-codecanthenbefedtothe3Dprinterfromthehostsoftware.
PerformingFunctionsManually with G-CodeAsidefromwhenyou’reactuallyprinting,youcanalsosendG-codecommandstoperformfunctionsmanually,suchaschangingEEPROMvalues,auto-levelingthebed,checkingthestatusoftheend
stops,andsoon.
G-codecommandscanbeenteredmanuallyinthehostsoftwareandsentdirectlytothe3Dprinter.
G-codecommandshaveaverysimplesyntax;allyouhavetodoisenterthecommandname(forexample,
M212)followedbytherequiredvalues,ifnecessary.Ifyou’rejustrequestinginformation,noadditionalvaluesareneededmostofthetime.Ifthecommandallowsyoutoentermultiplevalues,youcanenteranycombinationofthem.If,forinstance,youweredoingahomingcommand,youcouldspecifyifyouwantedtohomeX,Y,Z,oranycombinationofthethree.
TherearehundredsofpossibleG-codecommands,althoughnotallofthemwillworkwith3Dprinters(andsomeofthemmayevenhavedifferenteffects,dependingontheparticularfirmware).Whilethevastmajorityofthemaren’tveryusefulorpracticaltousemanually,thefollowingareahandfulofthemthatmightprovetobehelpfultoyou:
G20(unitstoinches):Youcanusethiscommandtochangethecurrentunitsfromthe(generally)defaultmillimeterstoinches.
G21(unitstomm):Thissetsthecurrentunitstomillimeters,whichisgenerallythedefault.
G28(homing):Thisisusedtohomeanaxisoraxes.Ifjust“G28”isentered,allthreeaxeswillbehomed.
However,youcanenter“G28XZ,”forexample,anditwilljusthometheXandZaxesandskiptheYaxis.
G29(auto-leveling):Ifyour3Dprinterhasaprobe,youcanusethistoauto-levelthebedbyprobingthreepoints.Thisusestheprobetomeasuretheheightofthreecornersofthebedinordertocalculatetheplaneofthebed.This,inturn,canbeusedto
raiseandlowertheZheightthroughouttheprinttokeepthenozzleataconstantdistancefromthebed.
G92(settingcoordinates):Ifyouneedtomanuallytellthe3Dprinterwhatitscurrentcoordinatesare,youcanusethiscommand.G92alonesetsallthreeaxestozero.Itcanbeappendedwithanumbertosetanaxisatthatcoordinatewithoutchangingtheothers;
forexample,“X52.3”wouldsettheXaxisto52.3withoutchangingtheotheraxes.Anycombinationcanbeusedtospecifyindividualaxes.
M92(settingsteps):Ifyouneedtochangehowmanystepsareneededpermillimeterofmovement—suchaswhenyou’recalibratingyourprinter—youcandosowiththiscommand.Forexample,“M92Y200”
wouldsetthestepspermillimeterto200ontheYaxis.
M119(endstopstatus):Thistellsyouifeachoftheendstopsiscurrentlyreadinghighorlow,whichshouldletyouknowifthey’retriggeredornot.Youcantrypushinganendstopswitchwithyourfingerwhenyourunthecommandtotestiftheendstopisworking(thestate
shouldchange).
M500(storingEEPROMvalues):IfyouhavemodifiedanyoftheEEPROMvalues(likestepspermm)usingG-codecommands,thiscommandstoresthempermanentlyintheEEPROM.Becarefulwiththis,asit’seasytoaccidentallyoverwriteyoursettingswithunusablevalues.
M503(readingEEPROM
values):ThiscommanddisplaysallofthevaluescurrentlystoredintheEEPROM.Thecommandnameatthebeginningofeachreturnedvaluecanalsobeusedtochangetheparticularvaluesonthatline.Soifareturnedlinereads“M92X200.0Y200.0Z802.2,”youcanchangeanyofthosevaluesbyenteringsomethinglike“M92Z820.3”
WhileyoumaynoteverhavetoactuallysendanymanualG-codecommands,it’sagoodideatobecomeatleastvaguelyfamiliarwiththeseincaseyoueverneedthem.
WATCH OUT!If you were so inclined,
you could technically printan entire part by manuallysending G-code commandsto the 3D printer. Of course,doing so would be hugelyimpractical, and there reallywouldn’t be any point indoing so.
The Least You
Need to KnowFirmwareisbase-levelsoftwarethatrunsonthecontrolboardandisstoredinROM.It’swrittenspecificallyforaparticularcontrolboardandhardwaresetup.
Hostsoftwareiswhatallowsyourcomputertoconnecttoyour3Dprinter.Italsosendscommandstorunprints.
Slicingsoftwaregenerates
theG-codeinstructionsthataresenttothe3Dprinterbythehostsoftware.It’softencombinedintoasinglepackagewiththehostsoftware.
G-codeistheprogramminglanguageusedtoissuecommandstomost3Dprinters.Thisiswhattheslicingsoftwaregeneratestoprintparts,butyoucanalsoenterG-codecommandsmanuallytoperformsomeusefulfunctions.
CHAPTER
12
Leveling theBed and
Adjustingthe Z Height
In This Chapter
Whyyourbedneedstobelevel
Manuallylevelingorauto-levelingyourbed
HowtosetyourZheight
You’vealreadylearnedhowimportantitisforthefirstlayerofaprinttostickwelltothebed.Thematerialthebuildplatformismadefrom
isimportant,asarethesurfacetreatmentsyouapplytoit.Butthefilamentwillneverstickwelltothebedifit’snotlevelorifyourZheightisn’tsetproperly.
TheZheightishowfarthenozzleisfromtheprintbed.It’simportant,becauseitdetermineshowmuchthefilamentispushedontothebedasitisextruded.Thebedbeinglevelisequally
important,becauseotherwisetheZheightwillchangedependingonwhatareaofthebedthenozzleisover.Inthischapter,IgooverhowtogetthebedandZheightwhereyouneedthemtobe.
Why Does
Your BedNeed to BeLeveled?WhenIsaythebedneedstobelevel,Idon’tmeanitneedstobelevelrelativetoEarth;youdon’tevenwanttotouchabubblelevelforthis.Instead,thebedneedstobelevelrelativetotheaxesof
the3Dprinter.Basically,theZaxisneedstobeperpendiculartothebuildplatform,andtheXandYaxesneedtobeperfectlyparalleltothebuildplatform.
Whydoesitmatter?Alevelbedensuresthenozzleisalwaysaconsistentheightabovethebed.Thefirstlayerofaprintisverysensitivetohowfarthenozzleisfromthebed.Toohigh,andthe
filamentwon’tstickwell;toolow,andthenozzlewilldragthroughthefilament.
Theacceptableheightisaverysmallwindow(usuallyonlyonetenthofamillimeterorso).Soevenifthebedisonlyslightlyofflevel,itcouldeasilymakepartsofthebedtoohighortoolow.
Forexample,imagineyouhada150mm-widebedandhadyourZheightsetat
.25mmatoneend.Ifthebedwerejust1°offfromlevel,theZheightattheotherendofthebedwouldbemorethan2.8mm.Thatcouldeasilycauseyourprinttofail,becausethefilamentwouldn’tadherewellatthefarend.
Evenatjust1°fromlevel,theprint
wouldberuined.
Thismakeslevelingvirtuallyanecessityinordertoprintsuccessfully.Itshouldbethefirstthingyoudowhenyoufirstsetupa3Dprinter,andthenfairlyfrequentlytomakesurethebedstayslevel.Therearetwowaystolevelaprintbed:manuallevelingandauto-leveling.
Manual Leveling
Mostconsumer3Dprintersoutrightnowrequirethatyoumanuallyleveltheprintbed.It’svirtuallyimpossibletomanufactureaprinterwithaperfectlylevelbedthatstayslevel,somostmanufacturersincludesomesortoflevelingmechanisminthedesign.
Thebuildplatformisgenerallyattachedtothreeorfourscrewswithsprings,andyoutightenorloosenthe
screwsinordertoadjusttheheightofthebedateachpoint.Othermechanismsareusedinsomeprinters,butallofthemhavetoprovidesomewayofadjustingtheheightinatleastthreeplacesinordertokeepthebedlevelrelativetoboththeXaxisandtheYaxis.
HOT TIPLeveling a build
platform also requires it tobe completely flat. If the bedis warped or bent at all, it willbe impossible to level. Therewill always be part of thebed that isn’t completelyparallel to the X and Y axes.This is why glass andborosilicate are socommonly used for buildplatforms; those materialsare easy to make and keepflat. Other materials, likealuminum, are still used forbuild platforms but canpretty easily become
warped. Still, even with aperfectly flat build platform,the bed still has to beleveled.
Tolevelthebed,allyou’llneedisapieceofpaper.Theideahereisthatyou’llsetyourZheightatonecornersothenozzlejustbarelytouchesthebed.Youthenplacethepieceofpaperbetweenthenozzleandbedandpullitout.
Payattentiontohowmuchforceittakestopullthepaperoutandhowmuchresistancethereis.
Manuallylevelingthebuildplatformbyusingapieceofpaper
tomeasureresistance.
Forthefirstcorner,you’lljustwantasmallamountofresistancethatcanbe
overcomeeasilywithalittleforce(withouttearingthepaper).Youthenraisethenozzleandmoveitontotoanothercorner(preferablytheonediagonallyacrossthebed)andloweritonthepaperthere.Pullthepaperoutandpayattentiontohowmuchresistanceittakes.Iftakesmoreresistancetopullthepaperoutonthesecondpointthanitdidonthefirst,you’llneedtolowerthatcornera
bit.Ifittakeslessresistance,you’llneedtoraisethatcorner.Fine-tuneituntilittakesapproximatelythesameamountofresistanceasthefirstcorner.
Next,repeattheprocessforthethirdandfourthcorners.Theresistanceittakestopullthepaperoutshouldbeequalbetweenallfourcorners.Onceallfourcornershaveequalresistance,thebedwill
belevel.
Onethingyoushouldkeepinmindisthatthisprocessisn’tquiteassimpleasitseemsintheory.Ittakessometimetodoandcanbefairlyfrustrating.Itmighttakeyouafewtriestogetasenseforhowmuchresistanceyouneedtofeelinthepaper,andonceyoustartprinting,youmaynoticethatfilamentadheresbetterinsomeplaces
thanothers.Ifthat’sthecase,youcanjustmakesomefineadjustments,likeaquarterturnofthescrews.
Auto-LevelingAsyoucanimagine,manuallylevelingtheprintbedisn’texactlyafunprocess.Itcanbetimeconsumingandfrustrating.Forthatreason,many3D
printermanufacturershavereleasedprintersthatincludeauto-leveling.
Theauto-levelingprobeonaPrintrbotSimple.
Sohowdoesauto-levelingwork?Itdoesn’tphysically
adjustthebedatall.Infact,auto-levelingsystemsdon’thaveanymovingpartsatall.Instead,theyworkcompletelyinthefirmwareofthe3Dprinter.
Auto-levelingsystemsessentiallyworkbyvirtuallylevelingthebed.Theydothisbyraisingandloweringthenozzledependingonwhatpointofthebedit’sat.Theydothistokeepthenozzleata
consistentheightabovethebed,nomatterwhatpointit’sat.
Forthissystemtowork,theprinter’sfirmwarehastoknowhowmuchtoraiseorlowerthenozzledependingonwhereitisatintheXandYdirections.Thisisdonewitheitheraphysicalprobe(basicallyjustaswitch),aninductiveprobe(whichistriggeredwhenitsenses
metal),oranopticalprobe(whichistriggeredwhenitgetscloseenoughtoseethebed).Thefirmwarecontrolstheprocessandmovestheprobetothreecornersofthebedtomeasuretheirheightsrelativetoeachother.
FASCINATING FACTThe probes used in
auto-leveling systems caneither be triggered byphysical contact or bysensing the bed withouttouching it. In this way, theprobes work similarly to endstop switches.
Oncethefirmwarehastheheightinformationforeachofthethreecorners,itcanuse
thatinformationtodeterminehowfarofflevelthebedis.Itbasicallyconstructsaflatplanefromthethreepoints,whichrepresentstheactualbed.Itthenknowshowfartomovethenozzleupanddownatdifferentpointsonthebed.
Forexample,ifonecorneris1mmlowerthananothercorner,theprinterknowstolowerthenozzleby1mmwhenit’satthatcorner.Of
course,itdoesn’tjustsuddenlylowerorraisethenozzlewhenitreachesacorner.Itwillmovethenozzleupordowngraduallyasitapproacheseachcornerasnecessarytokeepthenozzleataconstantdistancefromthebed.
Thismakesauto-levelingaveryconvenientfeature;however,itdoeshaveacoupleofdrawbacks.The
firstisthatitreliesontheaccuracyoftheprobe,whichmaynotalwaysbeperfect.Thesecondisthatithasnowaytocompensateforwarpedbeds.Forinstance,ifonecornerofthebedwaswarped,youcouldstillmanuallylevelthebedandjustavoidprintinginthatcorner,whichcan’thappenwhenyouuseauto-leveling.
However,thosearerelatively
minordrawbacks.Formostpeople,theconvenienceofauto-levelingfaroutweighsthepotentialproblems.Andforthatreason,auto-levelingisrapidlybecomingmorepopularandcommon.
How toAdjust Your
Z HeightOnceyourbedhasbeenleveled,youcanworkonsettingyourZheight.TheZheightishowfarthetipofthenozzleisfromthesurfaceoftheprintbed.Thiswillbejustafractionofamillimeterandneedstobesetveryprecisely.
Unfortunately,settingitisn’tjustamatterofwhippingoutarulerandmeasuringa
specificdistance.Thenecessarygapbetweenthenozzleandthebedcanvarydramaticallydependingonanumberoffactors,suchasthefollowing:
Filamentsize
Nozzlesize
Layerheight
Otherprintsettings
Allofthosefactorshaveone
result:howmuchplasticisbeingsqueezedoutofthenozzle.That,inturn,determineshowmuchofagapneedstobebetweenthenozzleandthebed.Technically,youcouldprobablycalculatewhattheidealheightis.Butevenifyoudidcalculateit,itwouldbedifficulttomanuallysetittothatheight.
Sohowdopeoplegoabout
actuallysettingtheZheightthen?It’smostlyamatteroftrialanderrorthatgoeslikethis:
Setthenozzleclosetothebedwithjustatinygap,andstartprinting.
Ifthefilamentdoesn’tstick,lowerthenozzle.
Ifthefilamentisgettingsmashedintothebedbythenozzle,raisethenozzle.
Youcangobackandforthlikethisafewtimesuntilyougetitright.
Setting the ZHeight Manually orAutomaticallyOnmost3Dprinters,you’llbesettingtheZheightmanually.Thereissomesortofscrewmechanismtoraise
orlowertheZstop(wheretheendstopswitchmakescontact),soyoujustmakesmalladjustmentswiththescrewtochangetheZheight.
However,onprinterswithauto-leveling,theprobeusuallyactsasyourendstopswitch.Inthatcase,eithertheprobeitselfisphysicallyadjustedtochangetheZheight,orit’sdoneinsoftware.Ifit’sdonein
software,theideaistospecifyhowmuchthenozzleneedstoberaisedbackupaftertheprobeistriggered.
Bothsystemsworkwell,thoughmanualadjustmentsusuallytendtobequicker.That’sbecauseyoudon’thavetofiddlewithanysettingsinthefirmware—allyouhavetodoismakeaquickturnontheadjustmentscrew.
Knowing the“Correct” Z HeightKnowingwhatthe“correct”Zheightistakesalittleexperience.AsIsaid,you’relookingforhowtheextrudedfilamentstickstothebed.Ifit’sjustbarelyclingingon(orworse,doesn’tstickatall),it’sobviouslytoohigh.Thiswillusuallylooklikeathreadjustlyingonthebed.When
theZheightistoohigh,it’sobviouswhythereisgoingtobeaproblem:thefilamentjustwon’tstickwell.
Noticingwhenit’stoolowisabitmoredifficultthough.Inthatcase,itwilllooklikeaflatline,almostlikeit’sbeingdrawnontothebed.Unfortunately,thereasonthisisaproblemisn’talwaysaproblemuntillater.
HOT TIPAlways pay close
attention to your first layer.It’s the most important partof the print, and is vital to thesuccess of the print. Even ifyou’ve leveled your bed andset your Z height properly,it’s possible that it couldneed to be recalibrated (it’snormal for 3D printers toneed recalibrationoccasionally). Watching thefirst layer is the best way tomake sure it’s correctly
adjusted.
Whathappensisthatthefilamentstillhastogosomewhere,soittendstoexpandout.Aseachnewlineoffilamentisaddednexttothepreviousone,wavesstarttodevelopinthelinesfromthenozzledraggingthroughit.Eventually,thisaddsupandthenozzlewillbe
bouncingallovertheplaceonthesewaves,ruiningyouraccuracyinthefirstfewlayers.
Thefirstfilamentlinesonthefirstlayershouldadherewellwithoutbesquishedbythenozzle.Asyoucanseewiththislayer,thenozzlewastoolowandsquishedthefilamentonthecorner.
Sowhatshoulditlooklike?
Youwantanicethree-dimensionalshape,butnotsomuchsothatit’sjustathreadoffilamentlyingonthebed.Ifthefilamentnaturallycomesoutinacircularcross-section,you’relookingforittohaveasortofsquishedovalcross-sectiononthebed.
LearningwhattheperfectZheightlookslikewilltakesomeexperience.You’llneedtoseetheeffectsofitbeing
toohighandbeingtoolow.Luckily,itdoesn’ttakelongtogetitright.Itshouldalsobeapparentprettysoonintheprintingprocessifit’snotright.
Intheend,levelingthebedandsettingtheZheightareallaboutgettingthatfirstlayerright.Ifyougetthatfirstlayerright,youcanusuallycountontheprintturningoutwell.
The Least YouNeed to Know
It’simperativethatthebedbelevelinordertosuccessfullyprintapart.
Manuallylevelingthebedisn’tafunprocess,butitcanbedonewithjustapieceof
paper.
Manymanufacturersarenowincludingauto-levelingsystems,whicharemoreconvenientthanmanualleveling.Theytelltheprintertoeitherraiseorlowerthenozzlebasedonreadingsfromaprobe.
ProperlysettingyourZheightisasimportantaslevelingthebed.Itneedstobesetsothefilamentadhereswellwithoutbeingsmashedbythenozzle.
CHAPTER
13
Slicing andPrinting
In This Chapter
Explanationsofallofthe
slicersettingsHowtoprepareyourobjectforprinting
Howtogetaprintstarted
Soyou’vegotyourprinterallunpackedandsetup.YourbedisleveledandyourZheightissetup.Youknowpracticallyeverythingthereistoknowaboutthehistoryof3Dprintingandhowdifferentkindsof3Dprinterswork.
Nowit’stimetoactuallystartprinting!
Todothat,youneedtogetyourslicingsoftwareconfigured.Youalsoneedtolearnabouthowtosetupanewprintandhowtorunit.Inthischapter,Igooverboththesethings.Don’tworry,you’reinthehomestretch.Soonyou’llbein3Dprintingbliss!
ConfiguringYour SlicingSoftwareIfyou’vefollowedChapter11,youhavealreadysetupyourhostsoftware,andmostlikelythehostsoftwarehadslicingsoftwarebundledwithit.(Ifyoutookmyrecommendation,you’re
usingSlic3r,whichisbundledwithRepetier.)Youhavealsoentered3Dprinter-specificsettingsinthehostsoftware.However,youstillneedtodothesameforyourslicingsoftware.
Why?Becausethey’restillseparatepiecesofsoftware,eveniftheywerebundledtogether.Technically,bothpiecesofsoftwarecanbeusedindependentlyofeach
other.Soeachhasitsownsettingsandneedstobeconfiguredindividually.
TheSlic3rconfigurationcanbefoundwithintheRepetiersoftware.
Ifyou’reusingRepetier,configuringSlic3risprettyeasy.FromtheSlicertabin
Repetier,youcanjustclicktheConfigurationbuttontobegin.Ifyou’reusinganothersoftwarecombination,youcanfindsimilarsettingswithintheparticularslicingsoftwareyou’reusing.
However,youshouldn’tlamentifyou’reusingsomethingotherthanSlic3r.It’sallprettymuchthesame,andsimilarsettingswillbefoundinallslicingsoftware
(maybewithaslightlydifferentname).Forthatreason,I’mnowgoingtocoverwhateachoftheslicersettingsactuallydoes.Onceyouunderstandwhatthesettingsactuallydo,you’llhavenotroubleusingthemregardlessofwhatthey’recalled.
Slicer
SettingsExplainedIngeneral,theslicingsettingsyou’llbeconfiguringcanberoughlydividedintothreedifferenttypes:printersettings,filamentsettings,andprintsettings.IntheSlic3rconfigurationwindow,thesearehelpfullydividedupintothreeseparatetabsfor
yourconvenience.
ThesettingsintheSlic3rconfigurationwindowaredividedintothreetypes:printsettings,filamentsettings,andprinter
settings.Thisshowsthedifferenttabsfortheminthewindow.
Inotherslicingsoftware,they
mightbedividedupdifferently(ornotdividedupatall).Still,it’sagoodideatothinkofthemasseparatekindsofsettings.Thiswillhelpyoumentallyorganizethemintothosesettingsyou’llneedtotweakfrequently,occasionally,orrarely.
HOT TIPMost software will
allow you to save multipleconfigurations. This lets youquickly switch betweenpredefined settings that youset up for specific types ofprints, specific filaments,and even for multiple 3Dprinters. I advise you to takeadvantage of multipleconfigurations, so you canreuse settings withoutconstantly tweaking them.
Printer SettingsTheprintersettingsarethesettingsyoushouldrarelyhavetomodify.Ideally,you’lljustsetthemuponceandthennevertouchthemagain—oratleastnotuntilyougetanew3Dprinter.Thesetelltheslicingsoftwarealittlebitabouttheprinteritself,soitknowswhatit’sworkingwith.
Theprintersettings,whichyou’llrarelychange,givetheslicingsoftwareinfoabouttheprinter.
Printersettingsarethefirstthingyoushouldconfigure.Luckily,thereisn’tawhole
lottosetuphere.Thefollowingarethesettingsyou’llencounter(keepinmindthatthesemaybeinseparatesectionsofthePrinterSettingstab):
Bedsize:Thisisaneasyonetostartwith!AllyouhavetodoisenterthesizeofyourprintbedintheXandYdirections.
Printcenter:Asyoumightexpect,thisisjusttheXand
Ycoordinatesforthecenterofthebed.Generally,youjustdividethebedsizeby2andenterthosenumbershere.Butyoucanmodifythisifyouwantittocenteryourprintsinanotherspot.
G-codeflavor:Hereyou’llspecifywhatkindofG-codeyourprinteruses.Thismightbeahead-scratcheratfirst,butdifferentcontrolboardscanactuallyinterpretG-code
slightlydifferently.Ifyoudon’tseeyourspecificprinterorcontrolboardlisted,it’susuallysafetouse“RepRap.”
UserelativeEdistances:YoucancheckthisboxifyouwanttouserelativeG-codedistances(asopposedtoabsolutecoordinates).Unlessyourmanufacturersaysyouneedtocheckthis,justleaveitunchecked.
Extruders:Thenumberof
extrudersyour3Dprinterhascanbeenteredhere.Normallyit’llbejust1,butifyouhavemultipleextruders,youcanspecifythathere.Ifyoudo,itwilladdsectionstosetuptheadditionalextruders.
Usefirmwareretraction:Thisletsyourfirmwarehandletheretractionsettings(asopposedtohavingyourslicingsoftwaredoitmanually).Inmostcases,
you’llwanttoleavethisoffunlessyouhaveareasonnotto.However,ifthesoftwareretractionsettingsdon’tworkproperly,youcanusethefirmwaresettings.
Vibrationlimit:Youcanattempttoreduceprintervibrationproblemswiththissetting.However,it’sdifficulttogetittoworkright,andthevibrationsusuallyaren’tsubstantial.Irecommendyou
leavethisat0todisableit.
StartG-code:WhateveryouenterherewillbeaddedtothebeginningofeveryG-codefilethesliceroutputs.SotheseG-codefunctionswillbeperformedatthebeginningofeveryprint.Usually,peopleusethisforthingslikehomingalltheaxes(G28)orauto-leveling(G29).
EndG-code:Thisworkslike
thestartingG-code,exceptitgoesattheend(crazy,huh?).Thisismostoftenusedtoturnoffeverythingontheprinter,soitdoesn’tstayhotwhenyou’reaway.Fornow,youcanjustleavethedefaultcommandsthere.
LayerchangeG-code:ThisalsoaddsG-code,exceptitputstheG-codeinbetweeneverylayer.Youcanaddcodeherethatyouwanttobe
executedeverytimethelayerchanges(forinstance,youcouldaddapausetoletthepreviouslayercoolbeforestartinganewone).
ToolchangeG-code:G-codeenteredherewillbeinsertedanytimetheprinterswitchesfromusingoneextrudertousinganother.Youcancompletelyignorethisifyouonlyhaveoneextruder.
Nozzlediameter:Thisis
whereyouneedtoenterthephysicaldiameterofthenozzleopeningonyourhotend.Ifyoudon’tknowit,don’tjustguess!Thisisanimportantsetting,solookupyournozzlediameterifyou’renotsure.
Position:Ifyouhavemorethanoneextruder,thissettingspecifieshowfarapartthetwonozzlesoftheextrudersare.
Retractionlength:Retractionreversestheextrudertopullthefilamentbackoutofthehotendslightly.Thisimprovesprintqualitybyreducingblobswhenlinesegmentsarecompleted.Forthis,1mmor2mmisusuallyagoodsettingtotry.
LiftZ:Thisactuallyliftsthenozzleup(bythespecifiedamount)whenalinesegment
isfinishedandtheprinterismovingtoanotherposition.Thiscanhelpkeepthenozzlefromdraggingacrossyourprint.
Speed:Thisisjustthespeedtheextruderwillretractfilament.Whateverthedefaultisshouldworkfine(usually20to40mm/s).
Extralengthonrestart:Ifyou’rehavingproblemswithfilamentnotextruding
immediatelyafteraretraction,youcanusethissettingtoextrudealittleextra.However,youwillhavetoexperimentwiththelengthtouse.
Minimumtravelafterretraction:Youcanusethissettingtoskipretractionsonmovesthatonlycoverashortdistance.Thatdistancecanbeadjustedtoyourliking.
Retractonlayerchange:
Thisforcesaretractionwhenyoumoveuptothenextlayerofaprint.
Wipewhileretracting:Tofurtherreduceblobsandstringing,youcanusethissettingtophysicallywipethenozzleontheprintbetweenmoves.Personally,Irecommendthatyouturnthisoff,becauseithasatendencytomessupthesurfaceasitwipes(asyoumightexpect
fromdraggingthehotnozzleontheplastic).
Filament SettingsThesearesettingsyoushouldn’thavetomodifyoftenbutthatyouwillhavetoadjustoccasionally.Basically,they’resettingsthatdefinethespecificationsofyourparticularfilamentandhowitshouldbeusedby
theprinter.
Thefilamentsettingsarethereforyoutoenterthespecificationsof
thefilamentyou’reusing.
You’llusuallyneedtomodifythesewheneveryouputanewrolloffilamenton(atleast
slightly).Thisisbecauseeverymaterial,manufacturer,color,andevenspecificrollisslightlydifferent.Thediameterofthefilament,idealextrusiontemperature,bedtemperature,andcoolingsettingswillallvary.
Thefollowingarethedifferentfilamentsettingsyou’lldealwith:
Diameter:Thissettingiseasilyoneofthebiggest
causesofprintqualityproblems.Whileyoucanjustsetitto1.75mmor3.00mm,theactualfilamentisrarelyactuallythatsize.Instead,foreveryrolloffilamentyouget,youshouldmeasurethediameterinafewplaceswithcalipersandentertheaveragemeasurementhere.Thisensuresthattheslicingsoftwareaccuratelycalculateshowmuchfilamenttoextrude.
DEFINITIONCalipers are a
common measurement toolused in a wide range offields and industries. Theycome in both analog anddigital varieties and are usedto measure lengths,distances, and depths.Calipers are capable of veryhigh precision andcommonly come in 6- to 12-inch sizes (though largerand smaller ones exist).
Extrusionmultiplier:Youcanusethissettingtofine-tunehowmuchfilamentisbeingextruded.Forexample,ifyounoticetheprinterisoverextruding,youcansetitto.95soitonlyextrudes95percentofwhatitnormallycalculatesisnecessary.
Firstlayerextrudertemperature:Thisiswhereyousetthetemperatureforthefilamentyou’reusing.
Thefirstlayercanbesetindependentlybecausesomepeopleliketomakethefirstlayerhotterinorderforittostickbetter.
Otherlayersextrudertemperature:Thisisthefilamentextrusiontemperaturefortherestofthelayers(afterthefirstone).
Firstlayerbedtemperature:Ifyouhaveaheatedbed,youcansetits
temperatureforthefirstlayerhere.
Otherlayersbedtemperature:Thisiswhereyousetthebedtemperaturefortherestofthelayers.
Keepfanalwayson:Ifyouhaveaprintfanyouwanttorunallthetime,checkthis.However,Irecommendyoudon’tdosoforABS,asitcauseswarpingproblems.
Enableautocooling:Thisletstheslicingsoftwaredecidewhentoturnthefanon,dependingonwhatyouspecifyintheothersettings.
Fanspeed:Thisistheminimumandmaximumfanspeedusedatanytimeduringtheprint.Differentfansrespondtothisdifferently(forexample,somewon’teventurnonatallbelowacertainnumber).Pay
attentiontohowyourfanactsandsounds,andfine-tuneitwiththesesettings.
Bridgesfanspeed:Bridgesarepartsoftheprintwherethefilamenthastobeextrudedacrossanemptyspacewithnoothermaterialbelowit.Tokeepthesefromdrooping,it’srecommendedthatyoucoolitquicklywithafan.Soifyouhaveafan,enteranumbertoturnthisup.
Disablefanforthefirst:AsImentionedpreviously,somepeopleliketheirfirstlayertobehottohelpitstick.Withthissetting,youcanturnoffthefanforaspecifiednumberoflayersinthebeginningtohelpwithadhesion.
Enablefaniflayerprinttimeisbelow:Ifaparticularlayeroftheprintisverysmall,theremaynotbeadequatetimeforittocool
beforethenextlayerisadded.Youcanusethissettingtoforcethefantocomeontocoolthosesmalllayers.
Slowdowniflayerprinttimeisbelow:Inextremecases(verysmalllayers),thefanisn’tenoughtocoolthelayerbeforethenextisadded.Thiscancausethelayerstosortofmeltanddeform.Thissettingforcestheprintertoslowdownontheselayersto
givethemtimetocool.
Minprintspeed:Thisisslowesttheprinterisallowedtomoveonthosesmalllayers.Settingthistoolowcanmakesmallpartstakeaverylongtimetoprint.
Print SettingsSoyou’reatthefinaltaboftheslicersettings.Doyouwantthegoodnewsorbad
newsfirst?Let’sstartwiththebadnews:thistabhasthemostsettingsbyfar.Thegoodnewsisthatalotofthesesettingsareforadvancedusage.Forthetimebeing,it’sbesttojustleavethoseatthedefaultsorautomaticsetting.
HOT TIPA lot of the print
settings are for really fine-tuning specific areas of theprint, meaning they’re reallyfor advanced users. So ifyou don’t see a setting listedin this chapter, don’t fret!Just leave it at the default orautomatic setting and moveon. You can always look upthe specific setting if you’rereally curious about it.
ThePrintSettingstabcanbeascaryplace,butmanyofthe
settingscan(andshould)beleftontheirdefaults.
Thefollowingarethevariousprintsettingsyou’ll
encounter:Layerheight:Ifyoupurchasedyourprinter,themanufacturerprobablygaveyouarecommendationforthissetting.Ifnot,youcansafelysetthistoabout65to75percentofyournozzlediameter.
Firstlayerheight:Often,it’sgoodtomakeyourfirstlayerbiggertoimproveadhesion.Agoodnumbertostartwith
is125percent.
Perimeters(minimum):Inordertogivethewallsofthepartanice,solidstructure,youneedtospecifyaminimumnumberofsolidperimeters.Twotofouraregoodstartingpoints.
Spiralvase:Thisniftyfeatureallowstheentireparttobecreatedfromonecontinuouslayerthatslowlyrises.However,itreallyonly
workswithasingleperimeterandnoinfill.Soyoushouldonlyusethisfortall,hollowobjects(likeavase),meaningyoushouldnormallyleavethisblackorunchecked.
Solidlayers(top):Thisishowmanysolid(noninfill)layersareonthetop.It’ssimilartoperimeters,justforhorizontalwalls.Again,2to4shouldworkwell.
Solidlayers(bottom):This
issamethingastheprevioussetting,justforthebottomlayers.
Filldensity:Infillisusedontheinterioroftheparttoavoidhavingtomakeitsolid.Thisreducesweight,filamentusage,andwarping.Forpartsthatneedtobestrong,use50to80percent.Forpartsthatdon’tneedtobestrong,use20to50percent.
Fillpattern:Thisindicates
whatkindofpatternwillbeusedfortheinfill.Honeycombandrectilinearnormallyworkthebest(withrectilinearusuallythefastest).
Top/bottomfillpattern:Ifyouwantadifferentpatternforthetopandbottomlayers,youcanspecifyithere.However,I’drecommendstickingwithrectilinear.
Speedsettings:Unfortunately,Ican’tmake
recommendationsforthesesettings,asthey’reveryhighlydependentonyourspecificprinter.Startwiththemanufacturer’srecommendationsorwiththedefaults.
Skirtloops:Inordertogettheextruderflowingwellbeforeyouactuallystartprintingthepart,youcanhaveitprintacoupleofloopsaroundthepart.Thishasthe
dualpurposeofallowingyoutomakesureit’scompletelyontheprintbed.Youcanjustenterthenumberofloopsyouwanttheprintertomakebeforeitstartsprintingtheactualpart.
Distancefromobject:Thisishowfartheloopswillbeprintedfromtheedgesofthepart.Thisneedstobefartherthanthebrim(ifyouuseit),whichI’llgooverina
moment.Ifthepartisverylargeandbarelyfitsonthebed,youmayneedtoreducethistomaketheoverallprintsmaller.
Skirtheight:Youcanusethistomaketheskirtverytalltobuildasortofwallaroundyourpart.Thiscanhelpreducedraftsonthepartinordertoavoidwarping.
Minimumextrusionlength:Youcansetthisifyouwant
tomakesuretheskirtusesacertainamountoffilament.Usually,youcanjustleavethisat0unlessyouhaveextrusionissues(suchasunderextrusioninthebeginning).
Brimwidth:Abrimisasortofbasethat’sprintedaroundyourpart.Thiscanbeusefulformakingsurethebaseofthepartstaysstucktothebedandforkeepingtall,thinparts
upright.Youcanspecifythewidthofthebrimaroundthepart,andthebrimcaneasilyberemovedaftertheprintisfinished.
Supportsettings:Iftheparthasoverhangsandwillrequiresupports,youcanturnonthesupportgenerationhere.However,Irecommendusingthedefaultand/orautomaticsettingsforthebestresults.
Raft:Araftservesasimilarpurposetothebrim,exceptit’sprintedunderneaththepart.Youcanspecifythethicknessoftheraft,aswellastheinterfacinglayerswiththepart.
Multipleextruders:Ifyou’reusingmultipleextruders,thissectionisforyou.Essentially,itallowsyoutospecifywhichextrudersareusedfordifferentoperations.
Forexample,youcoulduseoneextruderforsupportsandtheotherfortheactualpart.
HOT TIPWhen setting up
multiple extruders, thesettings that tend to be themost confusing are theoffset settings. These areimportant, because they tellthe slicing software wherethe second extruder is inrelation to the first extruder.
The nozzles of the twoextruders must be at thesame height, so this willspecify how far the center ofthe second nozzle is fromthe first (in both the X and Ydirections). If these are evena little off, the filamentextruded by the secondextruder will be deposited inthe wrong place.
Preparing forand Runninga PrintAfteryou’veputinyourfilament,printer,andprintsettings,it’stimetogetdowntopreparingforandrunningaprint.Thisiswhereyou’llspendmostofyourtimewhenyou’reprintingthings.
Becauseyou’llfrequentlybemodifyingyourprintsettingsforspecifickindsofparts,you’llalwaysneedtodothepreparationandrunningstepstomakesureyourpartcomesoutcorrectly.
Host PreparationPreparingyourprintisaprettysimplebutimportantprocess.I’llgoovereach
specificstepinmoredetailintheprojectsectionsofthisbook,butletmecoverthegeneralideahere.
Irecommendthatyoubeginbyconnectingtoyourprinterandheatingupthehotendandheatedbed(ifyouhaveone).Thiswillgiveittimetowarmupwhileyou’redoingtherestofthesteps.Youcanthenloadthepartorpartsyouwanttoprint.
Withthepartsloaded,you’llbeabletoviewthemintheObjectPlacementtabinRepetier.Here,youcanmovethemaround,rotatethem,duplicatethem,deletethem,andsoon.Youshouldalsotakeamomenttomakesureeverythingfitsonthebedandthatthey’reallorientedproperly.(Tryingtoprintapartupsidedownwillusuallyresultinfailure.)
Ifeverythinglooksgood,youcanmoveovertotheSlicertab.Ifyou’reinRepetierandusingSlic3r,makesureSlic3risselectedundertheSlicerdrop-downbox.Belowthat,you’llnoticedrop-downmenusforyourPrintSetting,PrinterSetting,andFilamentSettingconfigurations.Makesuretheonesyou’reintendingtouseareselected.Onceyou’veverifiedthose,youcanclicktheSlicewith
Slic3rbutton.
Afterloadingyourpart(s),makesuretheyfitonyourbedandareorientedproperly.Asyoucansee,thismodelofanelephantfitsonthebedandisrightsideup.
Running a Print
Slicingyourobjectorobjectscantakeanywherefromafewsecondstohoursdependingonthecomplexityofthepart,howpowerfulyourcomputeris,andthesettingsyouchose(forexample,supportstakemoretimetoprocess).Butonceit’sfinishedslicing,youshouldbepresentedwithapreviewoftheprint.
Lookoverthepreview,whichshowsyouwheretheslicing
softwareisintendingfortheprintertoactuallyextrudeplastic.Itshouldlooklikeyouroriginalpartbutbrokendownintolines.Ifyou’reusingsupports,thosewillbeshownaswell.Thisisyourchancetocatchanyserioussettingproblemsthatmightcausetheprintertodounexpectedthings.
Thepreviewshowstheparttobeprintedbrokendownintolines.
Ifeverythinglooksgood,youcangoaheadandpushStartPrinttostartprintingthepart.Yourprintermustremainconnectedtotheprinter
throughouttheentireprocess(anditmustbeturnedon,ofcourse).Itmighttakeyourprinteraminuteortwotostartmovingifitstillneedstoreachtherequiredtemperature.
Onceitstartsprinting,don’tgorunningoffquiteyet.Stickaroundforafewminuteswhileitprintsthefirstlayer.Yourfirstlayerisbyfarthemostimportantone,because
it’sthefoundationfortheentirepart.Makesureitstickswelltothebedandthatthefilamentisextrudingwell.Then,inanywherefromafewminutestoadayortwo,yourpartwillbedone!
The Least YouNeed to Know
Mostofthefilament,printer,andprintsettingsare
important,sotakethetimetolearnwhattheydo.Butwhenindoubt,stickwiththedefaults.
Makesureyourobjectsareplacedandorientedcorrectlyandthattheyfitonthebedbeforeslicing.
Alwaystakeaquicklookatthepreviewtomakesureeverythinglooksrightbeforestartingaprint.
Thefirstlayerofaprintisalwaysthemostimportant
one.It’swellworthyourtimetostickaroundforafewminutestomakesurethatfirstlayergoeswell.
CHAPTER
14
TroubleshootingYour Prints
In This Chapter
Howtoidentifyprint
problemsExtrusion,temperature,andadhesionissues
Fixingothercommonprintqualityissues
3Dprintingisprettycomplicated,andthatmeanstherearealotofproblemsyoucanruninto.Afewsmalltweaksinyoursettingscaneasilymakethedifferencebetweenahigh-qualityprintandonethat’sgoingtoget
thrownaway.Butbecausetherearesomanyfactors,itcanbedifficulttofigureoutwhattheproblemis.Inthischapter,Iwalkyouthroughsomecommonissuesandwhatyoucandotofixthem.
What’s theProblem?
Obviously,thereareawholelotofthingsthatcangowronginthecourseofyour3Dprintingjourney.Ifyou’refamiliarwithMurphy’sLaw,youknowthatanythingthatcangowrongwill.Theseproblemscanbeasminoraspoorsurfacequality(likeripples)tomajorproblemsthatcauseyourentireprinttofail.
FASCINATING FACTYou can hold on to your
failed prints for use in thefuture. They can be used tomake ABS glue and evenyour own filament. If you domake your own filament,however, keep in mind thatyou shouldn’t use more than10 percent recycled plastic.If you don’t have the abilityto make filament yourself,you can drop the used ABSoff at your local hackerspaceor makerspace for them to
use.
Mostpeoplewillspendagreatdealoftimefine-tuningtheirsettingstogetreallyhigh-qualityprints.Butwhatifyourpartsarecomingoutterribly?Itcanbeveryfrustratingifthisishappeningandyoucan’tevenachievemediocreresults.
Completefailuresofprintslikethisarenotuncommon.
Luckily,theseissuescanusuallybeidentifiedfairlyeasilybycomparingyourbadprinttoknownproblems.
Onceyou’vefiguredoutwhattheprimarycauseoftheproblemis,youcanadjustyoursettingstofixit.Actuallygettingthesettingsrightmighttakealittletrialanderror,butatleastyou’llknowwheretofocusyourattention.
Extrusion
ProblemsExtrusionproblemsarethosecausedbyimproperfilamentextrusion.Asyou’velearnedmultipletimesinthisbook,extrusionisthekeytoFFF3Dprinting.However,theslicingsoftwarehastomakealotofcalculationsbasedonmanyparametersinordertodeterminehowmuchfilamentneedstobeextruded.Forthe
mostpart,theslicingsoftwareisgoodatthesecalculations,butwithsomanyparameters,it’seasyforonesmallerrortoresultinafailedprint.
OverextrusionOverextrusioniswhentoomuchfilamentispushedthroughthenozzle.Itusuallycausesthesurfaceoftheprinttolooklumpy,uneven,and
sloppy.Thisisalmostalwayscausedbyasettingthatwasenteredincorrectlythough,insomeveryrarecases,itcouldbeahardwareproblem.
Overextrusioncausessurfacequalityproblems,likethebubbling
aroundtheoctopus’seye.
Themostcommonsettingthatcausesthisproblemisthefilamentdiameter.Inorderto
fixthis,youhavetoactuallymeasureyourfilament’sdiameter(preferablyinmultipleplaces)inordertogetanaccuratenumber.Othersettingsthatcancausethis:theextrusionmultiplierbeingsettoohigh,thenozzlediameterbeingsettoosmall,manualextrusionsettings(trychangingthemtoauto),andtheextruderstepspermm(yourextrudershouldbecalibrated).
UnderextrusionTheoppositeofoverextrusionisunderextrusion,whichiswhentoolittlefilamentisextruded.Theeffectofunderextrusionisusuallyvisiblegapsbetweenlinesoffilament.Inextremecases,thiscancauseacompletefailureofthepart,becauselayersdon’tadherewellenoughtoeachother.
Underextrusionmakesthefilamentstrandstoothin,causinggaps,asyoucanseeinthisprintoutofan
octopus.
Thecausesofunderextrusionareprettymuchthesameas
overextrusion.Itwilljustbeintheoppositedirection.Forexample,ifyousetyourfilamentdiametertoolow,itwillcauseoverextrusion.But,ifyousetittoohigh,itwillcauseunderextrusion.Thesolutionissimple:measureyourfilament’sdiameterandenterthat.
Jamming
Themostdrastic(andobvious)extrusionproblemisjammingorclogging.Eithertheprinterwillstopextrudingaltogether,intermittentlystopextruding,orextrudethinandunevenlinesoffilament.Thisusuallyendsupcompletelyruiningthepart.
Jamsusuallyhappenwhenthefilamentgetstwistedupinthecoldend.Thisiseasyenoughtofixbyjustpulling
itout,cleaningoutthecoldend,andstartingover.Clogsinthenozzlearemoredifficulttodealwith.Theyusuallyhappenwhenthehotendtemperatureistoolow,dustordirtgetsintothehotend,orthequalityofthefilamentislow.
Jammedextrudersandcloggednozzlescancausetheprintertostopextrudingcompletely.Thiswillcausesurfacestobethininsteadofsolid,asyoucansee
withthispart.
WATCH OUT!Low-quality filament,
especially in dark colors, isoften difficult to melt andextrude properly. There isjust too much nonplasticjunk in the filament, and itcauses the nozzle to clog.
WhenyournozzlebecomescloggedwithABS,thebestsolutionistoremoveitandsoakitinacetoneinorderto
cleanitout.ForPLAorothermaterials,youcanheatupthehotendandstickapieceoffilamentintoit.Allowittocooltoabout150°C,andthenpullthepieceoffilamentout.Youmayneedtorepeatthisafewtimes,butyoucanusuallypullouttheclog.
Poor DimensionalAccuracy
Youmaynoticethatyourpartsarecomingoutwiththedimensionsslightlyoff.Oryoumighttrytofittwoprintedpartstogetheronlytofindtheydon’tfit.Thereareusuallythreepossibleculprits:
Yourstepsaren’tcalibrated.
Somepartofyourdrivesystemisloose.
Theslicerisn’thandlingtheslicingcorrectly.
Whenitcomestothefirstissue,eachaxishastohavethenumberofstepspermillimetercalibrated.Ifit’snotright,thelengthsonthataxiswillbetooshortortoolong.Mostpeoplenoticethiswhencircularfeatures(likeholes)endupcomingoutasovals.That’sbecauseoneaxisismovingtoofar(ornotfarenough),causingthecircletobecomeelongated.Youcanfindtheinformation
forcorrectcalibrationfromthemanufacturerofyour3Dprinteroroncommunityforums(seeAppendixB).
Intermsofthesecondissue,thedrivesystembecomingloosecancauseunintendedmovement,resultinginpooraccuracy.Fixingthisisusuallyasimplematteroftighteningupallofyourscrewsandmakingsureyourbeltsareniceandtaut.
Andfinally,themostfrustratingcauseistheslicingsoftwareitself.Theshapeofthefilamentasit’sdepositedisfairlydifficulttoaccountformathematically,andmanyslicersdon’tquitegetitright.Thiscanmakeyourpartslightlytoobig(usuallybyafractionofamillimeter).Theonlyrealsolutiontothisistotryanotherslicerortoturndownyourextrusionmultipliersettinginorderto
slightlyunderextrudeandmakethepartsmaller.
TemperatureProblemsThetemperaturesofthehotendandheatedbedbothplayimportantrolesinthequalityoftheprintedpart.Pretty
obvious,right?Butit’snotalwaysobviouswhenatemperatureproblemistheculpritforaparticularproblem,soI’mgoingtocoverwhatcommontemperature-relatedproblemslooklike.
Hot End Is Too HotThefilamenthastobemeltedjustenoughtoflowfreelyout
ofthenozzlebutstillhastobeabletoquicklycoolonceit’sbeendeposited.Ifthehotendistoohot,thefilamentwon’tcoolquicklyenough.Theeffectisthattheparttendstolookslightlymelted(thoughitmayonlylookthiswayincertainspots).Thesameproblemcanoccurifthelayerissmall,becauseitdoesn’thavetimetocoolbeforeanewlayerisadded.
Ifit’sconsistent(notjustonsmalllayers),youcanturnyourhotendtemperaturedown.Ifit’sjustonsmalllayers,youcanuseafanforcoolingorslowdownsmalllayersinyoursettings.
Ifthehotendistoohotorthelayersaresmallwithoutadequatecooling,thepartwilldevelopameltedappearancelikethetopof
thisone.
HOT TIPExtreme hot end
temperature problems areoften caused by problemswith the thermistor. This isusually either because thethermistor has failed or hascome loose. If it’s loose, itcan be affixed with Kaptontape. If that’s not theproblem, the thermistor canbe replaced. (They’reusually only a few dollars.)Contact the manufacturer forinformation on replacing the
thermistor and to see if it willbe covered under awarranty.
Hot End Is TooColdIfthehotendistoocold,ittendstoproduceresultssimilartonozzleclogs.Eitherfilamentwon’textrudeatalloritwillextrude
inconsistently.Allyouhavetodoissimplyturnthetemperatureofthehotendup.
Whenthehotendtemperatureistoolow,itresultsininconsistentextrusion.Thispartshowshowmessythisissuecanlook.
Cracking of Part
Due to CoolingApartcrackingisacommonproblemwhenyouprintlargepartsinABS.ThisisbecausetheABScoolsandcontracts,splittingtheparthorizontallybetweenlayers.Whilethisisadifficultproblemtoovercome,thereareafewpotentialwaysyoucantrytoavoidthis.
Becauseprintfansandeven
draftsintheroomcancoolapartandcausecontractionsthatleadtocracks,onesolutionistokeepthepartfromcoolingoffasmuchaspossible.Enclosures(especiallyheatedenclosures)arethebestwaytoovercomethis.However,ifthat’snotfeasibleforyou,youcantryusingatallskirttoactasashieldaroundtheprint.Anotheroptiontoavoidcracksistodesignthepart
itselfsoitdoesn’thaveanylong,tall,horizontalsurfacesinordertoreducethestressfromcontraction.
Thecontractionoftheplasticasitcoolscancauseaparttocrackhorizontallybetweenthelayers.
Discoloration ofFilament Due to
HeatIfyou’reusingalight-coloredfilament(especiallywhite),youmaynoticethepartbecomesdiscolored.Thisiscausedbyheat,eitherfromtheheatedbedorthehotend.
Ifit’sjustonthebottomofthepart,it’stheheatedbed;ifit’severywhere,it’sthehotend.Inbothcases,itcouldsignalthetemperatureis
dramaticallytoohigh,meaningyoushouldturndownthetemperature.Sometimeswiththehotend,however,yourextrusionspeedmaybetooslowandthefilamentcouldbesittinginthehotendtoolong.Ifthat’sthecase,tryspeedingupyourprints.
AdhesionProblemsYou’velearnedinpreviouschaptershowimportantitisforthefilamenttostickwelltothebed.Thosetimeswhenitdoesn’tcanbeabigheadacheforyou.Formostpeople,adhesionproblemsarethebiggestsourceoffrustrationin3Dprinting.
Thisisbecausetherearesomanypotentialcausesandsomanypotentialsolutions.Here,youlearnwhattheresultsofpooradhesionareandwhattodoaboutthem.
WarpingThesamecontractionthatcausescrackingalsocausestheparttowarp.Thisisusuallymadeevidentwhen
thebottomofthepartcurves(especiallyattheedges).Thiscanbesolvedthesamewayascracking—enclosuresanddesignsthatlimitlong,horizontalsurfaces—butyoucanalsodramaticallyreduceitbyincreasingbedadhesion.
ThecontractiononthisABSpartcausedextremewarping.
Toincreaseadhesionbetweenthefirstlayeroffilamentandthebed,takealookatthesurfacetreatmentoptions
mentionedinChapter8.Heatedbedshelpalot,aswellastapes,films,glue,andevenhairspray.
Part Comes LooseIfyoursurfaceadhesionisreallypoor,theentirepartmightcomeoffthebedduringtheprint.Usually,thishappenswhenyourZheightistoohigh,orwhenyoudon’t
haveanysurfacetreatmentsatall.Ifyou’reusingthepropersurfacetreatments,tryloweringyourZheightalittlebittofixthisissue.
FASCINATING FACTAuto-leveling systems
do a very good job ofalleviating problems causedby improperly adjusted Zheights, because they allowyou to set exactly how high itshould be in the software.
Even if your 3D printer didn’tcome with auto-leveling, it’spossible that it could beavailable as an upgrade. Ifyou’re having frequentproblems with setting the Zheight on your printer, itmight be worth checking tosee if that’s an optionavailable to you.
Part Breaks DuringRemoval
Sometimesyourpartmightactuallysticktoowell.Thiscancausetheparttobreakduringremovaloreventobreakglassbedsinextremecases.
ThisparticularproblemisoftencausedbyoveruseofABSjuice/glue—acaseofgoingalittleoverboardwithasurfacetreatment.YoushouldonlyuseathinlayerofABSjuicetoavoidthis.However,
goodadhesionisn’tabadthing,soanotheroptionistotryusingaflattooltoprythepartoffwithoutbreakingit.
Other PrinterProblemsSomeproblemsjustdon’tfitneatlyintoapredefinedcategory.Thesearetheissues
thattendtocomeoutofleftfieldandoftenthrowyouforaloop.Mostofthesewon’tresultinacompletefailureoftheprint,butthey’restillirritatingandaffectthequalityofthepart.
BlobsIfyounoticelittleblobsofplasticonthesurfaceofthepart,it’susuallycausedby
eitherlackofretraction,overextrusion,orahotendthat’ssettoohigh.
I’vealreadycoveredsolutionsforthelattertwocauses,andthefirstoneiseasyenoughtofixinyoursettings.Simplyturnonretractioninyourslicersettings(1mmto2mmusuallydoesthetrick).
Stringing
Stringinglookslikeyou’dexpect:thinstrandsoffilamentbetweenfeaturesonthepart.Thecausesforthisarelackofretractionorthehotend’stemperaturebeingsettoohigh.Thiscanbesolvedbyturningonretractionorloweringthetemperatureofthehotend.
Turningonretractionwillusuallyfixstringingproblemslikewhat’s
shownonthisrobot.
DroopingBridgesarefeatureswherea
newlayerisplacedoveremptyspace.Forthesefeatures,theprinterhastoextrudefilamentacrossthechasmfromonesolidtoanother.Ideally,theseshouldturnoutniceandflat.Butifyounoticethey’redrooping,it’susuallycausedbyalackofcooling.Youmightalsoseethissameproblemhappenonotheroverhangingfeatures.
Usingaprintfanwilldoalottoreducedroopingonbridgesandoverhangssimilartothis.
Tofixthis,youneedtomakesureyourprintfanisturnedon.Ifyoudon’thaveaprintfan,you’llhavetoaddone.Ifthefanisonbuttheproblem
stilloccurs,youshouldmakesureit’sturnedallthewayup.Ifit’sstilloccurringevenafterthat,youshouldlookintoprintablefanshroudsforyour3Dprinter,whichmoreeffectivelydirecttheairfromthefantothepart.
GhostingGhostingiswhenfaintlinesappearonthesurfaceoffset
aroundfeatures,somethingusuallyonlyvisibleonfairlyflatsurfacesthatarenexttoperpendicularfeatures.It’scausedbyvibrationsfromtheweightoftheextrudercarriageasit’smovingbackandforth.
Ghostinglikeyouseeonthispencilholdercanusuallyonlybefixedby
reducingprintspeedand/oracceleration.
Theonlywaytofixthiswithoutmodifyingyour
printer’shardwareistoslowdowntheprintspeedortoexperimentwiththeaccelerationsettings.Theaccelerationsettingsmightbehiddeninanadvancedareaofyourslicer’ssettings,buttheydeterminehowfasttheprintercanspeedupandslowdownasitmovesanaxis.Loweringtheaccelerationwillallowtheprintertostillmovequicklyonlongstretchesbutwillmakethechangesindirection
lessabrupt.
The Least YouNeed to Know
Incorrectsettingscaneasilyintroducemanydifferentkindsofprintqualityproblems.
Mostprintqualityproblemscanbefixedbytweakingtheprintsettings.
Inextremecases,badprint
settingscanresultinacompletefailureoftheprint.
PROJECT
1
CarabinerProject Time: 30minutesInthisproject,you’llbegettinghandsonandprinting
yourveryfirstpart.Foryourfirstprint,let’sstartwithsomethingquickandeasy:aone-piececarabiner.Thismodelshouldprintquickly,andmostprinterswillhaveitfinishedinunder20minutes.
Beforeyoubegin,makesureyou’vedownloadedthemodelpackfromtheIdiot’sGuideswebsite(idiotsguides.com/3dprinting)andhaveunzippedthefolder
soyoucanaccessthefiles.Forthisprojectandthesubsequentprojects,I’llbeusingRepetierHostandSlic3r,becausebotharefreeandpopularprograms.However,ifyou’dprefertouseothersoftware(oryourprinterrequiresit),thestepsshouldstillbeprettysimilar.
Preheat the
Extruder andHeated BedStartbyopeningRepetier(orwhateverhostsoftwareyou’reusing)andconnectingtoyour3Dprinter.Oncetheconnectionhasbeenmadebetweenyourhostsoftwareandyourprinter,clickontheManualControltabtogettothetemperaturesettingsfor
theextruderandheatedbed,whichyou’llnowbeginpreheating.Ifyou’reprintinginABS,theextrudershouldbesetatabout230°Candtheheatedbedshouldbesomewherebetween80°Cto100°C.ForPLA,theextrudershouldbe200°Candtheheatedbed(ifyouhaveone)shouldbebetween50°Cto70°C.
Preheattheextruderandheatedbedtotheappropriatetemperatureforthematerialyou’llbeusing.
Load the.STL File
Whiletheextruderandheatedbedareheatingup,goaheadandloadthe.STLfileforthecarabinerandsliceit(foundatidiotsguides.com/3dprinting).Todothis,lookforabuttoninyourhostsoftwarethatsaysLoadorOpen.Pushthatbutton,andthenfindandselectthecarabiner.stlfile.Slic3r,whichrunswithinRepetier,willdisplaythe3DmodelintheObject
Placementwindow.
TheObjectPlacementtabwilldisplaytheloaded3Dmodel.
Thegrayboxintheviewerwindowcorrespondstoyour3Dprinter’sprintareaandisbasedonthesettingsyou
enteredwhenyousetupthehostsoftware.Thecarabinerisasmallpartthatisonlyafewincheslong,soitshouldbeprintableonvirtuallyevery3Dprinteronthemarket.
WATCH OUT!If the model shows up
very large (compared to thegray box), either your printersettings for the print area arewrong or you have yourunits set to inches (it shouldbe in millimeters).
Slice the
ModelWiththemodelloaded,youcangoaheadandsliceit.Withasimplepartlikethis,theparticularsettingsyouusewon’tbecrucial.However,makesureyouhaveatleasttwoorthreeperimeters(includingtopandbottom)andatleasta50percentinfill.ThiscanbemodifiedbygoingtotheSlicertaband
clickingonConfiguration.Oncethere,clickthePrintSettingstabandfillintheinformationifnecessaryundertheLayersandPerimetersandInfillsubsections.Yourprinttemperaturesettingsshouldbethesameaswhatyoupreheatedtheextruderandheatedbedto.
Checktobesureyouhaveatleasttwoorthreeperimeters(includingtopandbottom)andatleasta50
percentinfill.
Withyoursettingsentered,youcanstartslicingthemodelbyclickingSlicewithSlic3r.Howlongittakesto
slicedependsonyourcomputerandthesliceryou’reusing,butitshouldn’ttakemorethanafewminutes.
Slicingasmallmodellikethisshouldonlytakeafewminutes.
Load the
FilamentAlotofpeoplekeepthefilamentloadedallthetimeandonlychangeitwhentheyrunoutoffilamentorswitchtoadifferentmaterialorcolor.Butifyouhaven’tloadedanyfilamentyet,loaditintotheextrudernow,whiletheslicerisrunning.
Howyouloadthefilamentdependsonthespecific
extruderyourprinterisequippedwith.Someofthem,liketheGreg’sWadeReloadedI’musing,havethumbscrewsandalatchthatneedstobeopenedup.Othershavealeverthatneedstobepushedtoreleasetensiononthebearing.Oritcouldbeacompletelydifferentmechanismaltogether.
However,nomatterwhatkindofmechanismitis,the
processisaboutthesameonceyouhaveitopen:
1.Trimtheendofyourfilamentwithscissorsatanangle,sothereisapoint(thishelpsitslideintothehotend).
2.Pushthefilamentintotheholebelowthehobbledboltordrivegear.Withthehotendheatedup,youshouldbeabletopushitinuntilmeltedfilamentstarts
comingoutofthenozzle.
Loadthefilamentbyopeningthemechanismandslidingthefilament
intothehotend.
Extrude
SomeFilamentOnceyou’veclosedthemechanism,switchbackovertotheManualControltabinyourhostsoftware.Thereshouldbeabuttontoextrudeaspecifiedamountoffilament,whichyoucanseeinthefollowingfigure.Extrude10mmor50mmof
filamentinordertoverifythefilamenthasbeenloadedproperlyandtobuildupsomepressureinthehotend(whichhelpsimproveflowwhileyou’reprinting).Thisisn’tabsolutelynecessarytodo,butithelpstomakesureeverythingisworking.
Extrudeasmallamountoffilamenttomakesureit’sloadedproperlyandtobuildpressureinthehot
end.
Whenyouextrude,youshouldhavefilamentcomeoutofthenozzlesteadilyina
consistentsize.Ifit’serraticorcomesoutatanangle,somethingmaybewrong.(Ifyourunintothisoranyotherproblems,besuretocheckChapter15,whichcoverstroubleshooting.)Onceyou’vedeterminedthatthefilamentisextrudingcorrectly,youcanpulloffthepileoffilamentwithapairofpliers,beingcarefulnottoburnyourselfonthehotend.
Makesurethatthefilamentextrudesconsistently,andthen
removetheplastic.
Start the
PrintNowit’stimetogoaheadandstarttheprint!GoovertothePreviewtab,whichgivesyouestimatesontheprinttimeandhowmuchfilamentisneeded(inmillimeters).TheviewerwindowshowsyoutheG-codepathstheslicergenerated,soyoucangetanideaofwhattheprinterwillactuallybedoingfromlayer
tolayer.
CheckthePreviewtabtomakesureeverythinglooksright,and
thenstartprinting.
Ifeverythingappearstobecorrect,pushStartPrint.Dependingonthesoftwareandsettings,theprintermay
notdoanythingimmediately.Sometimesitwillwaittomakesurethetemperatureissteadybeforeitbegins.Oncethat’sdone,though,itshouldhomeeachoftheaxesandstartprinting.
Watch theFirst Layer
Payverycloseattentiontothefirstlayerbeingprinted.Thefirstlayeristhemostimportantone,becauseit’sthefoundationfortherestofthepart.Ifthefirstlayerisright,thechancesaregoodthepartwillturnoutright.You’relookingtomakesureyouhavegoodadhesion,withoutsquishingthefilamenttoomuch.Youalsowanttomakesuretheflowoftheextrusionissteadyand
consistent.
Paycloseattentiontothefirstlayer,becauseit’sthemost
importantone.
HOT TIPI have my slicer set up
to do a couple of loopsaround the part before itactually starts printing thefirst layer of the part. Thepurpose of this is to get thehot end flowing before itactually gets to the part, so Ican see that the filament isadhering nicely all the wayaround (meaning the bed islevel) and that the partactually fits on the bed. Irecommend doing this foryour prints as well.
Afteryou’veensuredthefirstlayerisgood,youcansitbackandrelax.However,it’sstillagoodideatocheckontheprinteverynowandthentomakesuretherearenoproblems.
Let the PartCool
Tento20minuteslater,yourcarabinershouldbedone!Iknowit’stempting,butresisttheurgetoimmediatelyyankoffthepart.Youwanttogiveitfiveminutesorsotofinishcoolingofftomakesuretheplastichasfinishedhardening.
Yourfirstprintisdone.Takeaminutetoadmireyourwork!
Remove the
PartOnceyou’vetestedyourpatiencebylettingthepartcooloff,it’stimetoremoveit.Ifyoucan’tgetagriponthepart,youcanuseaflattooltopryitupfromthebottom.Becareful,though;it’seasytobreakthepartiftheadhesionisgood.Youmayneedtoworkatitfromdifferentsidestogetitoffthe
bed.
Aflattoolcanbeusedgentlytoremovethepartifit’sstuckonthe
bed.
Ifyou’rehavingareallyhardtimegettingitoff,giveitsomemoretimetocool
down.Oncethebedandtheparthavecooleddowntoroomtemperature,itshouldbealoteasiertoremove.
Enjoyyourfirstprint,andspendsometimecontemplatingthefactyoujusthadarobotdoyourbiddingtocreateaphysicalobjectfromscratch!
Congratulationsonyourfirstpart!Thefutureisnow!
PROJECT
2
PencilHolder
Project Time: 4hours
Inthisproject,you’llbesteppingupthedifficultyabit.Printingapencilholderrequiresacoupleoftrickstoaccomplish.Asyou’llnoticeonceyouopenthefile,themodelissolidanddoesn’topenlikeacup.Inordertouseitasapencilholder,theSlic3rsettingsmustbemodifiedtoremovethetopandmaketheinsidehollow.Thisshouldgiveyouanideaofhowpowerfultheslicing
softwareisandhowitcanbeusedtocustomizethemodel.
Load the.STL File andResize theModel,If Necessary
InRepetier,clickLoadandselectthepencil_holder.stlfile,whichisincludedinthemodelpackattheIdiot’sGuideswebsite(idiotsguides.com/3dprinting).Next,checkitssizeontheObjectPlacementtab,whichshouldalreadybeup.Thismodelisalotlargerthanthelastone,soyoushouldmakesureitfitsonyour3Dprinter.
Ifitdoesn’tfit,youcantry
resizingthemodel.OntheObjectPlacementtab,youshouldbeabletoselecttheloadedmodel.Youhavetheoptiontodobasicmodification,likerepositioning,rotating,andresizingthemodel.
Youcanresizethemodel,ifnecessary,intheObjectPlacement
tab.
WATCH OUT!While you can resize to
fit on your printer, keep inmind that it can’t be toosmall. Otherwise, it won’t bevery useful as a pencilholder.
Preheat theExtruder and
Heated Bed,and Load theFilamentMakesureRepetierisconnectedtoyour3Dprinter.Justlikeinproject1,youmaywanttostartbygettingtheextruderandheatedbedwarmedup.Ifyourecall,ABSrequiressettingsof
230°Cfortheextruderandbetween80°Cto100°Cfortheheatedbed,whilePLArequiressettingsof200°Cfortheextruderandbetween50°Cto70°Cfortheheatedbed(ifyouhaveone).BothABSandPLAworkwellforthismodel,soyoushouldbefineusingwhicheveryouhaveonhandorprefer.
Oncetheextruderisuptotemperature,loadthefilament
intothehotend,ifyouhaven’talready.Thestepsfordoingthisareexactlythesameasinproject1,socheckthatoutifyouneedarefresher.
Modify theSlicerSettings to
Make theModel a CupForthismodel,youhavetomakeacoupleofchangestotheSlic3rsettingsinordertoremovethetopofthemodelandmakeithollow;otherwise,itwon’tfunctionverywellasapencilholder.
InRepetier,gototheSlicertabandclickthe
Configurationbutton.(Seeproject1ifyouneedarefresher.)Oncetheconfigurationwindowopens,underthePrintSettingstab,locateandclickonLayersandPerimeters.Here,youwanttochangethenumberofhorizontalandbottomperimetersto4.Thenchangethenumberoftopperimetersto0.Thisgivesthebottomandsidesofthemodelasolidthicknessof4layersand
removesthetopofthemodelentirely.
Turnoffthetopperimeters.
Next,clickonInfill,whichislocatedbelowLayersandPerimeters,andchangethefilldensityto0%.This
makestheinsideofthemodelhollow.
Setthefilldensityto0%.
Slice theModel
WithyourSlic3rsettingsmodifiedtomakethemodelcuplike,youcangoaheadandslicethemodel.GototheSlicertabandclickSlicewithSlic3r.Thisprintshouldtake2to4hoursatthestandardsize,dependingmostlyonhowfastyourprintermoves.
HOT TIPThe actual slicing
process might take a fewminutes, so be patient here,especially if your computeris a bit older.
Start thePrintAftertheslicinghasbeencompleted,clickonthePreviewtab.Youshouldseethattheprojectedextrusionpathsmakeapencilholderinsteadofjustasolidmodel.Thisisbecausethepreviewwindowshowsyouwhatissupposedtobeprinted,not
theoriginalmodel.
Checkthepreviewtoverifyiftheprintlooksright.
Ifyou’rehappywithpreviewandtheextruderandheatedbedareuptotemperature,youcanstartprintingby
clickingStartPrint.
Watch theFirst LayerAsyoushoulddowitheveryprint,stickaroundtowatchthefirstlayer.Thefirstlayeristhemostimportant,somakesureitturnsoutright.Youwantgoodadhesion,but
youdon’twantthehotendsoclosetothebedthatitsquishestheplastic.
Printingthefirstlayer.Alwayscheckthefirstlayertomakesureit
lookscorrect.
Remove the
PartOncetheprinthasfinished,giveitatleastfiveminutestocooloff,soitcancompletelyharden.Lettingtheheatedbedcooldowntoroomtemperaturemakesitmorelikelythatthepartwilljustpoprightoff.Butifyou’reeagertostartstoringyourpencilsinstyle,youcanuseatooltoremovethepencil
holder.Justbesuretodothisgentlytoavoiddamagingthebedorthepart.
Youcanuseatooltocarefullyremovethepartfromthebed.
Withthepartremoved,youcanadmireyourhandiwork.Totestitandmakesureitworks,placesomepencils(or
evenpens)init.Iftheydon’tfallout,thencongratulations,youhaveapencilholder!
Itholdspencils!
PROJECT
3
RobotProject Time: 4hoursForthisproject,you’regoingtobeprintingarobotfigurine
modeledbyNathanDeas.Whatmakesthisabittrickierthanthepreviousprojectsistheprintwillrequiretheuseofsupports.Thismodelhasalotofoverhangingfeatures,soremovablesupportmaterialhastobeusedtoholdupthosefeaturesduringprinting.Aftertheprinthasfinished,however,youcanremovethesupports.
Load the.STL FileAsusual,startbyloadingthemodel.InRepetier,clickLoadandselecttherobot.stlfile,whichisincludedinthemodelpackattheIdiot’sGuideswebsite(idiotsguides.com/3dprinting).Themodelshouldloadwiththerobot’sbackfacingdown,
butifit’snot,youcanrotateitusingthecircularrotatebuttoninthetop-leftcorner.
HOT TIPYou also have the
option of printing the modelwith the feet down. Printing itwith the feet down willreduce the amount of themodel that comes intocontact with the supportmaterial, which shouldimprove the surface quality
of the overall print. However,because the feet are small, itwill be less stable. Tocombat this, you’d want toprint with a thick brim inorder to ensure the modelstays upright throughout theentire print.
Preheat theExtruder and
Heated Bed,and Load theFilamentWiththemodelloaded,it’sagoodideatosettheextruderandheatedbedtothetemperaturesyou’llusewhenyouprint.ThismodelshouldturnoutwellinbothABSandPLA,sofeelfreetouseeither
one.Justkeepinmindthattheextruderandheatedbedneedtobesetatdifferenttemperaturesdependingonwhichmaterialyouuse(seeproject1forthetemperaturesnecessaryforABSversusPLA).
Ifyourfilamentisn’talreadyloaded,youshouldloaditoncetheextruderisuptotemperature;project1cangivearefresheronthesteps
todothis,ifyouneedthem.Ifyou’rechangingfilamentmaterialsorcolors,besuretoextrudeatleast100mmoffilament.Doingthiswillbasicallyflushouttheoldfilament.
Modify theSlicer
Settings forSupportsBecausethismodelrequiressupports,youneedtochangeafewsettingsfromthepreviousprints.Themostimportantoftheseisturningonsupportgeneration.Thistellstheslicertocreatesupportswherenecessary.
Dependingontheparticular
sliceryou’reusing,thesupportsettingsmayvary.Ifthereisasimpleautomaticsetting,startwiththat.Otherwise,youwanttotellittogeneratesupportsforoverhangswithanangleover45°.Fornow,leavetherestofthesupportsettingsattheirdefaults.Gettinggoodsupportstakesalotofexperimentation,sostartwithsomethingsimpleandthenrefinethesettingsonfuture
prints.
InRepetier,generatingsupportsettingsisjustasimpleclickofGeneratesupportmaterial.
Otherthanthesupportsettings,youalsowanttomakesureyourfilament
diameterissetcorrectlyinordertomakesurethesupportsconnectjustwellenoughtothepart.Filamentisrarelyexactlytherightdiameter,soit’sbesttouseapairofdigitalcaliperstomeasure.Evenbetter,measureinthreeorfourdifferentplacesonthefilamentspoolandthenaveragethenumbers.Youcanthenchangeyourfilamentdiametersettingby
clickingConfigurationandthengoingtotheFilamentSettingstabtomatchtheactualdiameterofthefilament.
TheFilamentsubsectionoftheFilamentSettingstabhasaplacewhereyoucanadjustthefilament
diameter.
Also,ifyou’reusingPLA,makesureyouturnonyour
printfan.You’llfindthesettingstoturnonthefanintheCoolingsubsectionoftheFilamentSettingstab.ThisisalwaysagoodideawhenprintingPLA,butit’sespeciallyimportantwhenusingsupportmaterial.Withoutafanrunning,supportmaterialmightsticktoowelltothemodelwhenprintinginPLA.
TheCoolingsubsectionoftheFilamentSettingstaballowsyoutoturnonandadjustthefansettings.
Slice the
ModelOnceyou’veupdatedyoursettings,youcanslicethemodel.GototheSlicertabandclickSlicewithSlic3r.Thisparticularmodelcouldtakeanywherefrom2to4hourstoprintatitsdefaultsize.
HOT TIP
If you don’t want to wait thatlong (who does?), you canscale down the model tosomething smaller.However, if you do scale themodel, keep in mind thatsmaller features may notshow up well on someprinters. Luckily, this figurinedoesn’t have many finefeatures, so you should beable to scale it to 50 percentor so without any issues.The eyes may not show upwell, but everything elseshould.
Start thePrintAftertheslicinghasbeencompleted,clickonthePreviewtab.Youshouldseethemodeloftherobotonitsback,aswellasthesupports.Ifyou’resatisfiedwiththesettings,supportgeneration,
andprinttime,goaheadandclickStartPrint.
Afterslicingtherobotmodel,thepreviewwindowshouldshowyouwheresupportswillbegenerated.
Watch the
First LayerAsalways,paycloseattentiontothefirstlayertomakesureyou’regettinggoodadhesionbetweenthefilamentandthebed.
Thefirstlayerforthisprintmaylookalittledifferentthantheprevioustwo.I’musingabrimonthisprinttoincreasethesurfaceareaofthefirstlayertohelpwith
adhesion,whichiswhythereisalarge,flatareaaroundthemodel.(Formoreinformationonbrims,checkoutthe“PrintSettings”sectionofChapter13.)Butyoumayalsonoticealotofsmall,jaggedlinesoffilamentaround.Theselinesarethebaseofthesupportmaterialtheslicergenerated,whichisnormal.
Withthisfirstlayer,youcanseethebaseofthesupportmaterial.
Remove the
PartOncetheprinthasbeencompleted,youmaynoticeitdoesn’treallylooklikearobot.Thisisbecausethemodelispartiallysurroundedbysupportmaterial,whichhastoberemoved.Butfirst,theprinthastoberemovedfromthebed.
WATCH OUT!While the full-size
model should be done afterroughly three hours, youshould check on how it’sdoing once or twice everyhour. Especially for longprints like this, you don’twant to wait until the end todiscover there was someproblem.
Thefinishedprintwithsupportsshouldlooksomethinglikethis.
Youcanuseyourhandsoratooltoremovethepartfromthebed,whichshouldbeeasiertodooncetheparthas
cooled.Becausethereissomuchsupportmaterial,don’tbetooconcernedifpartsofitbreakoff.Thesupportmaterialisdesignedtodothat,soit’snotabigdeal(aslongastheactualmodelstaysintact).
Waitfortheprinttocool,andthenremoveitfromthebed.
Remove the
SupportsAfteryou’vewrestledtheprintloosefromthebed,it’stimetogothroughthesomewhattediousprocessofremovingthesupports.Thesupportsareconnectedtothemodel,buttheslicerattemptstomakethatconnectionasfragileaspossible.Ideally,thesupportswilljustpoprightoff.Butunfortunately,
therealityisn’tusuallyquitesosimple.Instead,you’llprobablyneedtousesomeplierstograbthesupportsandworkthemoff.
Apairofplierscanhelpyouremovethesupportsfromthe
model.
Itcantakesometimetoremoveallofthesupportmaterialfromthemodel.Be
carefulnottodamagethemodel,andresisttheurgetouseahammerandchisel.Bepatientandtakeyourtimehere.Eventually,youshouldbeabletopulloffallofthesupportmaterial.
Therobotfigurinewithallofthesupportsremoved.
HOT TIPWith the supports
removed, you may notice
that the surface quality isn’tnearly as good in the areaswhere the supportscontacted the model. Thiscan be improved by fine-tuning your settings, butthere will always be someloss of quality here. For thisreason, designers generallytry to reduce thedependence on thesupports.
Nowenjoyyourfreshly
printedrobot,whichwasprintedbyarobot!Maybeyoucanprintawholerobotarmytodefendyourcubiclefrominvadingcoworkers?
Thefinishedrobotfigurine,readytofollowyourorders.
PROJECT
4
Storage Boxwith
Drawers
Project Time: 1 dayItwilltakequitesometimetoprintallofthepartsforthisproject.That’sbecauseyou’regoingtobeprintingfourpartsintotal:thebodyofthestorageboxandthreedrawers.Eachofthesepartswilltakeafewhourstoprint,soprintingthemisgoingtobeanall-dayaffair.
Butitwillallbeworthitin
theend.Thishandystoragesolutionwillgiveyournuts,bolts,andanyothertinyitemsacomfynewhome.
HOT TIPIn a later project, you’ll
learn how to design andprint your own customdrawers, so you’ll be able tostore whatever your heartdesires (so long as it’ssmall).
Open YourHostSoftware andLoad theStorage Body.STL FileStartbyopeningupyour
printerhostsoftware.Asusual,I’llbeusingRepetierforthesephotos.Butifyou’reusingothersoftware,theprocessshouldbeprettysimilar.Youcanalsopreheatthehotendandheatedbed,ifyouhaveone(project1providesarefresheronthetemperaturesnecessaryforABSversusPLA,ifyouneedit).
Next,clickLoadandselect
thestorage_body.stlfile,whichisincludedinthemodelpackattheIdiot’sGuideswebsite(idiotsguides.com/3dprinting).Thestoragebodyshouldbelyingonitsendbydefault,butifit’snot,youcanusetherotationtoolsintheObjectPlacementtabtoorientitproperly.
Thepartshouldbeorientedthiswaytoavoidtheuseofsupports.
Thepurposeoforientingthemodelthiswayistoavoidhavingtousesupports.Theslotsinthesidescanbe
printedwithoutsupportsbecausetheendsarecircular.Overhangsthataremoreverticalthan45°canusuallybeprintedwithoutsupports.Becausecirclesnevergetlessthanthat,youcansafelyassumethey’llprintwithoutsupports.
Circularfeatures,likeholesandslots,canbeprintedwithout
supports.Thisisbecausetheangleisneverlessthan45°,asyoucan
seehere.
Slice theStorage BodyNowit’stimetoslicethemodel.Thismodelwon’trequiresupportsoranyspecialsettings.However,youshouldmakesuretheinfillissetfairlyhigh,atleast50percent(seeproject2ifyouneedareminderofhowtosettheinfillpercentage).In
ordertoreducewarping,IalsorecommendyouprintthisinPLAandwithabrim.
Onceyou’vegotyourmodelorientedproperlyandyoursettingstweaked,gototheSlicertabandclickSlicewithSlic3r.Thiscouldtakeawhile,especiallyonslowercomputers.
Slicingthemodelcantakequiteawhile,sobepatient!
Print the
Storage BodyThenextstepisprettypredictable:you’regoingtoprintthepart.Butbeforeyoustarttheprint,clickonthePreviewtabandtakeamomenttocheckthemodeltoseeifitlookslikeit’ssupposedto.
Ifitisright,goaheadandpushthatStartPrintbutton!AsIalwaysdo,Irecommend
youstickaroundtowatchthefirstlayer.Ifthatoneprintscorrectly,thepartwillprobablyturnoutwell.
Ifitlooksright,printit.
Load theDrawer .STL
File and SliceItAfteryourfirstprinthasfinished,youcanpullitofftheprinterandgetstartedonthedrawers.Mostlikely(thoughitdependsonyoursettings),yourprinter’shotendandheatedbedturnedoffaftertheprintfinished.Iftheydid,youneedtopreheatthem
again.
Whilethey’reheatingup,youcanloadthestoragedrawermodelbyclickingLoadandselectingthestorage_drawer.stlfile,whichisincludedinthemodelpackattheIdiot’sGuideswebsite(idiotsguides.com/3dprinting).Thisoneneedstobeorientedwiththebottomdown,soit’sprettystraightforward;any
adjustmentscanbemadeusingthetoolsintheObjectPlacementtab.Thisprintwillalsousetheexactsamesettingsasthelastone.Onceyou’rereadytosliceit,gototheSlicertabandclickSlicewithSlic3r.
Orientthedrawerwiththebottomdown.
HOT TIPYou may want to use a
different color for thedrawers for some lovelycontrast. If you do, be sureto adjust the filamentdiameter settings to matchthe new filament.
Print the
DrawerIfeverythinglooksgoodaftertheslicinginthePreviewtab,youcanstarttheprintbyclickingStartPrint.Justlikewiththestoragebody,you’llwanttowatchthefirstlayertomakesuretherearenoobviousproblems.Youshouldthenletitcoolafewminutesbeforeremoving.
Asalways,makesurethepreviewlooksrightbeforetheprint,andwatchthefirstlayerafter.
Print Two
MoreDrawersIfthestoragebodyanddrawersturnedoutwell,you’llprobablywantacouplemoredrawerstoputintheothertwosectionsofthestoragebody.Todothis,youcanjustrepeattheprevioustwostepstoprinttwomoredrawers.Or,ifyou’refeeling
reallyadventurous,youcanhopovertoproject6tolearnhowtodesignyourowncustomdrawers!Eitherway,onceeachisdone,allowtocoolbeforeremoving.
Theprintedparts.Youcangotoproject6tolearnhowtomakeyourowncustomdrawerstouse
withthisbody.
PART
4
3D ModelingOnceyou’velearnedhowto3Dprint,you’llbeeagertoprintallofthecoolmodelsyoufindonline.Butitwon’tbelongbeforeyouwanttodesignyourownmodelsto
print.Inthispart,Iteachyouhowtodojustthat.YoulearnhowtouseCADsoftwaretocreateyourownmodels,andhowtooptimizethemfor3Dprinting.Youalsolearnaboutbasicreverseengineeringtechniques,soyoucanprintusefulpartsthatworkwithexistingproducts.
CHAPTER
15
Introductionto CAD
In This Chapter
HowCADdiffersfromother
kindsof3DmodelingCommonCADmodelingandsketchingcommands
WhyunitsandscaleareimportantinCAD
Computer-aideddesign(CAD)ishowvirtuallyallnewproductsaredesignedthesedays.CADsoftwareisusedtocreate3Dmodelsofthepartsofaproduct,whichcanbeusedtomakeeverystepofthedevelopmentand
productionprocessmoreefficient.Overthepast30yearsorso,CADhasliterallyrevolutionizedproductdesignanddevelopment.
Toreallytakefulladvantageof3Dprinting,you’llwanttolearn3DCADmodeling.It’snotaneasyskilltolearn,butit’snecessaryifyouwanttocreateyourowndesigns.Andlearningthebasicsshouldn’tbetoodifficult.In
thischapter,ItakeyouthroughallyouneedtoknowaboutCADfor3Dprinting.
Why CADCame AboutBeforetheintroductionofCAD,developinganewdesignwasaveryslowanderror-proneprocess.If
someonehadanideaforaproduct,thedesignhadtobedrawnbyhand.Justcreatingthedrawingintroducedthepossibilityofmistakes,andthat’sassumingthedesignwouldwork.Itwasn’tuntilthepartswereactuallymadethatthedesignercouldknowforsurewhethertheywouldevenfittogether,muchlesswork.
FASCINATING FACTMost modern
professional CAD systemshave add-ons for runningsimulations. Engineers canuse these simulations to testheat transfer, stressanalysis, load capabilities,and so on. With the properuse of simulations, thedevelopment process inmany industries has beenmade significantly moreefficient.
ModernCADsystemschangeallofthatanddrasticallyimprovetheprocess.3Dmodelscanbecreatedandusedtotesthowthepartsfittogether.Thosemodelscanevenbeusedinphysicssimulations,whichcantelltheengineeriftheindividualpartswillholduptothestressesinvolved,andiftheassemblyasawholewillwork.
Oncethe3Dmodelshavebeencreated,theycanbeusedtoquicklycreateaccurate2Dtechnicaldrawingsformanufacturing.Becausethosedrawingsarebasedonthemodels,thereislittleriskofinaccuracy.Creatingthosedrawingsisalotfasterthandrawingthembyhand,andtheycanbeautomaticallyupdatedifthe3Dmodelisrevised.
Inmanycases,likewhenthepartswillbe3DprintedorCNCmilled,thedrawingisn’tevennecessary.Instead,the3Dmodelscanbesentstraighttothe3Dprinter.Thismakesdrawingsunnecessaryintheprototypingstage(althoughmostcompaniesstillusedrawingsformanufacturing).
Basically,CADhasmadeeverystepoftheengineering
processbetter.Butit’snotjustengineersanddesignerswhocantakeadvantageofthebenefitsofCAD.Asa3Dprinteruser,you,too,canuseCADsoftwaretocreatedesignstoprint.
Asimpleflatpatterndesignedin2DCAD.
Artistic 3DModeling vs.CADSoftwareTechnicallyspeaking,CADisnotsynonymouswith3Dmodeling(thoughitisoftenimproperlyusedthatway).AgreatdealofCADworkis
donepurelyin2D,inwhichcaseit’ssimilartotraditionaldraftingbyhand(justusingacomputertodrawinsteadofapencil).Andconversely,notall3DmodelingisCAD.
DEFINITIONDrafting is the
process of creating technicaldrawings of parts andassemblies. A person whodoes this is a drafter (ordraftsman or draughtsman).Traditionally, this was donewith a pencil and paper, butit is now done almostexclusively with CADsoftware.
CADisatermusuallyusedinthecontextofengineering.CADsoftwareisgenerallyusedtodesignfunctionalpartsandassemblies.Thisisincontrastto3Dmodelingsoftwarethat’susedtocreateartisticmodelslikesculpturesandcharacters.
Sowhythedifferentiation?It’snotjusttheusagethatmakesthemunique;thesoftwareitselfisvastly
differentaswell.Becauseartistic3DmodelingandCADmodelingservecompletelyseparatepurposes,therespectivesoftwareisoptimizedforthosepurposes.
Artistic3Dmodelingsoftware,orsculptingsoftware,ismadetomakeiteasierforartiststodotheirjobs.Exactdimensionsarerarelyimportanttothem;instead,theyneedtobeable
tofreelyformthemodelsvisually.Theirgoalistocreateamodelwhichisaestheticinnature,sotheir3Dmodelingtoolsreflectthat.
CADmodeling,ontheotherhand,isallaboutcreatingmodelswithveryspecificdimensionsandadefinedform.CADdesignersdon’tapproachthisfromavisualperspective,butfroma
mathematicalone.Theaestheticsofthepartbeingdesignedcancertainlybeimportant,buttheystillhavetobespecificallydefined.
ThedifferinggoalsbetweenartisticandCAD3Dmodelingresultinafundamentaldifferenceinthewaythesoftwareworks.Artistic3Dmodelingsoftwareisfreeformandallowstheartisttocreateand
modifyshapes,points,andfaceswithoutnecessarilydefininganyparameters.Theartistcanjustsculptthemodelbasedonhowhethinksitshouldlook.
3DCADsoftwareisparametric,whichmeansthateveryshapeisdefinedwithspecificparameters(ordimensions).Technicallyspeaking,someshapescanbecreatedwithoutexplicitly
definingparameters,butdoingsoisgenerallyconsideredtobebadform.Andwhethertheuserdefinestheparametersornot,theyarestillcreatedbythesoftwareandcanbemodifiedlater.
HOT TIPIf you’d prefer to use
an artistic 3D modelingprogram instead of a CAD
program, Blender is a goodoption. It’s also free andopen source, and has ahuge user base and plentyof add-ons. It’s a very high-quality program, so much sothat it competes with theprofessional alternatives.However, it has a very steeplearning curve and is difficultto learn.
Theabilitytomodifyexistingparametersisprobablythe
mostimportantfunctionofCADsoftware.Becauseeveryfeatureyoucreateisdefinedbyparameters,thoseparameterscanbemodifiedtochangethemodel.Evenifit’stheveryfirstfeatureyoucreate,youcanstillchangeit,evenaftertherestoftheparthasbeenmodeled.
Fromadesignperspective,thistraitofCADsoftwareisinvaluable.Youcaneasily
adjustthedimensionsofthepartsasneededduringthedesignprocess.Parameterscanalsobelinkedtogetherwithmathformulas,sothatadjustingonedimensionautomaticallyupdatesothers.Usingthatfunctionality,youcancreateasinglemodelthatcanbeusedtoproducepartsinavarietyofsizes(forexample,nutsandboltsindifferentsizes).
CADSoftwareOptionsWhenitcomestoCADsoftware,thebestprogramsyou’llfindaretheonesmadespecificallyforengineering.ThethreemostpopularparametricengineeringCADprogramstodayare
Solidworks,AutodeskInventor,andPro/Engineer(whichhasbeenrenamedtoCreo).Theseareallgreatprograms,butbecausethey’remeantforprofessionaluse,they’reveryexpensive.However,theyoftenhavestudentversionsavailable,sothatcanbeworthlookingintoifyou’reastudent.
However,ifyou’renotastudentanddon’twantto
spendasmallfortuneonsoftware,therearestillsomeoptionsavailable.Inrecentyears,anumberofopen-sourceand/orfreeCADprogramshavebeenreleased,suchasFreeCAD,Tinkercad,andAutodesk123D.Theseareallusable,andfreeisahardpricetobeat,butI’vefoundthemtobeprettylackingincomparisontotheprofessionaloptions.Thatsaid,theyshouldbeadequate
forhobbyuse,especiallywhenyou’rejustgettingstarted.
AsidefromCADapplications,therearesomeother3Dmodelingprogramsyoumayfinduseful.Thesewon’tbeparametricliketheothers,butmanypeoplestillfindthemuseful.SketchUp,Blender,andWings3Daresomegoodexamplesyoumaywanttotryifyoufind
theCADworkflowdoesn’tworkforyou.
Anotherfree(andopen-source)optionisOpenSCAD,whichisveryuniqueamongCADprograms.Thedevelopersadvertiseitas“TheProgrammer’sSolid3DCADModeler,”becauseyoubuildthemodelbywritingascriptwhichdefinesthemodelinsteadofusingagraphicaluserinterface
(GUI).Itmaysoundstrange,butit’sproventobeverypopularwithpeoplewhoarecomfortablewithcode.
HOT TIPTry using a variety of
different programs to get afeel for what each offers.Even the programs thataren’t free will usually havefree trials available.This software is difficult tolearn, and it’s a good idea totry different ones todetermine which makes themost sense to you.
An Overviewof CommonCADProgramCommandsIdon’thaveroomheretocoverallofthecommandsusedinallofthevarious
CADprograms,butIwillcoversomeofthemorecommonones.Bearinmindthatthecommandnameswillvarydependingonthespecificsoftwareyou’reusing,butthebasicfunctionsofthecommandswillremainthesame.Thespecificmethodforusingthecommandswillalsodifferbetweenprograms,soI’llreallyjustbeexplainingtheirfunctionshere.
I’llbreaktheseupintotwosetsofcommands:modelingcommandsandsketchingcommands.Themodelingcommandsareusedtoaddnewfeaturestothemodel,whilethesketchingcommandsareusedtodefine2Ddrawingstousewiththosefeatures.
Modeling
CommandsExtrude:Thisisalmostdefinitelygoingtobethemostcommoncommandyou’lluse.Itsnameisderivedfromtheextrusionmanufacturingprocess,whichmighthelpyouunderstandwhatitdoes.(SeeChapter3forarefresherifyoudon’t.)Whenusingthiscommand,yousketcha2Dcross-section,whichisthen
extruded(perpendiculartothecross-section)toforma3Dfeature.
Extrudedcut:InsomeCADprograms,thiscommandiscombinedwiththeextrudecommand(youjustspecifythatit’sacut).Thisworksinthesamewayastheextrudecommand,exceptitremovesmaterialfromanexistingsolidbody(tocreateahole,forexample).
AnexampleoftheextrudedcutcommandinaCADprogram.
Revolve:Thiscommandallowsyoutocreateafeaturebyspinninga2Dcross-sectionaroundacentralaxis.
Youdefinehowmanydegreesitwillspin,andasolidbodyiscreatedbasedonthat.So,forexample,tocreateasphere,youcouldrotateahalf-circle360°.
AnexampleoftherevolvecommandinaCADprogram.
Revolvedcut:Justlikewiththeextrudedcut,thiscommanddoesthesamethingastherevolve,exceptit
removesmaterialinsteadofaddingmaterial.
Sweep:Asweepisalittlemorecomplicatedthantheextrudeandrevolvecommands.Thiscreatesasolidbytakinga2Dcross-sectionandsweepingitalonga2Dor3Dtrajectory(thepath).Thisrequiresasketchforthecross-section,aswellasanothersketchforthetrajectory.Thesweep
commandisoftenusedtocreatepipesandtubesbutcanbeusedforavarietyofpurposes.
Sweptcut:Youmaybenoticingatrendhere.Mostcommandsthatcancreateanewsolidalsohaveacounterpartforremovingmaterialfromanexistingsolid,sosweephasacounterpartinsweptcut.Thiscommandhasmanyuses,like
cuttingchannelsintoapart.
Loft:Thiscommandissimilartothesweepcommand,exceptyousketchtwoormorecross-sections(insteadofsinglecross-sectionandapath).Thismeansthecross-sectionalshapeofthesolidcanvaryalongitslength(forinstance,fromacircletoasquare).If,forinstance,youwantedtotransitionfromasquaretube
toaroundtube,youcouldusethiscommand.
Loftedcut:Asusual,theloftcommandhasamaterialremovalcounterpart.Ifyou’refamiliarwithaVenturi(likeinacarburetor),thisisthecommandthatcouldbeusedtocreatesuchafeature.
Hole:ManyCADprogramsalsoincludesomekindofholecommand.Youcouldreallymakethesamefeature
withtheothercommands,butthisoftensimplifiestheprocess.Often,specificationsforanumberofstandardfastenerswillbeautomaticallyloaded,allowingyoutoquicklycreateholesforthosefasteners.However,thefastenerthreadsaren’tusuallyphysicallymodeled;instead,avisualrepresentation(usuallyagraphic)isaddedalongwiththespecifications.
Thismeansthethreadsmadewiththistoolwon’tbe3Dprinted.
Fillet:Usethiscommandtocreateroundededges.Itcanbeusedonbothinteriorandexterioredges.Itisdefinedbasedontheradiusofacircle,whichistangenttobothfacesthatintersecttomaketheselectededge.
AnexampleofthefilletcommandinaCADprogram.
DEFINITIONIn geometry, a
tangent line touches a curve
at a single point andcontinues straight on fromthat point. The easiest wayto visualize this is to picturea circle. A tangent linetouching the far-right side ofthe circle will continue onvertically (up, down, orboth), touching just a singlepoint of the circle. The actualmathematics of defining atangent line are fairlycomplicated, but luckily theCAD software handles all ofthat—you only need to beconcerned with the practical
effect.
Chamfer:Thisissimilartoafillet,exceptitcutstheedgeinsteadofroundingit.It’susefulformakingedgeslesssharpwithoutroundingthem.It’sdefinedbasedonthedistanceit’scutinoneachface,oronedistanceandanangle(commonly45°).
AnexampleofthechamfercommandinaCADprogram.
Shell:Youcanusethiscommandtomakeasolidbodyhollow.Forexample,youcoulduseittomakea
cubeintoahollowbox(withonesideremovedandtheothersgivenathickness).Theshellcommandrequiresthatyouselectafacetoremoveanddefineathicknesstogivetotheotherfaces.Thisisveryusefulforcreatingpartslikeprojectenclosures.
Mirror:Thefunctionofthiscommandisprettystraightforward:itallowsyoutotakeafeatureandreflectit
acrossaplane.Youusethistocreatesymmetricalfeatureslikeboltholes.
Helix/spiral:Thisreallyisn’tamodelingcommandonitsownbutismoreofanintermediary.Thehelixcommandcanbeusedtocreatevariouskindsofspiralpaths,whichcaninturnbeusedtocreatethingslikespringsandthreads.
Plane:Thisisacommandfor
creatingareferenceplanein3Dspace.Itcanbeusedasamirroringplane,asaplanetoextrudefrom,orsimplyasadimensionreference.
Axis:Likeaplane,thisisusedforreference.Itcanbeusedfordimensioning,asanaxisfortherevolvecommand,orforcreatingotherreferences(likeplanes).
Point:Anotherreference,thisoneisusedtocreateasingle
pointin3Dspace.Forinstance,youcouldcreateapointattheintersectionofaplaneandanaxis.It’susefulforcreatingdimensions,andtouseasareferenceforotherfeatures.
Sketch:Mostfeatureswillrequirea2Dsketchtodefinetheircross-sections,andthiscommandallowsyoutocreatethatsketch.Asketchcanbemadeonanyplane;
onceyou’veselectedaplane,you’llhaveawholenewsetofcommandsthatareusedspecificallyfordrawing.
SketchingCommandsLine:Themostbasicofallofthesketchingcommandsisthehumblestraightline.It’sprettyself-explanatory:youuseittomakelines.Draw
fourlinesinasquare,andthenextrudethat,andyou’llhaveacube.
Circle:Again,thisoneisprettyobvious:youuseittomakecircles.Theycanbedefinedinanumberofways,suchasbyradius,diameter,centerpoint,tangentlines,andsoon.
Ellipse:Asyou’dexpect,thisisusedtodrawellipses.Youspecifytheheightandwidth
separatelyasneeded.
Arc:Bothcirclesandellipsescanbetrimmedtomakearcs,butyoucanskipthatextrastepanddrawanarcfromtheget-go.Justlikecirclesandellipses,arcscanbedefinedinanumberofdifferentwaysthatareusefulindifferentsituations(suchasbytheirendpointsandradii,threepoints,andtangencies).
Rectangle:Ifyoudon’twant
tobotherdrawingfourlinesmanually,youcanusethistoquicklycreatesquaresandrectangles.
Polygon:Tocreateapolygon(likeahexagonoroctagon),youcouldmanuallydrawit,butthatwouldtakeasignificantamountoftimetoproperlydefinetheanglesandlengthsofeachlinesegment.SomanyCADprogramsincludethis
commandtoquicklycreatepolygonswithaspecifiednumberofsides.
Text:Thetextcommandisusefulforengravingorembossinglettersontoafaceorforcreatingcut-outtext.
Fillet:Justlikeyoucanroundedgeswhenworkingwiththe3Dmodel,youcanalsoroundcornerswhensketching.Thecommandworksinthesamewaybydefiningaradius.
Chamfer:Youcanalsochamfercornerswhilesketching.Again,thisworksinthesamewayaswhenyou’reusingitonthe3Dmodel.
DEFINITIONA chamfer is a
simple beveled edge thatconnects two surfaces. If thesurfaces meet at 90degrees, a standard chamferwill cut across at 45 degreesfor symmetry. However, achamfer does not have to besymmetrical and can cutacross at other angles aswell.
Trim:Thiscommandisusedtotrimaline,circle,ellipse,andsoonbeforeorafteranintersection(orbetweentwointersections).Thisisanextremelyusefultool,asitallowsyoutocombineprimitiveoverlappingshapesintocomplexcross-sections.
Extend:Theoppositeofthetrimcommand.Thisextendsalinealongitscurrentpathuntilitintersectsanotherline.
Offset:Theoffsetcommandisusedtocreateanotherlinethatisoffsetfromanexistingline.Forexample,tocreateahollowtube,youcoulddrawacircleandoffsetitbythethicknessofthetubewall.Whenyouextrudethat,itwillcreateyourhollowtube.
Mirror:Thisisformirroringlinesacrossamirrorline.It’sverysimilartothemirrorfeatureusedinthe3D
modelingarea.
Pattern:HowexactlythepatternfeaturesworkdependsontheCADsoftwareyou’reusing,buttheyallhavethesamegoal.Itsjobistotakeapartofyoursketchandcreatecopiesofitinaspecifiedpattern.Thisisusefulforcreatingthingslikeventholes.
Dimension:Dimensioningyoursketchesisextremely
important.Ifyoursketchisn’tcompletelydefined,itcaneasilybeaccidentallydistorted.It’salsoessentialthatyouadddimensionseverywhereonyoursketchtomakesureit’sthecorrectsize.Howcanyoucreateatruecubeifyoudon’tensurethateverysidehasequaldimensions?
Constraints:Constraintsserveasimilarpurposeto
dimensions;they’reusedtokeepasketchdefinedexactlyasyouintend.Theycanbeusedtokeeplinesparallel,perpendicular,equalinlength,andsoon.SomeCADprogramsattempttoautomaticallycreateconstraints,whileothersrequirethatyouaddthemallmanually.Eitherway,it’simportanttomakesurethey’retherewhennecessary.
TheImportanceof Units andScaleBeforeyoustartmodelinganythingusingthecommandsI’vejusttaughtyou,it’sessentialthatyouunderstandtheconceptsofunitsand
scale.BothofthesearebasicfactorsinCADdesign,whichmakesthemcriticaltotheproperuseofyourCADsoftware.
Choosing UnitsThefirstthingyoushoulddowhenyoucreateanew3DmodelischooseyourunitssotheCADprogramknowswhatyouwant.Doyouwant
toworkininchesormillimeters?Poundsorkilograms?Forexample,whenyoutypein“1.25,”doesthatmean1.25mm,1.25cm,1¼inches,or1foot3inches?It’snotjustaquestionofwhetheryouwanttousethemetricsystemornot;rather,it’saboutthespecificunitsyou’llbeusingfordimensionsandforotherinformationlikevolumeandmass.
Theunitsyouuseforlengtharethemostimportantthingtospecifybyfar.That’sbecauseeverythingyoudimensionwhileyou’remodelingwillbeinlengthsandangles;whiletheanglesareuniversal,thelengthsarenot.
However,youcanalsochangetheunitsforvolume,weight,andeventime.Volumeandweightareuseful
fordeterminingthingsliketheweightandvolumeofthepart,densityofmaterials,andsoon.Timeisreallyonlyusedforsimulations,though,soyoushouldn’tworrytoomuchaboutit.
FASCINATING FACTThe proper use of units
will allow you to do a lot ofuseful things. For example,you can determine theweight of the part youdesign, its volume, and itscenter of gravity. This canhelp you figure out howmuch filament you’ll needand how the part willperform.
Sowhatunitsshouldyouuse?Ifyou’reAmerican,you’reprobablythemostcomfortablewithinches.However,thereisastrongcasetobemadeforusingmillimetersinstead.Firstofall,themathisjustaloteasierwhenyouusethemetricsystem.Fractionsofaninchcangetprettycumbersome,and12inchestoafootdoesn’tmakeforeasymath.
Butit’snotjustthemaththatmakesthemetricsystembetterforCADmodeling.Whenyouexportthemodelintothe.STLformatfor3Dprinting,theunitsyoumodeleditinaren’tsaved.Sotheyhavetobespecifiedbytheslicingsoftwarewhenyouimportthe.STL.Mostslicingsoftwareusesmillimetersbydefault,andmostpeopleexporttheirmodelsinmillimetersaswell.The.STL
filedoesn’tstorewhatkindofunitwasusedinitscreation,soit’snecessarytomakesuretheexportedunittypematchestheimportedunittype.
Whilethemodelcanbeconvertedtomillimeterswhenyouexportit,that’sjustaddinganotherstep.Personally,Ithinkit’sbesttousethemetricsystemfromthebeginningsoyou’re
comfortablewithit.However,ifyoureallywanttostickwithusinginches,youcertainlycan.
SpecifyingunitsinSolidworks.
Scaling in CAD
Onceuponatime,whenengineeringdrawingswerestillcreated\withapencilandpaperbydrafters,scalewasapracticalconcern.Ifyouwantedtodrawabuildingonapieceofpaperthatwouldfitinyourbriefcase,youobviouslycouldn’tdrawitatitsactualsize.That’swherescalecamein.
Inordertodrawsomethinglargeatapracticalsize,the
drafterwoulddrawitatafixedscale.Forabuilding,hemightdrawitatascaleof“⅛inch=1foot0inches,”meaningthatevery⅛inchonthepaperrepresented1footontheactualbuilding.Soawall10feetlongwouldbedrawnas1¼incheslongonpaper.Thedrafterhadtotakethisintoaccountwhilecreatingthedrawinginordertokeeptheentiredrawingatthecorrectscale.
However,withtheintroductionofCAD,thiswasnolongernecessary.In2DCAD,thedraftercoulddrawthebuildingatafull1:1scaleandsimplyrescaleitasneededforprinting.CADsoftwarecouldhandlerescalingthedrawingautomatically,sothedrafterwouldonlyeverhavetodrawthingsata1:1scaleandletthesoftwaredotherest.
Butsomehabitsdiehard.Forpeoplewholearneddraftingwithapencilandpaper,theideathatthingshadtobescaledtendedtostick.SomanypeoplecontinuedtocarryonwiththathabitandstilldrewthingsatdifferentscaleseveninCADprogramswhereitwasn’tnecessarytodoso.Thatcontinueseventothisday,despitethefactthatit’sentirelyunnecessary(andevencausesconfusion).
Evenmorebizarrely,thathabithasevenmanagedtomakeitswayinto3Dmodelinginsomecases.It’snotcommon,butsomepeoplestillmakethemistakeofdefiningthedimensionsatascaleotherthan1:1.It’simportantthatyoulearnfromtheverybeginningnottodothis,becauseit’llcausealotofheadachesifyoudo.
Whenyou’reusingCAD
software,alwayscreatedimensionsata1:1scale.Ifsomethingissupposedtobe100mmlong,giveitadimensionof100mm.Thisshouldn’tbehardtodo,becauseit’sthenaturalthingtodoanywayifyou’renewtoCADanddrafting.
Ifforsomereasonyouneedtocreateadrawingandthemodeldoesn’tfitonthepageat1:1(orit’stoosmall),scale
thedrawingitselfinsteadofthemodel.Ifyouwantto3Dprintaminiatureversionofsomethingyoumodeled,youcanscaleitinslicingsoftware(unlessit’sintendedtoalwaysbeminiature).Basically,thebestwaytoapproachthisistojustnotthinkaboutitanddimensioneverythingatitsactualsize.
The Least You
Need to KnowCADsoftwareisdesignedforcreatingmodelswithspecificdimensions,whileartistic3Dmodelingsoftwareisusefulforsculptingfree-formmodels.
SpecificCADcommandsdependonthesoftwareyou’reusing,butmosthavesimilarsetsofcommands.
Unitsareimportant,andmyrecommendationistousethe
metricsystem,becauseit’swhatthe3Dprintingcommunitytendstouse.
AlwayscreateallCADdimensionsata1:1scale.Ifanyscalingneedstobedone,itshouldbedoneseparatelyinthedrawingortheslicingsoftware.
CHAPTER
16
ModelingTechniques
andBest Practices
In This Chapter
Designingassemblies
Tipsforsuccessful3Dmodeling
Howtocreatemodelsfor3Dprinting
JustknowingtheCADcommandsisn’tenoughifyouwanttohaveanenjoyable3Dmodelingexperience.It’salso
importanttogetagoodgraspoftheworkflowusedbyCADdesigners.Withagoodworkflow,you’llbeabletodesignanythingwithenoughpatience.Everyonehastheirownmodelingstyle,andyou’lldevelopyourown.Butwiththischapter,Igiveyouagoodstartingpointtogetyouonyourway.
PremodelingBeforeyouactuallystartmodelinganything,youwanttohaveagoodpictureinyourmindofwhatitisyouwanttomodel.Youcan’tjuststartmodelingifyoudon’thaveaclearideaofwhatthefinishedobjectshouldlooklike.(Well,technicallyIsupposeyoucould,butitwouldbeafrustratingexperience.)In
fact,it’snotuncommontospendmoretimethinkingaboutwhatyou’regoingtomodelthanactuallymodelingit.
Takeyourtimewiththisprocess,anddon’tjustjumprightintothemodeling.Ifyoustartbeforeyou’reready,youcouldeasilyspendmoretimefixingthemodelthanifyouhadjustbeenpatientanddoneitrightfromthe
beginning.
Onceyou’vecomeupwithaclearideaofwhatyou’regoingtomodel,it’stimetoopenyourCADprogramandgetstarted.Thereareamillionwaystomodeltheexactsamepart,andhowyougoaboutmodelingitispartofyourstyle.Everyonewilltakedifferentapproachestothesamemodel,andthereisn’tnecessarilyanyright
way.
Thatsaid,therearesomebasictechniqueswhichmostpeopleuse.Theideaistostartwithlargefeaturestocreatearoughshape,andthenaddfeaturestorefineit.Asyou’remodelingthosefeatures,besuretoadddimensionsandconstraintstofullydefinethesketchesyoucreate.
Inordertoaddthose
dimensions,youshouldalreadyhaveanideaofwhattheyshouldbebeforeyoustartmodeling.That’spartofthepremodelingthoughtprocessandhelpstospeeduptheactualmodeling.
Tricks of theTrade
WhenI’mnotwritingdelightfulbookson3Dprintingforyoutoread,Iworkasamechanicaldesigneranddrafter.Thismeansmyjobistodo3DCADmodelingandtocreatetechnicaldrawings.Inmytimedoingthis,I’vepickedupafewtrickstomakethemodelingprocessmoreefficient,andI’mgoingtoteachthemtoyou!
HOT TIPTo determine if a
particular feature isessential, ask yourself if thepart could still functionwithout it. In most cases, aparticular part will only havea handful of essentialfeatures. The rest are reallyonly there to improve theaesthetic and feel of thepart.
Separatetheessentialfeaturesfromthosethataremostlyjustcosmetic.Startwithgettingthefunctionalityofthemodelrightbeforeyoustartinwiththosefeaturesthatarereallyjusttheretomakethepartlookfinished.Thingslikefilletsandchamfersareusuallyjustaddedtomakeedgeslesssharp,sosavethoseforlast.Ontheotherhand,thingslikeboltholesandmating
surfacesareessentialtothefunctionalityofthepart,soconcentrateongettingthoserightfirst.
Ifyoucan,trytoprioritizethefeaturesbasedonhow“hard”theyare.Bythat,Imeanfeaturesthathavestrictrequirementsshouldcomefirst.If,forexample,you’redesigningareplacementbracketforashelf,you’llwanttomodelthescrew
holesassoonaspossibletomakesurethey’reright.Afterthat’sdone,youcanmoveontoaddingthingslikesupports,andthenfinishingtoucheslikefillets.
Startwithimportantfeatures,likemountingholes.
Getcomfortablewiththecommandsthataredesigned
tospeedupthemodelingprocess.Ifyourpartisgoingtobesymmetrical,thereisnosenseinmodelingtheentirething.Instead,justmodelonehalfandthenmirrorthefeaturestotheotherside.Thathastheaddedbenefitofensuringthatbothsidesareexactlythesameandreducesthechancesofmakingasimplemistake(likeenteringthewrongdimension).
ThepatterntoolsincludedinmostCADprogramscanalsobeveryhelpfulinthisregard.Ifidenticalfeatures(likeholesorslots)willbeusedinregularintervals,that’stheperfectsituationtotakeadvantageofthepatterntool.Thisisn’tjustforlinearorrectangularpatternseither;mostCADsoftwarehastheabilitytocreatecircularpatterns,whichisgreatformodelingthingslikegear
teeth.
Inordertotakeadvantageofallofthesetools,youshouldtakethetimetoexploreyourCADsoftwareeverynowandthen.MostCADdesignerstendtogetcomfortablewithcertaintoolsandwilloftenusethoseevenwhenanothertoolwouldworkbetter.Sodon’tbeafraidtoexperimentwithdifferentcommands,soyou’llbefamiliarwiththem
whentherightsituationarises.
Keepthingssimple.It’sbettertousetwosimplefeaturesthanonecomplexfeature.Doingsowillmakeerrorslesslikelyandwillmakethefeatureseasiertomodifylaterifneeded.Ifyoueversharethemodel,it’llalsomakeiteasierforotherpeopletofollowyourwork.
Ifyouhaveanyexperience
withprogramming,you’llprobablyrecognizetheimportanceofthis.Complexformulasandstatementsmaytakeuplessspace,butthey’realsodifficulttodecipherandmodify.Thefeaturesina3Dmodelcanbesimilar.Youcoulddrawareallycomplexsketchtodoasmuchaspossibleinasinglefeature,buttherereallyisn’tanybenefitindoingthat.Instead,youcouldjustbreakitupinto
afewsimplesketchesthatwillbeeasytounderstandandmodifylater.
You’llprobablyneedtomodifyyourmodel.Relatingtomy“keepthingssimple”tip,it’sraretogetthemodelexactlyrightonyourfirsttry.Thechancesaregoodthatyou’llneedtochangesomedimensionsattheveryleast,andpossiblyremodelsomethingscompletely.
Tobeabletomakethosemodificationswithoutalotoftrouble,you’llwanttousegoodtechniquewhilemodeling.Setupallofyourconstraintsproperlyanddefineallofyourdimensions.Don’tgetsloppy,becauseyou’lljustbemakingitharderonyourselfwhenyouhavetomodifythemodellater.CADmodelingisn’tarace;takeyourtimetodoitright,andyou’llsaveyourself
sometroublelater.
Sometimesit’sbesttojuststartoverfromscratch.Thistipmaybethehardesttoswallow.Ifyou’vespentalotoftimemodelingsomething,itcanbedifficulttojustgiveuponit,butthat’softenthebestchoice.AsI’vementioned,thereareamillionwaystomodelsomething.Youmaynotrealizeuntilyou’refinishedthatyou
chosethewrongwaytomodelaparticularpart;ithappenstoallofus.
Ifyoumodeledthepartinawaythatislessthanideal,itcanbedifficulttomakeadjustments.Tryingtomakeadjustmentstoabadmodelwilloftentakemoretimethansimplyremodelingtheentirething.Oneofthebestskillsyoucanlearnishowtoknowwhentojuststartoverwitha
cleanslate.
Assembliesand FittingPartsModelingasinglestandalonepartisusuallyarelativelysimplematter.Butthingsgetsignificantlymore
complicatedwhenyoudesignassemblies.Anassemblyissimplyagroupofpartsthataredesignedtofittogether.Forexample,acarengineisanassembly.And,technicallyspeaking,thecaritselfisanassembly,too.
Butthetermsaren’treallyimportant.What’simportantistheideathatassembliesaresystemsofpartsthataredesignedtofittogether.
Asanexample,picturearegularoldpairofscissors.Thinkoftheall-metalkind,notthekindwithplastichandles.Apairofscissorslikethatisaverysimplethree-partassembly,madeupofonebladeandhandle,thesecondbladeandhandle,andtherivetholdingthemtogether.Butevenasimpleassemblylikethattakessomeplanning.
Eachbladeandhandlehastobedesignedasyou’dexpect:tohaveasharpenededgeandcomfortablehandle.Butitalsohastobedesignedtofitwiththeotherpiecetomakeafunctionalpairofscissors.Thatmeansthebladeshavetobedesignedtolineupproperly,atthesametimethatthetwohandlestouch.
Asyouaddmorepartstoanassembly,thingsget
exponentiallymorecomplicated.Amechanicalwristwatch,forexample,isoneofthemostcomplexmechanicalassemblieseverdevised.Thereareabunchofpartsthatallhavetofittogetherperfectlyinaverysmallspace.Designingsomethinglikethatismind-bogglinglydifficult,becausetherearejustsomanyinterfacingpartstoplan.
FASCINATING FACTAs complicated as
mechanical wrist watchesare, they’re even moreimpressive when youconsider the times in whichthey were designed. Theparts and assemblies wereall sketched with a penciland paper, and the partswere mostly made with basichand tools. Even with ourmodern software and tools,replicating a mechanism thatcomplicated is very difficult.
Asyoucansee,designingassembliesisnoeasytask;I’mnottalkingaboutjustputtingLegostogether.Eachparthastobedesignedtoperformitsfunction,andalsotoconnectwiththeotherpartsintheassembly.
Planning an
AssemblySohowshouldyougoaboutdesigninganassemblywithmultiplepartsthatneedtofittogether?Theansweriscarefulplanning,andunfortunatelythereisnoquickandeasytricktothis.Thisiswhatmechanicalengineersanddesignersarepaidtofigureout,sodon’tletitbotheryouifyoufindtheprocessdifficult.
Thisplanningstageisoneareawhere2DCADprogramscancomeinhandy,eveniftheactualpartswillbemodeledin3D.Youcandrawoutarepresentationofthepartsintheassemblytogetanideaofthedimensionsoftheindividualparts.
Toillustratethis,imagineyouhada100mm-longbeltandtwopulleyswithdiametersof10mm.Youwantto
determinehowfarapartthepulleysneedtobemountedinordertokeepthebelttaut.
Tryingtofigurethisoutwhilemodelingthepartswouldbefairlydifficult,butyoucandoitquicklyandeasilyin2DCAD.Youcandrawonepulleyasacircle,withanotherhalf-circlearoundittorepresentthatpartofthebelt.Youcanthenmeasurethelengthofthathalf-circle
(inthiscase,16.4934mm).Weknowthattherearetwopulleys,soyoumultiplythatby2andget32.9868mm.Subtractthatfrom100mm,andyouget67.0132mm,whichistherestofthebelt.Dividethatby2,andyouget33.5066mm.
Sketchingin2Dtocomeupwithdimensionsformodelingabeltand
pulleysystem.
HOT TIPIf the pulley example is
a little difficult to wrap yourhead around, try thinkingabout why it works. The beltis wrapping around twopulleys, so it will be incontact with half of eachone. So you take half of theperimeter of each pulley and
add that. You know the beltis 100mm, so you subtractthe perimeters from that.You then divide the result by2 in order to get the distancebetween the pulleys (sincethe belt is a loop). Drawingthis just saves you fromhaving to do the mathmanually.
Soyounowknowthepulleysneedtobemountedabout33.5mmapartinorderto
keepthat100mm-longbelttaut.Withthatinformation,youcandesignyourassemblyknowingexactlywhereyourpulleysneedtobemounted.Thisremovestheguessworkfromtheprocess,whichiskeytosuccessfullydesigningassemblies.
Thisillustration,ofcourse,isaverysimpleexampleofthekindofthingyou’llneedtoplanfor.Intherealworld,
assembliesareusuallymuchmorecomplicated.That’swhyyou’llneedtotakethetimetocarefullyplanouttheassemblybeforeyoustartmodelingit.
Fitting PartsTogetherButwhataboutjustdesigningtwopartsthatneedtofittogether?Anytimeyoudesign
anassembly,you’llhavetothinkabouthowyou’reactuallygoingtoconnectthevariouspartstoeachother.Areyoujustgoingtoboltthemtogether?Doyouwanttodesignsomekindofclipsystem?Whataboutpartsthatneedtofittogetherlikepuzzlepieces?Youcangenerallybreakthisdownintotwobasictypes:partsthatwillbefastenedtogetherandpartsthatneedto
fittogether.Fasteningpartstogetherisactuallyasurprisinglycomplicatedtopic.Takeastrollthroughthefasteneraisleatyourlocalhardwarestoreandjustlookathowmanydifferentkindsofscrews,bolts,nuts,clips,nails,andsoonthereare.Thereasontherearesomanytypesoffastenersoutthereisbecausethereareallkindsof
differentrequirementswhenitcomestoputtingpartstogether.
Butforourpurposesit’sbesttokeepitassimpleaspossible.Herearesomedifferentwaystofitpartstogether:
Ifyou’rejustattachingtwopartstogetherandtherewon’tbealotofstress,youcanjustuseundersizedholesandscrewsomemachine
screwsintothem.Becausetheplasticisrelativelysoft,itwillbasicallyjustcutitsownthreads.
Ifyourassemblyrequiresabitmorestrength,youcanuseheatsetinserts.Thesearelittlemetaltubeswiththreadsontheinsideandridgesontheoutside.Youheatthemupandpushthemintoaholeintheplastic.Asyoupushitin,itwillmelttheplasticaroundtheinsert,andthenitwillcooltolocktheinsertin.
You’llthenhavesomenicemetalthreadsforyourscrews.
It’spossibletoavoidusingscrewsaltogetherinsomesituations.ThebatterycoveronthebackofyourTV’sremotecontrolisagoodexampleofthis.Insteadofscrewingthebatterycoverontothebodyoftheremote,asmall,springytabisusedtoholditinplace.Youcandesignsimilartabstoholdyour3D-printedparts
together.
FASCINATING FACTThere are many such
techniques like the springytab that can be used toconnect parts togetherwithout having to usefasteners. Woodworking isfull of these ingeniousjoinery methods that don’tuse fasteners, so that maybe one area you can lookinto for inspiration. You can
also just look at the productsaround your home for ideas.You may be surprised byhow many techniques havebeen developed over theyears.
Fittingpartstogetherwithoutfastenersisawholeotherskill.It’sonethingtosimplybolttwopiecesofwoodtogether,whileit’ssomethingelseentirelytojointhem
togetherwithsomethinglikeatongueandgroove.Whenitcomesto3Dprinting,howpartsactuallyfittogethercanbealittlefrustrating.Sayyouwantedoneparttofitinsideother,likeapistoninacylinder.Togetatightfit,thepistonhastobejustslightlysmallerthantheinnerdiameterofthecylinder.Thequestionis:howmuchsmaller?
Thatquestionisamajoroneintheengineeringworld,anditreallydependsonwhatyou’retryingtoaccomplish.Ifthepartswillbemoving(likeapiston),itcan’tbetootightorthefrictioncanbeaproblem.Ontheotherhand,ifthepartsaren’tsupposedtomove(likeadowelpin),itneedstobeverytight.
But3Dprintingthrowsinanothercurveball.Because
thetolerancesinvolvedwithFFF3Dprintingaresoloose(easily+/-0.1mm,butoftenmuchmore),it’shardtogetaprecisefit.Soyou’llneedtodosomeexperimentingtodeterminehowmuchofagaptoleavebetweenpartsfordifferentapplications.Thiswilldependonyourprinter,thetypeoffityou’retryingtoget,andevenontheparticularpartyou’reprinting.
ModelingSuccessful3D PartsWhenyou’remodelingpartsfor3Dprinting,thereareafewthingsyoushoulddotoensuretheycanbeprintedsuccessfully:
Avoidsupports,ifpossible.Youcanreallydesignthepart
howeveryouwant,ifyouplanonusingsupports.Butideally,you’dwanttodesignthepartsoyoucanprintitwithoutsupports.Printingwithoutsupportsgenerallyyieldshigher-qualityparts.
Makesurethepartisn’ttoobigforyourprinter.Thatincludesanythingthat’saddedintheprintingprocess,likerafts,brims,orsupports.Thosecaneasilyadd10mm
toallsidesofthepart,sotakethatintoaccountwhendesigningthepart.Ifit’satightsqueeze,youmaynotbeabletousebrimsorrafts,whichcouldaffecthowwellthepartprints.
Takestepstolimitwarping.Warpingcanbeaverydifficultproblemtoovercome,anditgetsworseasthepartgetslarger.That’sbecausewarpingiscausedby
thecontractionoftheplasticasitcools.Thelongerandtallerthepartis,themorematerialthereiscontractingandthemorewarpingthereis.
Slotswereaddedtothiselectronicsenclosureforventilationandto
limitwarping.
Thereissomethingyoucandotolimitthatwarping,though.Becausewarpingiscausedbythecontractionin
longpiecesofplastic,youcanfightthewarpingbyinterruptingthoselong,solidpiecesofplasticwithholesorslots.Theideaisjusttobreakupanylong,solidstretches,sothecontractiononlyoccursinshortareastoreducetheeffect.Ofcourse,that’snotalwayspossible.Ifthat’sthecase,youmayhavetouseamaterialthatislessproneto
warping(inotherwords,materialsthatdon’tcontractasmuch).PLAisagoodoption,becauseit’ssignificantlylesssusceptibletowarpingthanABS.
HOT TIPThese challenges can
sometimes be difficult toovercome, but it shouldn’ttake long for it to becomesecond nature. Compared toother manufacturingprocesses, 3D printingactually has very few designconstraints. Just keep inmind how the design of yourpart will be printed.
ExportingFilesOnceyou’vefinishedmodelingyourpart,you’llneedtoexportitfor3Dprinting.Asyou’velearnedinpreviouschapters,youneeda.STLfilefortheslicingsoftwaretoworkwith.Luckily,allCADsoftwarecaneasilyexportmodelsinto
the.STLformat.
Whenyouexportthemodel,youwillthenneedtospecifyafewthingsforthe.STLfile.Thefirstthingyou’llneedtosetistheunits.I’vementionedpreviouslythat.STLfilesdonotstoreunitinformation,sothathastobesetwhenyouexportthefilefromtheCADprogramandwhenyouimportitintotheslicingsoftware.The
exportedandimportedunitshavetomatch.Mostslicingsoftwareusesmillimetersbydefault,soyoushouldexportthefileinmillimeters(unlessyouhaveareasonnotto).
You’llalsoneedtospecifythequalityyouwantinthe.STLfile.Thisessentiallydetermineshowmanytriangleswillbeusedtomakethesurfacesofthemodels.Moretrianglesmeanhigher-
qualitysurfaces.Thisisespeciallyapparentwithmodelsthathavecurvedsurfaces.
The.STLexportsettingsinSolidworks,includingtheoptionstosettheresolution(forthequality
ofthemodel).
Ifamodelwithcurvedsurfacesisexportedwithalownumberoftriangles(resultinginasmallfilesize),thosecurvedsurfacescouldcomeoutlookingfaceted.Insteadofanice,gracefulcurve,you’llhaveaseriesofflatsegmentsmakingupthecurve.
Inordertomakesureyourprintedpartscomeoutatthehighestqualitypossible,I
recommendyouturnthequalitysettingsallthewayupwhenyouexportthe.STLfile.Thismightcreatean.STLfilethatisverylarge.So,ifyou’replanningonsharingthefileonline,youmayneedtoturnthequalitydown.Otherwise,thereisnorealreasonnottousehigh-qualitysettingsonamoderncomputer.
The Least YouNeed to Know
Alwaysplanyourmodeloutaheadoftime,especiallyifyou’remodelinganassembly.
Sometimesit’sbettertojuststartoverthantotryandsalvageabadmodel.
3Dprintinghassomeuniqueconsiderationswhenitcomestomodeling.Thisis
especiallytruewhenitcomestoreducingwarping,whichhappenswhenthematerialcontractsasitcools.
CHAPTER
17
PracticalReverse
Engineering
In This Chapter
Whyyou’llwanttolearnreverseengineering
Measurementtoolsthatareusefulandaffordable
Techniquesfordeterminingpartdimensions
Thetwowaysyoucanmodelapart
Inthecontextof3Dprinting,reverseengineeringisthe
practiceofduplicatingthedesignofapartorassembly.It’seasytoseewhythisisausefulskilltolearnforthe3Dprintingenthusiast.Ifyouwanttoreproduceapartorinterfacewithanexistingpart,you’llneedtoknowhowtoreverseengineerit.
Luckily,reverseengineeringsimplepartsprobablyisn’tquiteasdifficultasyou’reexpecting.It’sarelatively
simpleprocessoftakingmeasurementsand3Dmodelingthepartbasedonthat.However,actuallytakingaccuratemeasurementscanbealittletrickyinsomecases,soI’vegivenyousomehelpfultipsandhintsinthischaptertohelpyouout.
Why You
Should LearnBasicReverse EngineeringOneusefor3Dprintingthatmanypeopleareinterestedinistheabilitytoreplacebrokenpartstheycomeacross.Brokenshelfbrackets,carparts,andreallyanythingmadeofplasticcanbe
replacedwitha3D-printedpart.Spending50¢onfilamentissurebetterthanbuyingoverpricedreplacementpartsfromthemanufacturer(ifthey’reevenavailable).
Insomecases,youmaybeabletofindsomeofthosepartsonlinethatsomeoneelsemodeled.Butmostlikely,themajorityofthethingsyou’llwanttoreplacehaven’tbeen
modeledyet.Forthatreason,you’llneedtolearnhowtodoityourself.
Reverseengineeringapartmaysoundabitoverwhelming,butit’snotasbadasitsounds.Allyou’llbedoingis3Dmodelingapartascloselytotheoriginalaspossible.You’lljustbetakingmeasurementsandmakingsuretheimportantmeasurementsareasaccurate
aspossible.
DEFINITIONReverse
engineering, in a generalsense, is the process ofdetermining the functionand/or design of a man-made object or system. Thiscan be anything fromreverse engineeringsoftware to complicatedmechanical systems.
Sowhichmeasurementsaretheimportantones?They’retheonesforthingslikescrewandboltholes,theoverallshapeandsizeofthepart,andanyfunctionalfeatures.Formostthingsyou’llprobablywanttoreplace,therewillprobablyonlybeafewfeaturesthathavetobeexact.Thismeansthereisalmostalwayssomeroomforinaccuracyontheunimportantfeatures.
Finding theRightMeasurementToolsThereareawiderangeoftoolsusedtomeasurepartsforreverseengineering.Professionalengineersusesomeexpensivetoolslike
comparators,go/nogogauges,orthreadgauges.Theseareprecisiontools(withthegaugesneedingtobeboughtinsets)andareusuallyquiteexpensive.Inaprofessionalenvironment,theyalsoneedtoberegularlycheckedtoensurethattheyarewithinspec.Luckilyforhobbyists,though,mostofthosearen’tnecessaryforthekindofreverseengineeringyou’dbedoingathome.
Thefollowingdescribethetwomostcommonlyusedmeasurementtoolsbyhobbyists;asyou’lllearn,oneisanecessityformeasuring,whiletheotherisoneyoushouldprobablystayawayfrom.
Digital Calipers: ANecessary ToolCalipersareasimple
measurementtoolthatmeasurethedistancebetweenthearmsoftheslide.Evenintheprofessionalworld,digitalcalipersarewhatengineersusemostofthetime.They’reasurprisinglyversatileinstrument.Digitalcaliperscanbeusedtomeasureinteriordistances,exteriordistances,andusuallydepthsaswell.Withsimpledistancemeasurements,mostothermeasurements(likeangles
andradii)canbededuced.
Averyinexpensivepairofdigitalcalipers.
Thesedays,simpledigitalcaliperscanbepurchasedforlessthan$20.Evenatthatprice,they’restillreasonably
accurate.Theaccuracyofdigitalcalipersisusuallywithin0.02mm,whichisbetterthanmost3Dprintersarecapableofanyway.
HOT TIPDon’t bother spending
a lot of money on your firstpair of digital calipers. High-end digital calipers can bepretty pricey and areunnecessary for hobbytasks. Inexpensive caliperswill do just fine for mostpeople outside of aprofessional engineeringenvironment.
3D Scanners: NotAll They’reCracked Up to BeIfyou’vebeeninvestigating3Dprinters,youmayhavealsocomeacross3Dscanners.3Dscannersaredevicesthatopticallymeasurethousandsofpointsonthesurfaceofanobject.Withthosepointsmeasured,a
computercanreconstructthesurfaceofa3Dobject.
Theideaisthatyoucanjustthrowapartonthe3Dscanner,scanit,andthenprintaperfectcopy.Theappealofthisisprettyobvious;ittakesawayallofthetroubleofhavingtoreverseengineerapart.Butdo3Dscannersfulfilltheirpurpose?
Theshortanswer,
unfortunately,isno.Thisisfortwobigreasons:theaccuracyofthescanandtheusabilityoftheresultingmodel.Bothoftheseareaprettybigdealandarekeeping3Dscannersfrombeingparticularlyusefulinengineeringapplications.
Theaccuracyissueisonewhichyoucanprobablyseetheproblemwithprettyeasily.Evenhigh-quality
scannerstendtoresultinimperfectmodels.That’sespeciallytrueforcomplicatedpartsorpartswithanyinternalgeometry.
Because3Dscannersworkoptically,theycanonlyscanwhattheycansee.Ifthereisanyinternalgeometry,thescannerwouldn’tbeabletoseeit.Sothatgeometrywouldn’tbereplicatedandwouldbelost.
FASCINATING FACTTinkerers, hackers, and
makers have beenexperimenting with thedevelopment of inexpensive3D scanners for a whilenow. Prototypes have beenmade from the MicrosoftKinect and even as apps oncell phones. However, noneof these are at the point yetwhere they’re very useful forreverse engineering.
Thatleadsustothebiggerissue:thecreatedgeometrycan’tbeeasilymodified.Thescanjustproduceswhatisessentiallyasurfacemesh.Noactualfeaturesarecreated,whichmeanstherearenofeaturesforyoutomodify.
Ifyouwanttomodifythemodelgeneratedbythe3Dscanner,you’llhavetomodifythemesh.Thesameis
trueifyoujustwanttofixthemodel,likeaddinginternalgeometryorfixingerrors.Tomodifythemesh,you’llhavetousethoseartistic3DmodelingprogramsItalkedaboutbefore.
Measuringthe Part
Forsomeparts,measuringwillbeasimpleprocess.Forothers,itcanbesignificantlymorecomplicated.
Let’sstartwithaverysimplepart,likeacube10mmtoaside.Tomeasurethatpart,youjustcloseyourcalipersandsetthemtozero.Youthenjustmeasurethedistancebetweenthreesetsofperpendicularfaces.Ifitwasaperfectcube,you’dget
exactly10mmbetweeneachsetoffaces.And,ofcourse,tomodelthatpartyou’djustmakeacubethatis10mmineachdirection.
Makesuretosetyourcaliperstozerobeforemeasuring.
However,asyoumightimagine,mostpartsaremuchmorecomplicatedthanacube.Tomeasurerealparts,
you’llhavetomeasurethedistancebetweenalotmorepoints.Butthebasicprincipleremainsthesame:gathermeasurementsandreproducetheminyourmodel.
Doingthiswilltakeadecentunderstandingofgeometry.Inmostcases,youprobablywon’tphysicallybeabletotakemeasurementsofeveryfeatureonthepart.Somewon’tbereachable,while
otherswillhavecurvesorangleswithcan’tbemeasured.Thatbringsmetothemostimportantreverseengineeringskillyouneedtolearn:howmakeinferences.
InferencesWhencalipersareyouronlymeasurementtool,you’vegottolearnhowtomakesome
inferencesaboutthepart.Theinferencesyou’llneedtomakecanbebrokendownintoroughlythreetypes:geometric,designintention,andproportions.Formostparts,you’llneedtouseallthreetoreallygetthepartmodeledright.
GeometricTheeasiestkindofinference
youcanmakeisgeometric.Ifyoucanrememberyourhighschoolmathclasses,thesearethetypesofproblemswhereyou’regiventwovariablesandhavetofindthethird.They’rebasedonunderstandingthemathematicsofgeometry.
Lengthsanddistancescanbeeasilymeasuredwiththedigitalcalipers,soyou’llusuallybetryingtouse
geometricinferencestofigureoutanglesandradii.Doingthatmightseemoverwhelmingatfirst,butrememberthatyourCADsoftwarecanhelpyoudomostoftheactualmath.Youcanjustdrawlineswiththeinformationyouknow,andthenletthesoftwarefillintherest.
Anexampleofmakingageometricinferenceaboutan
angleisabasicrighttriangle.Youdon’thavetoknowtheangleofthehypotenuse;youjusthavetoknowthelengthoftwosides(sinceyouknowthatoneangleis90°).Inthecaseofthefollowingimage,thetwosideswere10,andthesoftwarefilledinthehypotenuseof14.1421.IfyouusethePythagoreantheorem—wherea2+b2=c2(withcbeingthehypotenuse)—to
checkthis,you’llfindthisiscorrect.Similarinferencescanbemadeaboutisoscelestriangles,whichhavetwosidesofequallength,ifyouknowthelengthsofallthreesidesortwosidesandtheheight.
DEFINITIONThe hypotenuse of
a right-angled triangle is thelongest side of the triangle.It’ll always be the sidewhose endpoint doesn’ttouch the right angle.
Ofcourse,youwon’tjustbemeasuringtriangles.However,thegoodnewsisthatmostfeatureswithanglescanbebrokendowninto
simpleshapesliketriangles.
Twosidesofthisrighttrianglewereenteredmanually,andthe
hypotenusewasthendeterminedbytheCADsoftware.
Design IntentionInmyhumbleopinion,designintentisthesinglemostimportantclueyouhavewhenitcomestoreverseengineering.Theprinciplebehindthisissimple:everypartwasdesignedbyanotherperson.Peopletendtodesignpartsinfairlypredictableways,soyoucanmakeassumptionsaboutthepartbasedonthat.
Remembertheprevious10mmcubeexample?Let’simaginethatinsteadofmeasuringexactly10mmforeachpairoffaces,youactuallymeasured9.89mm,10.01mm,and10.8mm.Youcouldmodeltheparttothoseexactdimensions.Oryoucouldaskyourselfaboutthedesigner’sintentionswhenhecreatedthepart.
Isthereanyreasonwhyhe
wouldhavegivenitthoseexactdimensions?Ifnot,isitmorelikelythatitwasintendedtobe10×10×10mm?Maybethedifferencesareactuallyasimpleresultofpoortolerancesinmanufacturing.
Acaseoffiguringdesignintention.Themeasurementwas11.9mm,butwecanprettysafelyassumeitwas
intendedtobe12mm.
Unfortunately,it’snotquitethatsimple.Thistime,let’ssaythemeasurementswere9.52mm,9.53mm,and9.51mm.Youmightchalkthatuptopoormanufacturing.Butinreality,thedesignermighthavebeenworkingininches.⅜inchequals9.525mm,sothedesignermighthaveintendedittobeexactly⅜inch.
Ibetthisisstartingtosound
likeaprettybigheadache,right?Howcanyoupossiblyfigurethisoutwhentherearesomanyfactors?Oneoftheeasiestwaysistofirstdeterminetheoriginofthepart.
IfitwasdesignedanywherebutintheUnitedStates,itwasprobablydesignedinmillimeters.IfitwasdesignedintheUnitedStates,itreallycouldgoeitherway.
Someindustries,especiallyolderonesliketheconstructionandautomotiveindustries,tendtosticktousinginches.Somenewerindustries,likethetechindustry,oftenusemillimetersinstead.Thismaynothelpyoudetermineforsurewhatunitswereusedtodesignthepart,butitshouldhelp.
Linearmeasurementsaren’t
theonlythingthatcanbedeterminedbasedondesignintent,though.Youcanusetakethatintoaccountforeveryfeatureonapart,includingcurves.Doesananglelooklikeit’sabout45°?Thereisaverygoodchanceitis.Ifaradiusseemstomeasureouttoabout3mm,youcanprettysafelyassumethatwashowitwasdesigned.
Thewholeideabehindthis
techniqueisthatyoutryandthinkliketheoriginaldesignerofthepart.Ifyouweredesigningthatpart,wouldyouchoosesomeoddnumber?Probablynot;you’dmostlikelychooseanice,roundnumberunlessyouhadnootherchoice.Youcanusethatfacttoyouradvantagewhentryingtodeterminehowyoushouldmodelthepart.
ProportionsAndfinally,youcanmakeproportionalinferences.Thesearejudgmentsyoucanmakejustbyeyeballingthepart.Togobacktothe10mmcubeagain,wouldyoureallyneedtotakeallofthemeasurementstoknowitisacube?Youcouldprobablyjusttakeone10mmmeasurement,andthennoticeitwasacubeandderivethe
othermeasurementsfromthat.
Asusual,though,mostpartsaren’tcubesandwon’tbethissimple.Instead,you’llbelookingattheproportionsoftheparttohelpdeterminethemeasurements.Ifthereisarectangularshapeandyouknowthatonesideis10mmandtheothersidelookstobeabouttwiceaslong,youcanprettysafelyassumeit’s
about20mm.
Evenifyoucanonlydetermineonemeasurement,it’seasytoreasonablyinfertheother
dimension.
That’sbecauseashumans(youarehuman,right?),
we’reprettyterribleatestimatinglengthsanddistances.Butwe’resurprisinglygoodatmakingcomparisons,liketheproportionsbetweenfeatures.I’mnotsureexactlywhythisis,butit’strue.
Whateverthereason,it’struethathumansaremuchbetteratjudgingproportionsthantheyareatjudgingactualmeasurements.Sousethatto
youradvantagewhenmodelingparts.Don’ttrytoguessallofthemeasurements;justguessproportionsbasedonknownmeasurements.
Butwhywouldyouevenneedtobeguessingatall?Ifyouhavethosenicedigitalcalipers,whyevenbothertryingtoguessproportions?Themostcommonreasoniswhenyou’retryingtomodel
apartthatyoudon’tphysicallyhaveaccessto,likeifyou’rereproducingapartfromaphoto.Youmightbeabletodeducesomeofthemeasurementsfromotherobjectsinthephoto,oryoumightbeabletofindsomemeasurementsonlinethatotherpeoplehavetaken.Ifthat’sthecase,youcanusetheproportionsoftheparttodeterminethemissingmeasurements.
Youcanalsousethistechniqueforfiguringoutdimensionsinareasyoucan’tmeasure.Thisisespeciallytrueforinteriorfeaturesthatjustaren’taccessible.Unlessyouwanttotryandcutthepartinhalf,you’llneedtomakesomeinferencestogetthosemeasurements.
Modeling the
PartYou’velearnedallofthesemethodsfordeterminingthedimensionsofapartyouwanttoreplicate,sonowit’stimetomodelit.Therearetwowaysyoucanapproachthis:modelitasyoumeasureit,ortakeallofyourmeasurementsaheadoftimeandthenmodelit.Whichapproachyoutakeismostlyjustamatterof
personalpreference.
Personally,ItendtomodelthepartatthesametimeItakethemeasurements.Themainreasonisthatit’seasierthanhavingtotryandwritethemeasurementsdowninasensibleway.Ithinkitalsosavesalittletimeintheprocess.
Butwritingdownthedimensionscanalsoworkwell.Thatwayyoudon’t
havetokeepswitchingbackandforthbetweenmodelingandmeasuring.Youcanjusttakeallofyourmeasurementsandthenswitchtomodeling.
HOT TIPWhen writing down
dimensions, you’ll alwayswant some method forkeeping them in order. Youcan do this by sketching aquick drawing of the partand writing in the
dimensions. Or if drawingisn’t your cup of tea, you canassign descriptions to thedimensions. But dosomething to keep themorganized, so you don’taccidentally get them mixedup.
Modelingapartwhenyouonlyhavedigitalcalipersformeasurementscanbealittletricky.AsIwentoverinthe
previoussections,thereareoftenalotofmeasurementsthatcan’tbetakenwithcalipers.Sothisiswhenyou’llwanttostartusingthetechniquesyoujustlearned.
Startbydoingasmuchasyoucanwiththemeasurementsyouwereabletotake.Thesewillbeyour“hard”dimensions,whichyoucanbereasonablysureabout.Makeinferencesaboutthedesign
intenthere,likeusingroundnumbersunlessitmakessensenotto.
Onceyou’vegotallofthoseharddimensionsin,youcanstartfillingintheblanks.Inmanycases,thegeometryitselfwillgiveyoutheanswers.Justlikefindingthehypotenuseofthetriangles,alotofthedimensionswillfillthemselvesinbasedonthedimensionsyoudohave.Or
moreaccurately,thosedimensionswon’tbeneededtofullydefinethemodel.
Lastly,you’llneedtomakesomejudgmentcallstofillinthedimensionsyoucouldn’tmeasureandcan’tbedeterminedwithsimplegeometry.Thesewillusuallybethingslikeanglesandradiiforfilletededges.Luckily,thesearethefeaturesthatlendthemselvesthemostto
makinginferences.
That’sforacoupleofreasons:theyusuallydon’thavetobeperfectfortheparttofunctionproperly,andthey’refairlyeasytogetrightwithouttakingmeasurements.Filletsareoftenjustcosmeticandaren’tevenintegraltothefunctionofthepart.Iftheyareimportant,it’sokaybecausethey’restillprettyeasytoguessat.
Anglesaremorelikelytobeimportanttothepart’sfunctionality.Butthey’realsoeasiertodetermine.Designersusuallystickto15°incrementsunlesstheyhaveareasonnotto.Youcanusuallycorrectlyguesstheanglejustbylookingatit.
Inthecaseswherefilletsandanglesaren’tobvious,yourbestbetwillbetrialanderror.Experimentwithdifferent
anglesandradiiuntilitlooksliketherealpart.Thisiswherethehumanknackforcomparisonswillcomeinhandy.Youmaybesurprisedbyhowcloseyou’llbeabletogetthepartjustbydoingthis.
Usingthesemethods,youshouldbeabletosuccessfullyreverseengineermostofthecommonplasticpartsyoucomeacross.You’llbeabletoreplacebrokenthings
aroundthehouse,onyourcar,oranywhereelsesomethingplasticbreaks.Thepartsmaynotcomeoutperfectlythefirsttimeyouprintthem,butwithalittlerefinementandpractice,youshouldbeabletoproducefunctionalreplacementparts.
The Least YouNeed to Know
Reverseengineeringisaveryusefulskillforreproducingandreplacingbrokenparts.
Digitalcalipersaretheonlytoolthehobbyistreallyneedstotakemeasurementsinmostcases.
Fordimensionsthatcan’tbedeterminedwithdigitalcalipers,youcanmakeinferencesandusedeductivereasoning.
Whenreverseengineering,alwaysconsiderthefactthat
thepartwasdesignedbyanotherperson.Thinkaboutwhatthatpersonwouldhavedonewhiledesigningit.
PROJECT
5
MonogrammedCoaster
Project Time: 20minutes
Foryourfirst3DCADmodelingproject,you’regoingtostartwithsomethingsimplethatyoucanproudlydisplayonyourcoffeetable(untilyourspousemakesyoumoveit).You’regoingtobemodelingacustom-monogrammedcoaster!
Thisshouldbeaneasyfirstproject.You’lljustbemodelingabasiccircularplateandcuttingaletterinto
it.Thiswillalsobeeasytoprintafteryou’vemodeledit.
Open YourCADProgram andCreate aNew Part
Obviously,thefirstthingyou’llneedtodoisopenupyourCADprogram.(Inthisexample,likealloftheothers,I’llbeusingSolidworks.)Whentheprogramisopen,youcancreateanewpart.Forthisexample,I’llbeusingmillimeters.Ifyou’dprefertouseinches,justdividethosedimensionsby25.4.
Extrude aCircleTocreatethemainbodyofthecoaster,youshouldstartbyextrudingasimplecircle.Youneedtoselectaplanetosketchonfortheextrudecommand.Choosewhicheverplanemakesthemostsensetoyouforthatspecificpart,butkeepinmindthatyoumight
needtorotatethepartwhenyousliceitinordertoorientitproperly.SoundertheFeaturestab,findtheextrudecommandinyoursoftwareandselectFrontPlane.
Extrudefromthefrontplane.
TheCADsoftwareshouldthenswitchyoutothesketchingtoolbar(oritmayalreadybeopen);inthissoftware,youclickthe
Sketchtab.Selectthecircleicon(definedbythecenterpoint)andclickontheoriginpointtoplacethecenterofthecirclethere.Youcanthenjustdragthecircleoutalittlebit.Choosethedimensioncommandinyoursoftware(youmayneedtochoosethediametertypespecifically)andselectthecircle.Thiswillplaceadimensionthat
definesthediameterofthecircle.Youcanthenmodifythedimensiontofityourneeds;inthiscase,youwantittobe100mm.
Givethecircleadiameterdimensionof100mm.
Withthediameterofthecircledefined,youcangoaheadandextrudeit.Thereshouldbeabuttonfor
completingthesketch(inSolidworks,it’sagreencheckmark,asyoucanseeinthefollowingimage),whichwilltakeyoutothefeature’soptions.Inthoseoptions,giveitanextrudedistanceof10mm.
Extrudethecircle10mmout.
Fillet the TopEdge
Next,youwanttofilletthetopedgeofthecoaster.Thiswillgiveitanice,roundedtop.Roundingthetopwillmakeitmoreaestheticallypleasingandwillalsokeepitfromhavingasharpuncomfortableedge.
ClickontheFeaturestabandselectFillet.UsingtheFillettool,selectthetopedgeofthecoaster.UnderFilletParametersontheleft,
specifyaradiusof5mm.Becausethetopandsidemeetata90°angle,theedgewillberoundeddown5mmonthesideandin5mmonthetop.(Remember,filletsaredefinedbytheradiusofacirclethatistangenttobothsurfaces.)
Filletthetopedgeofthecoasterwitha5mmradius.
Cut the Letter
Thefinalfeaturetoaddtothecoasterisyourinitial(orinitials)cutout.Thiswillbeaddedwiththeextrudedcutcommandinyoursoftware.AfterchoosingthecommandintheFeaturestab,selectthetopsurfaceofthecoastertosketchon.
Beforeyouaddtheletter,youfirstneedtoaddaguidetopositionthetext.Youcouldjusteyeballitandplaceit
whereitlooksgood,butasI’vetaughtyou,it’sbettertofullydefineeverything.Thetext(forasingleletter)willbe60mmhigh,soinordertocentertheletteronthecoaster,youneedtoputaconstructionline30mmbelowtheorigin.
Startbyclickingthelineicontodrawahorizontallinebelowtheoriginpoint.Youthenchangethatlinetoa
constructionlinesoit’snotusedforthefeaturebyright-clickingonthelinethecheckingthe“forconstruction”optioninyoursoftware.Addadimensiontoputtheline30mmbelowtheoriginpoint.
Addaconstructionlinetouseasaguideforthetext.
Youcannowgoaheadandaddthetext.Inthetextcommandofyoursoftware,selectyourconstructionline
astheguide.Next,changethefontoptionssothetextiscenteredandis60mmtall.Chooseafontstylethatsuitsyourtastes,andthentypeinwhateverletteryou’dliketouse.
Cuttheletterallthewaythroughthecoaster.
FinishthesketchtomovebacktotheextrudedcutoptionsintheFeaturestab.Youcaneitherspecifyacut
distanceof10mmorsimplychooseThroughAll(orhoweverit’sspecifiedinyoursoftware),whichwillcutthroughallofthematerialinthatdirection.Oryoucanjustcutinacoupleofmillimetersifyoudon’twantittogoallthewaythrough.Completethefeature,andyourcoasterwillbefinished!
Oncethecuthasbeendone,thecoasterisfinished!
Export the
.STL File andPrintIfyou’resatisfiedwithhowthemodelturnedout,youcanexportitasan.STLforprinting.ThestepstoexportthefilewilldependonyourspecificCADsoftware,butgenerallyyou’lleither“saveas”orexportasan.STL.Whenyouexportit,besure
tochoosemillimeters,becausethat’sprobablywhatyourslicingsoftwarewillbesettoasthedefault.Youalsowanttosaveitatthehighest-qualitysettings,becausethismodelhaslotsofcurvesinit.
Withthe.STLfileinhand,youcangoaheadandprintit.Thismodelwon’trequireanyspecialsettingstoprint,sojustusebasicsettings.Youcanthensimplystartyour
printandletitcoolafterward,andsoonenough,you’llhaveyourveryownmonogrammedcoaster!
Yourprintedcoaster(ifyourinitialhappenstobe“C”).
PROJECT
6
CustomStorageDrawer
Project Time: 1hourYoursecondmodelingprojectisgoingtobequiteabitmoredifficultthanthefirstone.You’llbemodelingacustomstoragedrawerforthestorageshelfyouprintedforproject4.You’llbeabletodesignthecompartmentshoweveryouwishtosuitwhateveryou’dliketostore.
Becausethiswillbeharderthanthefirstmodelingproject,itmaybebeneficialtospendsometimemodelingsomemorebasicdesignsonyourowntogetafeelforthesoftwarebeforedoingthis.I’llalsobeassumingthatyouknowthebasicsofusingthecommandsandsoftware,soIwon’tbegoingovereachfeatureingreatdetail;however,youcancheckoutproject5ifyouneeda
refresheronwheretogoandwhattodointhesoftware.Ifyou’reready,let’sjumprightin!
Open YourCADProgram andCreate a
New PartStartbyopeningyourCADsoftwareandcreatinganewpart.Asusual,myrecommendationistoworkinmillimeters.Thisisespeciallytrueforthispart,becauseitwillbeslidingintotheexistingstorageframe.
Theframewasdesignedinmillimeters,sothebestwaytoensureaproperfitistouse
millimetersforthenewdraweraswell.However,ifyouprefertouseinches,youcandivideallofthemeasurementsby25.4.
Extrude theBody of theDrawer
Forthispart,youneedtostartwithanextrusiononthetopplane.Thisisbecausethemainbodyofthedrawerwillbecreatedbyextrudingfromtheside,andyouwantittolaydownflatonthebuildplatewhenyouprintit.Sointhiscase,thetopplaneactuallycorrespondstothefrontofthepart.
Theopeningintheframeisarectangle25mmtalland
100mmwide,with5mmfilletsonthecorners.Inordertomakethedrawerfitintotheframe,itneedstobeslightlysmallerthanthatopening.Youcandrawthe25×100mmopeningwithconstructionlines,andthenoffsetthoseinsideby.50mm.Youcanthenextrudetheoffsetlinesby100mm(thelengthofthedrawer).
Thedrawerbodyisoffset.50mmfromthe25×100mmopeninginthe
frame.
Cut anOpening for
the HandleThenextfeatureisacutoutthatwillallowroomforthedrawerhandle.Thisissothehandledoesn’tprotrudefromthefrontofthedrawer.Thisdesignchoiceismostlycosmetic,butwillalsohelpthedrawertobeprintableonsmallerprinters.
Tomakethisfeature,youusetheextrudecutcommandin
yoursoftwareonthetopofthepart(orthefrontplane).Makeanarcwitha100mmradius,withitsendpoints15mmfromeachsideofthedrawer.Next,drawalineconnectingtheendpointstomakeitaclosedshape.Youcanthensimplydothecutallthewaythroughthepart.
Cutoutaplaceforthedrawerhandle.
Tofinishthecutout,adda50mmfillettotheendsofthecutout.Thisshouldbewhere
theendpointsofthearcwere.Thepurposeofthefilletsissimplytoroundtheedgeandgiveitamorefinishedlookandfeel.
Design theCompartmentsThisnextstepiswherethecustomizationcomesin.You
essentiallyhollowoutthedraweranddivideitintothedesiredcompartmentsinonefeature.Howyoudivideitupiscompletelyuptoyou.
However,youshouldsticktoafewbasicconventionstomakesurethedrawerturnsoutright.Inmydesign,Igaveallofthewallsa2mmthickness.Thisshouldmakeitsturdywithoutbeingtoobulky,soIrecommendyou
dothesame.
Todothis,startbyoffsettingtheoutsidelinesofthepartby2mmallthewayaround.Next,drawconstructionlinestodivideitupintothedesiredcompartments.Offsetthoseconstructionlinesby1mminbothdirections(tomakethewallsofthecompartments).Thenjusttrimtheoverlappinglinessothateachcompartmentisitsownfully
closedshape.
Designthecompartmentsbasedonyourneeds.However,it’sagoodideatogivethewallsa2mmthicknesstomakethemsturdy.
Fortheoptionsinthe
extrudedcutfeature,choosewhat’susedtoindicate“offsetfromsurface”inyoursoftware.Youcanthenselectthebottomfaceofthedrawer.Enter2.00mm,anditwillcutthecompartmentsdownto2mmfromthebottomface.
Offsetthecut2mmfromthebottomofthedrawer.
Add a Rough
HandleNowyoucanstartaddingabasicdrawerhandle.Youcanusetheextrudecommandinyoursoftware,andusethebottomofthedrawerasareference.
HOT TIPWhy not put the handle
in the middle of the drawer?Because doing so wouldrequire the use of supportmaterial to print the drawer.Extruding it from the bottomwill allow the drawer to beprinted without any supports,which will improve thequality.
Theexactdimensionsyouuse
forthehandleareuptoyou.Butifyouwantthemtomatchtheotherdrawersyou’vealreadyprinted,youcanusethedimensionsshowninthefollowingimage.It’sasimplerectanglecenteredonthepartthatis30mmwideandprotrudes5mmfromthefrontofthedrawer.Theoutsidecornershavea5mmfillet,andthehandleitselfis3mmthick.
Createabasichandlewiththeextrudefeature.
Add Fillets to
HandleAddingfilletstothehandleservestwopurposes:toimprovetheaestheticsandtostrengthenthehandle.Theaestheticreasonsareaprettyobvious:filletededgesjustlooknicer.Butthey’realsoimportantbecausetheymakethehandlestronger.Thegradualtransitiontakesawaytheweakpointthatwould
otherwisebepresentatthe90°edges.
Inthiscase,twodifferentfilletsareused.Ontheverticaledgesoneithersideofthehandle,10mmfilletsareused.Onthetopofthehandle(thehorizontaledge),a3mmfilletisused.Thisgivesitstrengthwhilestillleavingaflatspotforyoutogripwhenopeningthedrawer.
Addfilletstoimprovethelookandstrengthofthehandle.
Add Ridgesfor Grip
Thefinaltwofeaturesyou’llcreatearetheretomakeacoupleofsmallridgesonthehandle.Theirpurposewillbesimplytomakethehandleeasiertogripwhenyou’reopeningthedrawer.
Thefirststeptomakingtheseisasimpleextrusionontopofthehandle.Imademinebydrawing1mm-diametercircles20mmapart,andthenconnectingthemwithlineson
thetopandbottom.Theinsidesofthecirclescanthenbetrimmedaway.Thecenterofthefirstridgeis2mmfromtheedgeofthehandle,andthesecondridgeis3mmfromthat.
Addacoupleofsmall1×21mm
ridgestothetopofthehandle.
Thefinalfeatureis.25mmfilletsallthewayaroundthetopandbottomedgesofbothridges.Thisisjusttosmoothouttheridgesandmakethemmorecomfortableforyourfingers.
Filletthetopandbottomedgesofbothridges.
Export the.STL File and
PrintWiththepartfinished,youcanexportitandprintit.Exportthe.STLfileathigh-qualitysettingstomakesureyouretainthecurvesofthemodel.Youcanthenjustprintitusingthesamesettingsyouusedtoprintthedrawersinproject4andallowtocoolbeforeremoving.
Yourfinisheddrawershouldlooksomethinglikethis,butwith
whatevercompartmentlayoutyoudecidedtomodel.
PROJECT
7
DustCollector
Project Time: 45minutes
Adustcollectorisasimplelittledeviceyoufeedyourfilamentthrough.Inside,asmallspongecatchesanydustthatwasonthefilament.Dustcancausesomemajorheadachesin3Dprinting,includingnozzleclogs,soit’sbesttoavoidtheproblemaltogetherbyusingadustcollector.
Thisprojectalsogivesyouthechancetoexperimentwith
partsthataredesignedtofittogether,helpingyougetafeelfortheaccuracyofyour3Dprinterandhowtodesignpartsthatfitsnuggly.Sobootupthatcomputerandlet’sgetstarted!
Create a NewPart and
Revolve theBodyGoaheadandopenyourCADsoftwaretocreateanewpartinmillimeters.Thebasicdesignofthedustcollectorisprettysimple:ahollowcylinderdividedintotwopartsthatcliptogether.Thismeansyou’llactuallybemodelingtwodifferentparts.
Forthebaseofthefirstpart,startbyusingtherevolvefeatureinyoursoftware.Youcanjustusethesamedimensionsthatareinthefollowingfigure.Theonlyexceptionisthe1.25mmradiusdimensionrightnexttothecenterline,whichisdependentonthesizeofyourfilament.Myfilamentis1.75mm,soImadetheopening2.50mmtogiveitsomeroom.Ifyou’reusing
3mmfilament,you’llwanttomakethatdimensionsomethinglike2mmradius.
Thefirstfeatureisarevolvetocreatethecylindricalshapeofthe
part.
Cut a Groove
Nextyou’llbecuttingagrooveontopofthecylinderfortheclipstofitinto.Thisisaprettysimpleoperationwiththerevolvedcutcommandinyoursoftware.
Usingthesamecenterlinefromtheoriginyouusedfortheinitialfeature,youcanjustdrawacircleattheedgeofthepart.Putthecenterpointofthecircleontheedgeofthecylinderso
it’sconstrainedthere,andthenjustspecifyadiameterof2mmandadistancefromthetopof3mm.
Usetherevolvedcutcommandtocutagroove.
Youthenneedtoaddfilletstothetopandbottomofthegroove.Thiswilljusthelptheclipsfitmorecleanlywhen
thetwopiecesareputtogether.IntheFeaturestab,chooseFilletandspecify1mmfillets.Nextjustchoosethetopandbottomedgesofthegroove,andfinishthefeature.That’sallyouneedtodoforthefirstpart,sojustsaveit.
Fillettheedgesofthegrooveyoujustcut.
Create the
Second Partand Revolvethe BodyNowit’stimetocreatethesecondpart.Thispartisalittlemorecomplicated,butitstartsthesameway:witharevolvedbase.
Justlikewiththelastpart,youcanusethedimensions
fromthefollowingimagetocreatetherevolve.Again,youmayneedtochangethedimensionclosesttothecenterlineifyouhave3mmfilament.
Thesecondpartalsostartswitharevolve.
Make the
First ClipYoucan’tjustextrudetheclipsbecauseyouneedthemtofollowthecurveofthecylinderinordertofunctionproperly.Soyoushouldusetherevolvecommandinyoursoftware.
Onceagain,youcanusethedimensionsfromthefollowingimage.Ifyou’rereallypayingattention,you
maynoticeit’soffsetoutandupby.25mmcomparedtowhereitshouldbebasedonthefirstpart.Thisistogiveitalittleclearance,sothetwopartsfittogethermoreeasily.
Whenyouactuallyfinishtherevolve,don’tdoitafull360°.Youwanttheclipstobeflexible,soyoushouldonlyrevolveitbyasmallamount.(Iused30°onmine.)
Therevolvecommandshouldbeusedfortheclip,soitfollowsthe
curveofthecylinder.
Copy the Clip
Toavoidhavingtoremodeltheclipthreemoretimes,youcanusethecircularpatternbuttonintheFeaturestab.Butinordertousethatcommand,youneedtofirstcreateanaxistouseasareference.Thisiseasyenough;justcreatetheaxisbyselectinganyofthecylindricalsurfaces.
Createanaxistouseforthecircularpatterncommand.
Withtheaxiscreatedforreference,youcanpatterntheclip.Selectthefirstclip,andthenselectthecircularpattern
command.UnderParameters,selecttheaxisofrevolution,typein90.000toseparatetheclipsby90°,andenter4forthenumberofclips(theoriginalplusthethreecopies).
Useyourcircularpatterncommandtocopytheclip.
Finally,addsomefilletstotheedgesoftheclips.Thiswilljustmaketheclipsalittlebitstronger.
Filletsalleviatestressesonedgesandmakethepartstronger.
WATCH OUT!You could have added
fillets to the first clip andthen patterned it along withthe rest of the clip, but I’vefound that patterningmultiple features togethersometimes causes errors.
Youcanseehowthepartswillcliptogetherinthissectionview.
Export the
.STL Filesand PrintAsyou’vedonewiththepreviousprojects,youjustneedtoexportthepartasan.STLtoprintit.Theonlydifferencehereisthatyou’llneedexportbothparts.Youcanthenloadbothpartsatthesametimeandslicethemtogethertobeprinted.Todo
this,justloadthefirstpartandthenthesecondpart.Thepartsshouldautomaticallybeplacednexttoeachotherforslicing.Fromthenon,youslicethepartsthesamewayasyounormallywould.
Bothpartscanbeprintedatthesametime.
Onceyourpartsaredoneprintingandcooled,youcanstartusingthemtocollectdust.Allyouhavetodois
feedthefilamentthroughtheholes,cutoffasmallpieceofahouseholdspongeandputitaroundthefilament,andthenclipthetwopiecestogether.Asthefilamentslidesthrough,thespongewillcollectanydustonthepart.
Thetwopartsshouldbeabletocliptogether.Iftheydon’t,youcantrytweakingthedimensionstoexperimentwithhowpartsfit
together.
PROJECT
8
ReverseEngineering
aUseful Part
Project Time: 30minutesThisprojectwillinvolvereverseengineeringapartfromaroundyourhouse:anelectricalsocketcover.Whyasocketcover?Becauseeveryonehasoneintheirhome,soit’ssomethingeveryonewillbeabletofollowalongwith.I’llbemodelingastandardU.S.
socketcover,buttheprocessshouldbeprettysimilarforotherkindsofsocketsinothercountries.
AstandardU.S.electricalsocketcover.
Theideahereisthatyou’llbelearninghowtotakemeasurementsfromtheoriginalpart.SoIwon’tbe
providingyouwiththeactualdimensionsIusedinmostcases.Instead,you’llbeinchargeofcomingupwiththemeasurementsyourself.
Create a NewPart andExtrude the
BodyOpenupyourCADsoftwareandcreateanewpart.Asalways,Ipersonallyprefertoworkwithmillimeters.Butyou’rewelcometouseinchesifyouprefer,especiallysinceyou’llbetakingthemeasurementsyourself.
Youcanstartbymodelingasimplerectangletogettheoverallbodyofthecover
done.Youwanttoextrudeoffofthefrontplane,soitliesflatonprintbed.Justmeasurethelengthandwidthofthecovertodrawarectangle,andmakesureit’scenteredontheorigin.Next,measuretheoverallthicknessofthecoverfortheextrusionthickness.
Modelasimplerectangularsolidforthebodyofthecover.
Fillet the
EdgesAsI’msureyou’venoticed,theoutsideedgesofthesocketcoverarerounded.Thisisreallyjustacosmeticfeature,butit’sonewhichiseasytoadd.
Yousimplyneedtofilletthetopoutsideedgesofthecover.Becauseit’sjustcosmetic,youdon’tneedtogettheradiusofthefillet
perfect;justpickaradiusthatlooksrighttoyou.
Filletthetopedgestoimprovetheaesthetics.Asyoucanseehere,Iusedaradiusof3mm,buttheradiusyouuseisentirelyupto
you.
Shell theCoverUnlikethefillets,thisfeatureisimportanttothefunctionalityofthepart.You’llneedtousetheshellcommandinyoursoftwaretoessentiallyhollowoutthecover.Todothis,youfirstneedtomeasurethethicknessoftheplasticthatmakesup
thecover(nottheoverallthickness).
Measurethethicknessoftheplasticthatmakesupthecover.
Onceyouknowthethicknessoftheplastic,youcanthencreatetheshellfeature.Todothis,youneedtospecifythat
thicknessyoumeasured,aswellasthefaceyou’dliketodelete.Inthiscase,youwanttodeletethebackfaceofthecover(oppositeofthefillets).
Createtheshellbyspecifyingthethicknessandwhichfaceyou’dlike
toremove.
Cut OneSocketOpeningNowit’stimetogoaddanextrudedcutfortheopeningfortheactualsocket.Ifyoulookclosely,you’llseethatit’sactuallyarelativelysimplecutout.It’smadeupoftwostraightlinesthatare
connectedbytwoarcs(atleastontheU.S.socket).
Youcanmodelthisinanumberofdifferentways,butIrecommendyoustartwiththetwostraightlines.Drawthembasedontheirlengthanddistancefromthetop(theyshouldbecenteredfromlefttoright).
Next,youcandrawthearcs.Youknowtheirendpoints(thestraightlines),soyou
justneedtofigureoutthemidpointsofthearcs.Youcandothatbymeasuringthewidthatthewidestpointanddrawingaconstructionlinecenteredbetweenthetwostraightlinestorepresentit.Youcanthenjustdrawanarcwithitsendpointsonthestraightlines,anditsmidpointontheendoftheconstructionline.
Cuttheopeningfortheelectricalsocket.
Mirror the
SocketOpeningTheopeningsfortheelectricalsocketsaresymmetrical,soallyou’llneedtodotomakethesecondopeningistomirrorthefirst.Selectthemirrorcommandinyoursoftwareandusethetopplaneasthemirrorplane,withthefirst
openingasthefeaturetomirror.
Mirrorthefirstsocketopeningtocreatethesecond.
Create the
Screw HoleSupportOnthisparticularsocketcover,thereisadditionalmaterialonthebackwherethescrewholegoesthrough.Thisistoaddsupportforthescrew,whereitpushesagainsttheoutletmountedonthewall.Therearealsosomeribsontheback,butthey’re
probablynotintegraltothefunctionofthepart.
Thisisaprettysimplefeature—justarectangularsupportwithroundedcorners.Tobegin,measurethelength,width,anddepthofthesupportusinganactualsocketcover.
HOT TIPMeasuring the width
and length are easy enough,but the depth is a littleharder. If your calipers havea depth gauge at the end,this is one feature where itwill come in handy. If younot, you’ll just have measureit as best as you can.
Measurethelength,width,anddepthofthesupport.
Thecornersofthesupportarerounded.However,theexactradiusalmostdefinitelyisn’tgoingtoaffecthowwellthe
partfunctions.Sojustestimatetheradiusofthefilletsasbestasyoucan.
Addfilletstoroundthecornersofthesupport.
Add theScrew Hole
Thescrewholeonthispartiscountersunktoallowthescrewtositflush(oralmostflush)withthesurfaceofthecover.Tomakethis,startbymeasuringthediameteroftheactualhole(thisiseasiesttodofromtheback)andcutthat.
Finally,youneedtoaddthecountersink.Thiscaneasilybecreatedbyusingthechamfercommandinyour
softwareontheedgeofthehole.However,youneedtoknowtwothings:chamferdistanceandangle.Thedistanceiseasyenough;allyouhavetodoismeasurethediameteratthetopofthecountersinkanddivideitby2.Theanglewillbehardertomeasure,though.However,45°isaprettysafeassumption,becauseit’scommonlyusedforcountersunkscrewholes.
Achamfercanbeusedtoaddthecountersink.
Export the.STL File and
PrintThebestwaytodeterminehowwellyoumeasuredandmodeledthepartistoactuallyprintitoutandtryit.Youcanexportitthesamewayasanyotherpart,andIrecommendusingthehighest-qualitysettings.Whenyouprintit,youshouldn’tneedtouseanysupports,andyoucanprobablygetawaywitha
moderateinfill(like25to50percent).Letthepartcoolbeforeremoving.
Thefinishedcovermountedonthewall,anditfitscorrectly!
PART
5
AdvancedUsage andTechniquesIfyou’vealreadyreadthe
firstfourparts,you’repracticallya3Dprintingexpertalready.Sointhispart,Iintroduceyoutosomemoreadvancedtechniquesandusesforyour3Dprinting—thingslikeprintingwithmoreexoticmaterials,usingmultipleextruders,andsomepopularmodificationsyoucanmaketoyour3Dprinter.Ialsotellyoualittlebitaboutsomeusesforyour3Dprinterthatyoumaynothaveeven
realizedwerepossible.
CHAPTER
18
Printingwith OtherMaterials
In This Chapter
Uniquefilamentmaterialsyoucanprintwith
Specialhardwareneededtoprintcertainmaterials
Settingsyou’llneedtochangetosupportothermaterials
Throughoutthisbook,I’vebeentalkingalmostexclusivelyaboutprinting
withPLAandABSfilament.Thereasonforthatisprettysimple:they’rebyfarthemostpopularfilamenttypesonthemarket.Thevastmajorityofallhobby3Dprintingisdonewiththosetwomaterials.
ButaspopularasPLAandABSare,therearemanyothertypesoffilamentmaterialonthemarket.Noneoftheseareevencloseto
approachingthepopularityofPLAorABS,buttheydohavetheiruses.Mostofthemarespecialtymaterialsdesignedtobeusedforparticulartypesofprints.Inthischapter,Igooversomedifferentmaterialsyoucanuse,aswellaswhatalterationsyou’llneedtomakeinhardwareandsettingstoprintthem.
WhatMaterials AreAvailable?Sowhatotherfilamentmaterialsareonthemarket,andwhatkindofprintsaretheyidealfor?Whilenewfilamentmaterialsarebeingdevelopedandreleasedallthetime,thesearesomeofthe
oneswhicharegainingpopularitynow.
NylonNylonisaverycommonplastictypethathasbeenpopularfordecades.It’srecentlybecomeavailableinfilamentformfor3Dprinters.Thedesirablepropertiesofnylonareitsstrengthanditslowcoefficientoffriction.
Partsthatarepartofamovingsystem,suchasbushingsandslides,areusuallymadefromnylonbecauseofitslowfriction.Sonylonfilamentisgenerallyusedforthesamepurpose:toprintpartswherefrictionisaconcern.
PolycarbonateAnothermaterialthathas
beenaroundforaverylongtimeispolycarbonate.Polycarbonateisaverystrongmaterial,makingitidealforapplicationswheredurabilityandimpactresistanceareimportant.Forexample,bulletproofglassismadefromlaminatedlayersofpolycarbonate.
WATCH OUT!Please do not attempt
to shoot something you’veprinted in polycarbonate. It’svery strong, but bulletproofglass is made using a veryspecific manufacturingprocess, and regularpolycarbonate will not stop abullet. So go ahead andforget any ideas about 3Dprinting bulletproof armor orsomething.
Soifincrediblyhighstrengthisrequiredina3Dprintingapplication,polycarbonateisagoodchoice.Infact,it’sprobablythestrongestfilamentcurrentlyavailableforconsumer3Dprinters.
Flexible FilamentI’vetalkedaboutflexiblefilamentsafewtimesalready,soyou’reprobablyalreadyat
leastalittlebitfamiliarwiththeidea.Flexiblefilamentisagenerictermusedtodescribeanyoftheflexible,rubberyfilamentmaterialsavailablefromahandfulofmanufacturers.Theactualformulasusedvaryfrommanufacturertomanufacturer,sothesearereallygroupedbytheirproperties(notbecausethey’reaparticularkindofplastic).
ThispartwasmadefromNinjaFlex,apopularbrandof
flexiblefilament.
Flexiblefilamenthasgrowninpopularitytremendouslyoverthepastcoupleofyears.
Inthehobbymarket,it’softenusedforthingslikerobotorRCtires,grips,andanythingelsethatrequiresarubberlikefeel.Withadualextrudersetup,it’spopulartoprintbothflexiblefilamentandatraditionalhardfilamentinthesamepart.Forexample,youcouldprintawheelandtireasasinglepiecefromthetwodifferentmaterials.
Wood FilamentOnefilamentmaterialthatisprettysurprisingandunusualis“wood”filament.Thereareonlyacoupleofmanufacturerscurrentlymakingthisfilament,soit’squiteunique.Thematerialitselfisessentiallyamixofpolymerandwoodfiber.
Whenprinted,thematerialactuallylooksremarkably
likewood.Infact,itcanevenbesandedjustlikewood.Theappealisobvious:youcan3Dprintobjectsthatlooklikethey’remadeofwood.
PETPolyethyleneterephthalate(PET)isanotherplasticthathasbeenaroundinvariousformsfordecades.It’soneofmanyplastictypesthatare
commonlyusedinawiderangeofproducts,frombottlestotapes.Asfarasmechanicalpropertiesgo,it’sfairlysimilartootherfilamentmaterialsonthemarket.
TheprimaryadvantagethatPEThasoverotherfilamentsishowwellitprints.IthasstrengthsimilartoABSbutdoesn’trequireaheatedbedanddoesn’twarpmuch(ifatall).Basically,itcombines
theadvantagesofPLAandABSwhileavoidingtheirdisadvantages.However,PEThasonlyrecentlybeenmadeavailableintheformoffilament.It’sonlybeingmadebyacoupleofmanufacturers,soit’sstillalotmoreexpensivethanPLAandABS.
HIPS
High-impactpolystyrene(HIPS)hastraditionallybeenusedforplasticpartsthatdon’trequirealotofstrength(likepackaging),butithasgainedanewusein3Dprintingasasupportmaterial.Inadual-extruder3Dprinter,HIPScanbeusedasthesupportmaterialwhileanothermaterialisusedfortheactualpart.
ThereasonthatHIPSiswell
suitedforthisapplicationisbecauseitdissolvesinlimonene.Theprimarymaterialdoesn’tdissolveinlimonene,sothisisidealbecausethesupportmaterialcanberemovedchemicallyinsteadofwithapairofpliers.Whilethereareotherfilamentmaterialsthatarealsosuitableforthistask,rightnowHIPSisthemostcommon.
HardwareNeededIt’sprobablynotsurprisingthatsomeofthesematerialswillrequirespecialhardware.Asnewmaterialsareaddedtothemarket,it’slikelythatthehardwarerequirementswillbecomeevenmorespecialized.Ican’tcovertherequiredhardwareforallof
thefilamentmaterials,soinsteadI’llgiveyouanideaofwhatkindofhardwareiscommonlyneeded.
All-Metal Hot EndsAll-metalhotends,asI’vetouchedonpreviously,aresimplyhotendswhichareconstructedentirelyfrommetal.Traditionalhotendsaremadefromacombination
ofmetalandplastic,whichisadequateforstandardhotendtemperatures.ButalotofthesematerialsrequirethatthehotendbemuchhotterthanisnecessaryforABSorPLA.
Someofthesematerialsneededtobeprintedattemperaturesof300°Corhigher.That’ssimplytoohotfortraditionalhotendconstructions,whichcan
becomedamagedattemperaturesthathigh.All-metalhotendscanhandletheseextremetemperatureswithoutbecomingdamaged.
HOT TIPAll-metal hot ends are
becoming very popularbecause of their high-temperature capabilities. Butthey’re not perfect for allsituations. Many all-metalhot ends are prone toclogging and jamming, soit’s usually not worth addingone to your 3D printerunless you know you needto print at high temperatures.
Print FansI’vealreadytalkedabouthowimportantprintfansareinChapter10.They’reveryhelpfulforsomefeatures,likebridgesandsmalllayers.Butsomematerialsrequireaprintfaninordertoprintatall.
Printfansexisttoquicklycoolthefilamentafterithasbeendepositedontothebedorthepreviouslayer.
MaterialslikeABSsolidifyprettyquicklyontheirown,soafanisn’tnecessary.Butothermaterialsaremorefinickyandhavetobeactivelycooledinordertosolidifyquicklyenough.
Ofcourse,printfansingeneralareagoodideaanyway,soit’sdebatablewhethertheyshouldevenbeconsidered“specialtyhardware.”Butstrictly
speaking,theyaren’tnecessaryforallprintsandmaterials,makingthemoptional.It’salsoworthmentioningthattheresultsfromafanalonearen’talwaysgood.Sometimesit’snecessarytoaddafanshroudtodirectthecoolairinordertogetgoodresults.
TheLulzbotTAZcomeswithashroudforthefantodirectcoolair
justbelowthenozzle.
Heated Beds andBed Materials
YoualreadyknowthatheatedbedsarerequiredforprintingABS,butthereareothermaterialsthatrequireaheatedbedaswell.Plussomematerialslikenylonevenbenefitfromspecialbuildplatformmaterials.Traditionaladhesionimprovementmethodsdon’talwaysworkforallmaterials.Therefore,somematerialshavetheirownuniquetechniquesformakingsure
thefilamentstickstothebed.
FASCINATING FACTPhenolic resin plastic
was the very firstcommercially availablesynthetic resin. It wasoriginally sold by theBakelite Corporation, andwas immediately popular ina wide range of products.Since its invention, it hasbeen used to make virtuallyeverything plastic at onetime or another.
Atfirst,thatmaysoundtrivial,butitcanactuallybeafairlybigdealforsomematerials.Forexample,nylonfilamentreportedlyadheresbesttophenolicresin(usuallyknownbythetradenamesGaroliteandBakelite).Differentfilamentmaterialshavedifferentidealbedmaterials,andit’softenhelpfultoswitchbetweenbedmaterialsdependingonthefilamentyou’reusing.
Forinstance,aglassbedworkswellforABSandPLA,butyoumaywanttoswitchtoGarolitefornylon.
PrintingTechniquesAsyouprobablysurmisedalready,allofthesefilamentmaterialsdon’tjustrequire
specialhardware.Inadditiontothathardware,thedifferenttypesoffilamentalsorequirespecificsettings.JustlikehowyouhavetoadjustthesettingswhenyouswitchbetweenPLAandABS,youhavetoadjustthesettingstousethesemoreexoticfilamentmaterialsaswell.
Temperature
Theprinttemperatureisthemostobvioussettingthatwillprettymuchalwaysneedtobeadjusted.Almostallfilamentmaterialshavetheirownidealtemperaturesetting,andtherangecanbe100°Cormore.Thefilamentmanufacturershouldhavesomeinformationonwhattemperatureisidealfortheirfilament,sobesuretocheckwiththemfirst.Forexample,PLAisusuallyprintedaround
200°C,ABSat230°C,nylonat250°C,andsoon.IfyoutriedtoprintatPLAtemperatures,itwouldn’tevenextrude.PLAprintedatnylontemperatureswouldburnorpoolonthebed.
Adjustingthefilamenttemperaturewithinthefilamentsettings.
Onceyouhaveanideaofwhatthetemperatureshouldbe,it’sbesttoexperimentalittletofindwhatgivesyou
thebestresults.Thatparticularfilamentmayprintbetteronyourprinterwhenit’salittlecoolerorhotterthanrecommended.Printafewsmallpartstogetyourtemperaturedialedin,andthensaveitasaconfigurationforthatmaterial.
Youshouldalsofollowthesamestepsforthetemperatureoftheheatedbed.Somematerialswon’t
needtheheatedbedtobeonatall,whileothersmightneedittobeveryhot.However,thetemperatureofthebedismuchmoreforgivingthanthetemperatureofthehotend,soaslongasyou’rewithin10°Corso,itshouldworkjustfine.
SpeedPrintspeedisanothermajorvariablewhenyou’reswitchingbetweenfilamentmaterials.Manyofthemoreexoticmaterialshavetobeprintedveryslowlyandwillproducepoorresultsifthey’reprintedtooquickly.Thisisbasicallydeterminedbyhowquicklythatparticularmaterialcanmeltinthehotend,whichcanbe
dramaticallydifferentbetweenmaterials.Forexample,PLAcanusuallybeprintedatveryfastspeedsbecauseitflowswell.Nylon,ontheotherhand,usuallyneedstobeprintedslowly(around40mm/s)oritwon’tbondproperlytoitself.
Justlikewiththetemperaturesettings,youshouldstartbylookingatwhatthemanufacturerrecommends.If
thatinformationisn’tavailable,dosomesearchingtofindoutwhatsettingsotherpeopleareusingforthesametypeofmaterial.Onceyou’vegotsomenumberstostartwith,youshouldfine-tuneitbyprintingafewparts,justlikeyoudidafteradjustingthetemperaturesettings.
Cooling
Asyoulearnedearlierinthischapter,somematerialswillrequireactivecoolingwhileothersshouldn’tbecooledatall.Onceagain,thisinformationcanusuallybefoundfromthemanufacturerofthefilamentorbysearchingaroundtoseewhatothersaredoing.Butcoolingcanbealotmoresubjectivethantemperatureandspeed.
Forsomematerials,you’ll
wantthefanonatfullblastallthetime.Forothers,itshouldn’tbeturnedatall.Thereisalsoalotofmiddlegroundwhenitcomestousingafan.Youcanhavethefancomeonjustforcertainfeatures(likebridgesoroverhangs),orthefancouldbeonalowspeed.Forexample,PLAvirtuallyrequiresaprintfantoturnoutwell.However,ABSshouldonlyhavethefanonfor
extremebridgeoroverhangs;otherwise,itwillwarp.Asageneralruleofthumb,tostartyourexperimenting,thefanshouldbeoffformaterialsthatarepronetowarping,whilematerialsthatdon’thavethisissuecanusuallybeprintedsafelywiththefanon.Gettingyourcoolingsettingsrightwilldefinitelytakesomepatienceandexperimentation.
Sohowdoyougetitadjusted
properly?Startbyrunningaprintwiththefanonhightheentiretime.Youcanthentryrunninganotherprintwithitoffcompletely.Comparetheresultsandseewhichoneworkedbetter.Onceyouknowhowthematerialreactstocooling,youcanstartadjustingthesettingsforparticularfeatures.Forexample,youmighthavethefanoffcompletelyforthefirstfewlayers,onlowfor
therestoftheprint,andonhighforbridgesandoverhangs.Thepointis,you’llneedtolookattheresultstoseewhatworksbest.
Layer ThicknessThisisasettingyoumaynotexpecttohavetochange,andinmostcasesyouwon’t.Butasmallminorityoffilament
materials(suchasnylon)canbeabitsensitivewhenitcomestolayerheight/thickness.Unlessthefilamentmanufacturerrecommendsotherwise,it’sbesttostartbyusingwhateverlayerheightyouwouldnormallyuse.
Butifyou’regettingpoorresults(especiallyinconsistentextrusionandpoorsurfacequality),layer
thicknessmaybetheculprit.Whenthishappens,it’salmostalwaysbecausethelayerheightistoosmall,sotryincreasingitalittlebitandseeifthatimprovesyourresults.Inextremecases,youmayevenhavetoswitchyournozzleoutforsomematerialsthatsimplydon’tflowwellthroughasmallnozzle.
The Least You
Need to KnowTheoptionsforfilamentmaterialsarerapidlyincreasing,andthereisnowaprettylargevarietyofmaterialsavailableonthemarket.
Somematerialsarebettersuitedtoparticularprintsthanothers.Youshouldpickthematerialbasedonyourneedsforspecificparts.
Manymaterialsrequire
specifichardware—suchasall-metalhotends,printfans,andheatedbedsandbedmaterials—inordertoprint.Beforeyouorderanewfilamenttype,besuretocheckthatyour3Dprinteriscapableofprintingit.
Theprintsettingswillalmostalwaysneedtobeadjustedfornewmaterials.Besuretotakethetimetotweakyoursettingsuntilyou’regettinggoodresultswithanewmaterial.
CHAPTER
19
ModifyingYour PrinterIn This Chapter
Addingfanshroudsorheated
bedsMakingtheswitchtoall-metalhotends
Installingextrudersandextendingaxes
Modificationsformillingorlasercutting
Sitesforpurchasingpartsorfinding3Dmodelstoupgradeyourprinter
Onceyou’recomfortablewithyour3Dprinterandhavegottenboredwithprinting
pencilholdersandcoasters,you’llprobablystartthinkingabouthowyoucanupgradeormodifyyour3Dprinter.Thereareanendlessnumberofmodificationsyoucandotoyourprintertomakeitbiggerandbetter,andifyou’rethetinkeringtype(whichyouprobablyareifyou’rereadingthisbook),I’msureyou’reeagertogetyourhandsdirty.
Youcanreallymodifyeverythingonmostprinterswithenoughwork.Afterall,youhavea3Dprinteryoucanusetomakenewpartsforupgrades.Butthereareahandfulofpopularmodificationsthatyoucandotomost3Dprinterstoimprovetheirfunctionality.Sointhischapter,let’stakealookatsomeofthemorecommonupgradesandmodificationsyoucando!
Adding a FanShroudIfyour3Dprinterdoesn’talreadycomewithafanshroud,addingoneisdefinitelythemostpopular3Dprintermodification.Infact,it’susuallythefirstmodificationpeoplemaketotheir3Dprinters.
WATCH OUT!Attempting to modify
your printer always carrieswith it the risk of damagingthe printer. It’s also likelythat your warranty (if youhave one) will be voided bythe modifications. Therefore,make any modifications andupgrades with the risks inmind.
Whilemanymanufacturers
includeaprintfanwiththeprinter,it’softenjustasmallfanblowinginthegeneraldirectionofthenozzle.Fanshroudsimprovethesituationbyactingasafunneltodirectandfocustheairjustbelowthenozzle.Doingsousuallyimprovesthecoolingcapabilitiesofthefanquitedramatically.Whileyoushouldn’texpectmiracles,afanshroudcandefinitelymakeadifference.
ThePrintrbotSimpledoesnotcomewithafanshroud,butPrintrbotsuppliesaprintablemodeltoaddoneyourself.
Addingafanshroudisusuallyafairlyeasyjob.Most3Dprintermodelson
themarkethavefanshroudsalreadymodeledandavailablefordownload.Inmanycases,you’llbeabletoattachtheshroudusingthemountingscrewsthatarealreadyontheprinterforthefan.
Soallyouneedtodoisfindafanshroudmodelforyour3Dprintermodelandthenjustdownloadandprintit.Onceit’sfinishedprinting,youcan
justmounttheshroudtothefan.Youshouldimmediatelyseeacoolingimprovement.
Adding aHeated BedIfyour3Dprinterdidn’tcomewithaheatedbed,yourmaterialoptionsaregoingtobeprettylimited.PLAwillbe
theonlycommonlyavailablematerialyoucanprintsuccessfully.NowPLAisactuallyareallygreatmaterialthatprintswellandisreasonablystrong,butit’salwaysnicetohavetheoptiontouseothermaterials.
Todothat,youneedtoaddaheatedbedtoyour3Dprinter.Thedifficultyofdoingthisdependsonthreemajorfactors:howlargethebedis,
thecontrolboardyou’reusing,andthepowersupplyyou’reusing.
Bed SizeGeneric3D-printedheatedbedsusuallycomeinarelativelysmallselectionofstandardsizes.Ifyourbedsizeissomethingcommonlike6×6inches,findingaheatedbedshouldn’tbe
difficult.Butifyou’relookingforsomethingstrangelike3×9inches,you’reprobablynotgoingtohavemuchluckfindingone.
Itispossibletomakeyourownheatedbedinwhateversizeyoulike,butit’snoteasytodo.You’dessentiallyhavetomakeyourownprintedcircuitboard(PCB)atthesizeyouneed,andyou’dhavetomakesurethetraces
werethecorrectsizetogettheresistanceright.Oryoucancontactaheatedbedmanufacturerandhavethemmakeyouacustombed,butthatwillbealittlepricey.
HOT TIPThe heated bed
doesn’t have to be exactlythe same size as the buildplatform. As long as itcovers the print area (or isclose to it), it should workfine. For example, if yourprint bed is 150×150mm, a6×6-inch heated bed(152.4×152.4mm) wouldprobably work just fine.
However,thatshouldn’tbeanissueformostpeople.3Dprintersgenerallycomewithprettystandardbedsizes,sofindingtherightsizeforyourprintershouldn’tbetoodifficult.
Control BoardInordertoaddaheatedbed,yourcontrolboardhastohaveanoutputtopowerit
andaninputforthethermistor(whichmeasuresthebed’stemperature).Mostmoderncontrolboardswillhavetheoutputandinputfortheheatedbed,butnotallwill.
Ifyourcontrolboarddoesn’thavetheconnectionsfortheheatedbed,you’llneedtoupgradetoacontrolboardthatdoes.Therearemanycontrolboardsonthemarket
thatshouldbecompatiblewithjustaboutany3Dprinter.Changingcontrolboardswilltakeafairamountofrewiringwork,buttheprocessisusuallywelldocumentedonwebsiteslikeRepRap.org.
Ifthecontrolboardalreadyhastheheatedbedconnections,addingtheheatedbedwillbesignificantlyeasier.However,
ifthebedislarge(over8×8inches),you’llalsoneedtomakesureitcanhandlethecurrentrequiredforthebed.Forexample,ifthebeddraws15ampsandthecontrolboardcanonlyhandle10amps,you’llhaveaproblem.Butthatshouldonlybeanissueforlargeheatedbeds.
Power Supply
Thefinalconcernwhenaddingaheatedbediswhetherornotthepowersupplycanhandleit.Heatedbedsusealotofpower,sothepowersupplyhastobeabletoprovidethepowerfortheheatedbedaswellastherestofthe3Dprinter.It’snotuncommonforthestockpowersupplytobeinadequateonceaheatedbedhasbeenadded.
Luckily,upgradingthepowersupplyisaprettyeasyjob.Powersuppliescomeinavarietyofstylesandformfactors,withallkindsofdifferentconnections.Someprintersuselaptop-stylepowersupplies,whichmeansyou’llneedtomakesurethejackistherightsizeandshape(inadditiontoitmeetingthepowerrequirements).
WATCH OUT!Rewiring your printer,
especially when it comes tothe power supply, can bepotentially dangerous. It’spossible to improperlyconnect the wires, whichcould result in electrocutionor fire. Be sure you knowwhat you’re doing and usethe proper safetyprecautions when doing thiskind of work.
Otherprintersusegenericpowersuppliesthathavebareconnectorsyousimplescrewwiresinto.Thosearetheeasiesttoreplace,becauseyoujusthavetogetamorepowerfuloneandswitchthewiresover.Theyalsotendtoberelativelyinexpensive.
ManypeoplealsousedesktopcomputerATXpowersupplies.They’reidealbecausethey’recheap,
readilyavailable,andcanputoutalotofpower.However,theyusuallyhavetobejury-riggedtoworkwith3Dprintersbecausetheyhavebuilt-inswitchesandsafetymechanisms.Butthey’reagreatoptionforsupplyingalotofpoweronabudget.
Ifthenewpowersupplydoesn’thaveapowerconnectorthatmatchestheoriginal,you’llneedtodo
somerewiringforthismodificationaswell.Luckily,thisisusuallyasimplematterofcuttingofftheoldconnectorsandinstallingnewmatchingconnectors.Mostpowersupplieswillonlyhavetwowires(positiveandnegative)thatarecolorcoded(blackandwhiteorred),whichjustconnecttothecorrespondingcolorsontheotherend.
AstandardATXcomputerpowersupplyconvertedforusewitha3D
printer.
Switching to
All-Metal HotEndsInthepreviouschapter,Italkedabouthowall-metalhotendsarerequiredforsomematerialsbecauseoftheirhightemperaturerequirements.Forthatreason,ithasbecomeverypopulartoswitchoutthestandardhotendforanall-metalmodel.
Makingthatswitchisusuallyprettyeasytodo,butlikeallthingsitcanbecomecomplicated.
Manufacturersofaftermarketall-metalhotendspurposefullymakethemsothey’reeasytoaddtoyourprinter.Obviously,it’sintheirbestinteresttomakethemasuniversalaspossible.Butthey’restillnotquiteplug-and-play.
Therearetwofactorshere:physicallymakingtheconnectionsandmountingthehotend.Makingtheconnectionsisusuallyassimpleasjustsplicingfourwires(twofortheheatingelementandtwoforthethermistor).Thesmallerwireswillbeforthethermistor,andthepolaritywon’tmatter.However,you’llusuallyneedtoreconfigureyourfirmwarefor
thenewthermistoraswell(whichentailschangingthethermistormodel).
Actuallymountingthehotendcanbealittlemorecomplicated.Thereareafewsomewhatstandardizedmounttypes,andthenahandfulofcompletelyuniquewaysofmountinghotends.Ifyourprinter’shotendisoneofthestandardmounts,youcanoftenjustswapoutthe
hotend.Insomecases,youmayneedtofirstprintsomekindofadapterifthemounttypesarestandardbutdifferent.
Itonlybecomesaseriousheadacheifyourprinterhasanunusualtypeofhotendmount.Somemanufacturersusecompletelyproprietaryhotendsthathaveuniquemounts.Inacaselikethat,you’lleitherneedtofindan
adapter(orentirelynewextrudercarriage)that’salreadybeenmodeledbysomeoneelseormodelyourown.
HOT TIPHot end compatibility is
definitely something youshould look into beforeordering an all-metal hotend. Do some searching onthe forums for your 3Dprinter and see what other
people are doing. Is there aspecific model of hot endthat people prefer? Maybesome fit better than othersand are easier to mount. Ifso, that can help you decidewhat hot end to order.
InstallingMultiple
ExtrudersAddinganadditionalextrudertoyour3Dprinter(orafewadditionalextruders)isaveryexcitingmodification.Itopensupawholenewsetofpossibilitieswhenitcomestowhatyoucanprint.Youcanprintinmultiplecolors,indifferentmaterials,orwithadedicatedsupportmaterial.Butit’salsoaprettydifficult
modificationtomake.
Some3Dprintermanufacturershavekitsavailabletoupgradeyourprintertoadualextrudersetup.Forexample,Lulzbothasanupgradeavailablefordualextruders.ButI’mnotawareofanythatcurrentlyhavekitsavailableforaddingmorethanoneadditionalextruder.Andit’snotparticularlycommonforthem
toevensellthose.
Thisisadrop-indualextruderdevelopedbyLulzbotfortheirTAZ
43Dprinter.
Formostpeople,addingoneormoreextrudersendsupbeingacompletelycustomjob.You’llneedtodesignanewextrudercarriagewithmountsfortheextruders,upgradeyourcontrolboardtoonewithmultipleextruderconnections,andreconfigureyourfirmware.Noneofthatiseasytodo,andcanbequitecomplicated.TheRepRap
forums(forums.reprap.org)areagoodplacetolookforinformationondoingthiskindofextensivemodification.
Fortunately,thehobby3Dprintingcommunityisverygoodaboutsharinginformationanddesigns.Ifyour3Dprintermodelisfairlypopular,thereisaprettygoodchancethatsomeonehasalreadydoneall
ofthatworkforyou.Withalittlesearchingandsomeluck,it’sentirelypossiblethatyou’llbeabletofindthemodelsyouneedtoprint,alongwithinformationonthecontrolboardandfirmware.
Butevenifthatinformationisavailable,youneedtobeverycomfortablewithmodifyingyourprinter.Youneedtotakethingsapartandputthembacktogether,rewirethe
controlboardandextruders,andsoon.Addingextrudersdefinitelyisn’tajobforthefaintofheart.
ExtendingAxesWhileI’monthetopicofdifficultmodifications,let’sgoaheadandtalkabout
extendingyourprinter’saxes.Itshouldbereadilyapparentwhythisisadesirablemodification:itmakesyourprintarealarger.Whowouldn’twanttheoptionofprintingbiggerobjects?
Onthesurface,thisseemslikearelativelysimplejob:justgetsomelongersmoothrodsandalargerbuildplatform.Andinsomecases,itisthatsimple.However,it
oftenturnsintomuchmorethanthat.
Thoselongersmoothrodsmayforceyoutomodifytheframetofitthem.Ifthey’reespeciallylong,theymaydroop,whichmeansyou’llneedtogetthickerrods.Thickerrodswillrequirenewmountsandbearings.Theadditionalweightmaymeanyou’llhavetoupgradethesteppermotorsandpossibly
eventhecontrolboardandpowersupply.
Asyoucansee,thisoftenresultsinacascadingeffect.Someprinters(likePrintrbots)canhavetheiraxesextendedeasilyandinexpensivelybecauseofthewaythey’redesigned.ThereareevenkitsavailableforsomePrintrbotmodelstodojustthat.Otherprinters(especiallythosewithfully
boxedframes)willrequirealotmorework.
Asusual,youshouldalwaysstartbylookingatwhatotherpeoplehavedone.Ifothershavebeenabletosuccessfullyupgradetheirprinterswithextendedaxes,lookathowtheydidit.Ifnooneelsehasdoneit,that’sabadsign.Insomecases,itmaynotevenbepracticalorevenpossibletodo.Incases
likethat,it’sbettertojustpurchasealargerprinter.
Converting toa PCB MillEarlierinthisbook,IspentafairamountoftalkingaboutwhatCNCmillsdo.Ifyourecall,CNCmillsmakepartsbycuttingintoablockof
material.Aprintedcircuitboard(PCB)millisbasicallyjustatypeofCNCmillthat’sdesignedtocuttracesoutofstandardPCBsheetsforelectronicsprojects.
HOT TIPMany people convert
their CNC mills into 3Dprinters, but going the otherway doesn’t usually work aswell. The components usedto build 3D printers simply
aren’t as robust as thoseused for CNC mills. Thismeans a 3D printerconverted into a CNC millusually won’t have thepower or rigidity to millanything but very softmaterials (like plastic,machinable wax, and wood).
BeingabletomakePCBsathomeisaprettybigdealforelectronicshobbyists,makingtheconversionfrom3D
printertoPCBmillideal.Soifyou’reinterestedinmakingPCBs,convertingyour3Dprintercanbeaworthwhilesolution.
Convertinga3DprinterintoaPCBmillisverysimilartoconvertingitintoaCNCmillsincePCBmillsandCNCmillsareverysimilar.ButtheconversiontoamillstrictlyforPCBuseisusuallyalittlebiteasier.PCBmillsjust
needtobeabletocutthroughthethinsheetofcopperonablankPCB,whichdoesn’trequirealotofforce.
ThelowpowerrequirementsofPCBmillsmeanthey’reeasiertoconverta3Dprinterinto.Thespindledoesn’thavetobehighpower(anormalrotarytoolwillusuallywork),andtheframedoesn’tneedtobeincrediblyrigid.Overall,it’samuchcheaperandeasier
conversion.
TheeasiestwaytoaccomplishthisistodesignaDremelmountforyour3Dprinter.Ideally,you’llreplacetheextrudermountwiththeDremelmount.That’sallthephysicalmodificationthatisreallyneededfortheconversion.ADremel(orotherrotarytool)hasallofthepowerneededforPCBmilling.
Alterationsfor LaserCuttingMaybeyou’rethinkingtoyourself“Millingissotwentiethcentury;Iwantsomethingmorefuturistic!”Well,ifthat’swhatyou’rethinking,Ihaveatreatforyou:lasers!That’sright,you
canevenaddlaserstoyour3Dprinter.
Lasercuttingisactuallyafairlymaturemanufacturingprocessatthispointandhasbeenaroundforquitesometime.Thebasicprocessissimple:aflatsheetofmaterialislaidoutandahigh-poweredlaserburnsthroughittocreateflatparts.Manypartsarecreatedthisway,andit’sespecially
popularforflatpartsmadefromwood,acrylic,andvariousmetals.
Alasercutteronlyneedstomoveintwoaxes,soa3Dprinteriseasilycapableofthenecessarymovements.Theconversionismostlyamatterofslappingalaseronwheretheextruderwouldgoandreplacingthebedwithaplatformdesignedforlasercutting.Theplatformcanbe
assimpleasatraywithwaterinit,justtokeepthelaserfromdamagingwhateverisbelowthematerialbeingcut.
ThephysicalmodificationswouldbeverysimilartothoseneededforPCBmilling.Justremovetheextrudermountandreplaceitwithamountwhichholdsthecuttinglaser.Theplatformbelowneedstobecapableofreflectingthelaser,sothatit
doesn’tcutthrough.
Butbeforeyoustartdaydreamingaboutopeningametalfabricationshop,youshouldbeawareoftherequirementsforthelaser.Cuttingthroughmetalrequiresavery,verypowerfullaser.Thoselasersareexpensive,andsoistheequipmenttoadequatelypowerit.
However,someother
materialscanbecutwithrelativelyinexpensivelasers.Acrylic,forexample,doesn’trequireaparticularhigh-poweredlaser.Thisismostlyduetohowwellitabsorbstheenergyfromthelaser(asopposedtometals,whichreflectalotoftheenergy).Therefore,it’spossibletoconvertyour3Dprinterintoalasercuttercapableofcutting1⁄4-inch-thickacrylicforjustafewhundreddollars.
HOT TIPIf you’re interested in
converting your 3D printer toa laser cutter, be sure toresearch what kind of laseris needed for the materialsyou’d like to cut. Differentmaterials (and thicknesses)all require lasers of varyingpower. Some materials canbe cut with relatively low-powered lasers, while othersrequire very high-poweredlasers.
Finding PartsFormostofthesemodifications,you’llneedtobeabletosourcethenecessaryparts.Findingthespecificpartsyouneedisn’talwayseasy,butwiththepoweroftheinternet,youshouldn’thavetoomuchtrouble.Thesedays,therearemanywebsitesselling3Dprinterparts,andasimple
Googlesearchwillhelpyoufindaplethoraofthem.However,thefollowingaresomelinkstogetyoustarted:
McMaster-Carr(mcmaster.com):Thisisagreatresourceforallkindsofpartsandcomponents.Theyhaveanenormousselectionofmaterials,fasteners,andallkindsofmachinerycomponents.They’reverypopularintheengineering
world,becausetheirselectionisjustsocomprehensive.
eBay(ebay.com):Youcanfindallsortsof3Dprinterpartsthroughthisauctionandshoppingsite.ThisisespeciallytrueforinexpensivepartscomingdirectlyfromChina.Youwouldbehardpressedtofindbetterpricesanywhereelse,thoughyou’llhavetobepatientifyourpartsarebeing
shippedfromoverseas.
Thingiverse(thingiverse.com):Thisiscurrentlythelargestrepositoryof3D-printablemodels.Asidefromallofthenormalknickknacksanddecorativeitemstoprint,you’llalsofindalotofmodelsforupgrading3Dprinters.Thereisaverygoodchanceyou’llfindahandfulofupgradesforyourprinter
thatpeoplehavealreadymodeledandtestedhere.
The Least YouNeed to Know
Therearemanymodificationsyoucanmaketoupgradeyour3Dprinter,someofwhicharemoredifficultandexpensivethanothers.
Addingaheatedbedallows
youtousematerialsbeyondPLA,makingitapopularmodification.
Withmultipleextruders,youcanprintinmultiplecolors,indifferentmaterials,orwithadedicatedsupportmaterial.
McMaster-CarrandeBayarebothgoodresourcesforfinding3Dprinterpartsonline.Thingiverseisthelargestonlinerepositoryofprintable3Dmodels.Youcanoftenfindmodelsthereforupgradingyourprinter.
APPENDIX
A
GlossaryABSAcronymforacrylonitrilebutadienestyrene,atypeofthermoplasticcommonlyusedfor3Dprinterfilament.Itis
strongbutpronetowarpingandcrackingduringprinting.
ABSjuiceAlsocalledABSglue,asolutionofABSplasticdissolvedinacetone.Itmakesaverystickysubstancethatcanbeusedasasurfacetreatmentontheprintbedtoimproveadhesion.
acetoneAcommonhouseholdandindustrialsolvent.Acetonebreaksdownstyrene,whichallowsitto
dissolveABS.ItcanbeusedforsmoothingABSprintsandformakingABSjuice.
additivemanufacturingTheprocessusedbyall3Dprinters,inwhichapartiscreatedbyslowlyaddinglayerafterlayerofmaterial.
ArduinoAnopen-sourceplatformfordevelopingandprototypingelectronics.Arduinomodelsaregenerallysmallcircuitboardswithout
inputsandoutputsforcontrollingvariouselectronics.TheArduinoMegaisusedbytheRAMPScontrolboardfor3Dprinting.
BasicInput/OutputSystem(BIOS)Thefirmwareinterfaceusedonmostcomputers.It’sthefirstthingtoloadassoonasyourcomputerstartsupandcontrolshowtheoperatingsystem(Windows,for
example)isbooted.
borosilicateAlsoknownasPyrex(oneofitstradenames),atypeofglassthatisformulatedtoreducethermalexpansion.Becauseit’smuchlesspronetothermalexpansionthannormalglass,it’satamuchlowerriskofthermalshock.Thermalshockcancracktraditionalglassifit’squicklyheatedorcooledunevenly,aproblem
thatborosilicatedoesn’texperience.
BowdenAgeneralcategoryofcoldendwherethefilamentisfedfromastationarylocationthroughafeedtubeandintothehotend.
calipersAcommonmeasurementtoolusedinawiderangeoffieldsandindustries.Theycomeinbothanaloganddigitalvarieties
andareusedtomeasurelengths,distances,anddepths.Calipersarecapableofveryhighprecisionandcommonlycomein6-to12-inchsizes(thoughlargerandsmalleronesexist).
CartesianAnadjectiveusedtodescribethingsrelatedtoRenéDescartes,whowasaFrenchmathematicianandphilosopher.Hismanycontributionstomathematics
werethereasonfortheCartesiancoordinatesystembeingnamedforhim(thoughhewasn’tsolelyresponsibleforitsdevelopment).Inthecontextof3Dprinting,itisawayofdefiningpointsin3DspacebytheirX,Y,andZcoordinates.
chamferAsimplebevelededgethatconnectstwosurfaces.Ifthesurfacesmeetat90degrees,astandard
chamferwillcutacrossat45degreesforsymmetry.However,achamferdoesnothavetobesymmetricalandcancutacrossatotheranglesaswell.
coldendThepartoftheextruderassemblythathasasteppermotoranddrivesystemtofeedthefilamentintothehotend.
computer-aideddesign(CAD)Theprocessof
designingpartsusingcomputersoftware(eitherin2Dor3D).Italsoreferstothesoftwareusedtoaccomplishthat.
computer-aidedmanufacturing(CAM)Atermusedtodescribemanufacturingprocessesthatarecontrolledbyacomputer(generallyCNCmills).Italsoreferstothesoftwareusedbythecomputersforcontrolling
themachinery.
computernumericalcontrol(CNC)Awayofcontrollingmachinetoolsusingacomputer,oftenusedforcomputer-controlledmillingmachines.
controlboardThebrainofthe3Dprinter,thecontrolboardisresponsibleforhandlingandprocessingalloftheinputsandoutputsontheprinter.
couplerAmechanicalfastenerusedtoconnecttheleadscrewsonthedrivesystemtotheshaftofthesteppermotor.
DelrinAtradenameforatypeoflow-frictionplastic.
digitallightprocessing(DLP)Oneofmany3Dprintingprocesses,DLPusesprojectedlighttocurephotopolymerresininlayers.
directdriveAtypeofextruderthatdoesn’tuseagearreductionsystem.Becauseoftherelativelylowtorque,directdrivecoldendsaregenerallyonlysuitablefor1.75mmfilament.
directfeedAcategoryofcoldendwherethedrivesystemislocateddirectlyabovethehotend,sofilamentisfeddirectlyfromthecoldendintothehotend.
draftingTheprocessofcreatingtechnicaldrawingsofpartsandassemblies.Apersonwhodoesthisisadrafter(ordraftsmanordraughtsman).Traditionally,thiswasdonewithapencilandpaper,butitisnowdonealmostexclusivelywithCADsoftware.
enclosureAcasethatsurroundsthe3Dprintertokeephotairinandcolddrafts
out.Enclosurescansignificantlyreducewarpingandcrackingonprintedparts.
endstopAswitchattheendofeachofthe3Dprinter’saxesthattellsthecontrolboardwheneachaxisisatitslimit.
extrusionTheprocessusedbyFFF3Dprinterstomeltplasticanddeposititbysqueezingthemoltenplasticthroughanozzle.
filamentThematerialusedbyFFF3Dprinters,whichcomesintheformofalongstrandofplasticandisgenerallywoundonaspool.
firmwareTheprogramthatrunsonthecontrolboardforcontrollingthe3Dprinter.
flatnessOneofmanytermsusedinengineeringtospecifygeometrictolerances.Inthecaseof3Dprinting,itdescribeshowflatasurface
is.
flexiblefilamentAnumbrellatermforanyfilamentmaterialthatisflexible,rubbery,andsquishy.Thiscanbeusedasanalternativetothehardandrigidplasticthatismorecommonlyusedfor3Dprinting.Theexactcompositiondiffersdependingonthemanufacturer,butthe
resultingmaterialisfairlysimilarwithallofthem.
fusedfilamentfabrication(FFF)Alsocalledfuseddepositionmodeling(FDM),the3Dprintingprocessusedbyalmostallconsumer3Dprinters.
G-codeAprogramminglanguagethat3Dprintersandothercomputer-controlledmachinetoolscanuseforinstructions.TheG-codeis
whatisusedtogivemost3Dprintersthecommandstheyfollowtoproduceparts.
greensandAspeciallyformulatedmaterialusedforsandcasting.Sandcastingisusedtoproducemetalpartsbypouringmoltenmetalintoamoldmadeofsand.Themoldisnormallyproducedbyformingitaroundapositivemasterpart;however,3Dprintingthemoldremovesthe
needtofirstcreateamasterpart.
HalleffectDiscoveredbyEdwinHallin1879,referstothetendencyforvoltageinacircuittochangewhenexposedtomagnetism.Itcanbeharnessedtocreateproximitysensorsandissometimesusedforendstopsandprobes.
heatedbedAtypeof3Dprintingbuildplatformthatis
electricallyheatedinordertoaidadhesionandreducewarping.
heatedbuildchamberSimilartoanenclosure,exceptitisactivelyheated.Heatedbuildchamberscanofteneliminatewarpingandcrackingentirely.
heatingelementAsimpleelectricalresistance-basedheatingdeviceusuallyusedtoheatupthehotend.
HIPSAcronymforhigh-impactpolystyrene,atypeofplasticthatcanbeusedassupportmaterialfor3Dprinting.Itdissolvesinlimonene,soitcanberemovedchemicallytoavoiddamagetotheprintedpart.
hostsoftwareThesoftwarethatrunsonyourcomputerandconnectsyourcomputertothe3Dprinter.Itcanbeusedtomanuallycontrolthe
printer,aswellastosendfilestobeprinted.
hotendThepartoftheextruderassemblythatheatsandmeltsthefilamentthatisfedbytheextruderassembly.Asfilamentispushedintothehotend,aheatingelementheatsthehotend.Thetemperatureishotenoughtoalmostinstantlymelttheplasticintoaveryviscousfluid,whichisthensqueezed
outofthenozzleanddepositedontheprintbed.
hypotenuseThelongestsideofaright-angledtriangle.Itisalwaysthesidewhoseendpointdoesn’ttouchtherightangle.
intellectualpropertyAnyideathatislegallyprotected.Providinglegalprotectionforintangiblethingslikeideasisacomplicatedmatter,andthelawsvaryfromcountryto
country.ButintheUnitedStates,intellectualpropertylikeinventions,music,copywriting,patents,andsoonarelegallyprotectedproperty.
layerheightHowthickeachindividuallayeris.Theheightisinverselyproportionaltobothqualityandprinttime,sothethinnereachlayeris,thelongeritwilltaketoprintandthebetterthequalitywillbe.
LCDcontrollerAdevicethatconnectstothecontrolboardandletsyoucontrolthe3Dprinterwithouthavingacomputerattached.
leadscrewAprecision-machinedcomponentfortranslatingrotarymotionintolinearmotion.
mechanicaladvantageTheamplificationofforcewiththeuseofatoolormechanicalsystem.Thisis
usuallyachievedbytradingmovementdistanceforforce.Aleveristhemostbasicexampleofthis,becauseifonesideofthefulcrum(pivotpoint)istwiceaslongastheother,itwilldoubletheforceexerted(thoughitwillalsodoublethedistanceitneedstobepushed).Thissamebasicconceptisappliedinavastarrayofmachinesusingthingslikegears,pulleys,screws,andsoon.
MultiJetPrinting(MJP)A3Dprintingprocessthatusesmultiplenozzlestospraybinderontopowder.
nozzleThesmallopeningattheendofthehotendthatdetermineshowthicktheextrudedfilamentis.
nylonAtypeofplasticthatisnoteworthyforitsverylowcoefficientoffriction.Itcanbefoundinfilamentformfor3Dprinting.
opensourceAphilosophyandusagerightssystemthatallowsinformationtobesharedfreely.
parametricA3DmodelingsystemusedbyCADsoftwarethatdefinesthemodelbyaseriesofparameterswhichcanbemodified.
PETAcronymforpolyethyleneterephthalate,atypeofplasticthatcanbe
usedasa3Dprintingsurfaceinfilmformorasa3Dprintingmaterialinfilamentform.
photopolymerresinAtypeofliquidresinthatsolidifiesintoplasticwhenexposedtolight(usuallyintheultravioletspectrum).Manufacturerscanproducetheresininmanyvarieties,withdifferentmechanicalandchemicalproperties.
pitchThedistancefromonethreadtothenext.Thisiswhatdetermineshowfarthescrewandnutwillmove(relativetoeach)withonefullrotation.Forexample,anM8screwhasastandardpitchof1.25mm.SoifyouhavealeadscrewwithanM8thread,everyfullrotationoftheleadscrewwillmovethenut1.25mm.
polycarbonateAverystrong
plasticthatcanbe3Dprinted.Thisisthetypeofplasticthatbulletproofwindowsaremadefrom.
polyimidefilmOftenreferredtobyitstradenameKapton,afilmthatcanbeusedasa3Dprintingsurfacetoimproveadhesion.Itcanalsobeusedasatapeinveryhigh-temperatureapplications,suchasonthehotend.
powderbedprintingAnytypeof3Dprintingprocessthatappliesaliquidbindertopowder.
printfanAsmallfanthatcoolstheextrudedplasticafterithasbeendeposited.
rapidprototypingAtermthatisoftenusedsynonymouslywith3Dprinting.
RepRapThiscanrefertothe
RepRapproject,whichdevelopsopen-source3Dprinters,aswellasthe3Dprintersthemselves.
reverseengineeringTheprocessofdeterminingthefunctionand/ordesignofaman-madeobjectorsystem.Thiscanbeanythingfromreverseengineeringsoftwaretocomplicatedmechanicalsystems.
scaleThesizeofapartin
relationtoitsphysicalreal-worldcounterpart.Itisoftenusedtorepresentsomethinglarge(likeabuilding)atamanageablesize.
selectivelasersintering(SLS)A3Dprintingprocessthatusesalasertoessentiallymeltapowderintoasolidpiece.Thisprocesscanbeusedfor3Dprintingmetalparts.
shieldInthecontextof
Arduinos,acircuitboarddesignedtobeattachedtotheArduinoboard.ShieldsaregenerallyusedtoexpandthecapabilitiesofArduinosbyaddingeithermoreconnectionsorsensors.Theyareusuallydesignedforaspecificapplication(likeGPStrackingortointerfacewithanotherdevice),althoughplentyofgeneral-useshieldsexist.
slicingsoftwareThe3Dprintingsoftwarethattakesa3Dmodelandconvertsitintoaseriesofinstructionsforthe3Dprinter.
smoothrodAcylindricalmetalrodusedin3Dprintersforlinearmotion.
square-cubelawDescribesthemathematicalrelationshipbetweenareaandvolume.Itsrelevanceto3Dprintingisthewaythatvolume(and
thereforeprinttime)increasesexponentiallywithsize.Forexample,acube10mmtoasidehasavolumeof1,000mm3.Doublingthedimensionsofthecubeto20mmtoasideresultsinavolumeof8,000mm3.Becausethelargercubeis8timesthevolume,itwilltake8timeslongertoprintthanthesmallercube.
steppermotorAtypeof
electricmotorcommonlyusedfor3Dprintersbecauseitsrotationcanbeverypreciselycontrolled.
stereolithographyTheveryfirst3Dprintingprocess,thisusesafocusedUVlasertocurephotopolymerresin.
STLAfileformatusedtostore3Dmodels.Thisfileformatisusedbyalmostall3Dprintingsoftware,aswellasCAMsoftware.
surfacefinishThequality(generallysmoothness)ofthesurfaceofaprintedpart.
tangentReferstoalinethattouchesacurveatasinglepointandcontinuesstraightonfromthatpoint.Theeasiestwaytovisualizethisistopictureacircle.Atangentlinetouchingthefar-rightsideofthecirclewillcontinueonvertically(up,down,orboth),touchingjust
asinglepointofthecircle.Theactualmathematicsofdefiningatangentlinearefairlycomplicated,butluckilyCADsoftwarehandlesallofthat—youonlyneedtobeconcernedwiththepracticaleffect.
thermistorAnelectroniccomponentthatchangesresistancebasedonheat.It’susuallyusedtomonitorthetemperatureofthehotend
andheatedbed.
thermocoupleAtypeoftemperature-measuringdeviceusedinawiderangeofindustries.It’sinexpensiveanddoesn’trequireapowersource,whichmakesitidealforsomeapplications.However,thermocouplesaren’tveryaccurate,whichgenerallymakesthemunsuitableforusein3Dprinterhotends.
threadedrodAtypeoffastenerthatisbasicallyalongboltwithoutaheadattheend.Athreadedrodisoftenusedinplaceofleadscrewson3Dprinters.
unitsTheunitofmeasurementusedin3Dmodelingandprinting.Thisspecifieswhatisusedforthecoordinates—forinstance,millimetersorinches.
ZheightThedistance
betweenthetipofthenozzleandtheprintbed.Thisisadjustableandisimportantforadhesion.
APPENDIX
B
ResourcesIfyou’vefinishedreadingthisbookandyou’relookingformorematerial,orifyoujustneedsomehelpforyourspecific3Dprinter,thisisthe
placetolook.ThefollowingaresomeonlinecommunityresourcesI’vecompiledthatmaybehelpfultoyou.
GeneralResourcesTheseareonlineresourcesthatshouldbeapplicabletojustabouteveryconsumer3D
printer.Thesewebsitescangiveyouinformationontroubleshooting,printermodifications,andprintingingeneral.
3DPrintingSubreddit(reddit.com/r/3Dprinting/):Ifyou’refamiliarwithReddit,besuretocheckoutthissubreddit.It’sthemostactive3Dprintingsubredditandhasmanyknowledgeableusers.
RepRap(reprap.org):This
community-editedresourceisfullofinformationonRepRapandRepRap-derived3Dprinters.Italsocontainsalothelpfulinformationonvarious3Dprintercomponentsthatareusedinallconsumer3Dprinters.
RepRapForums(forums.reprap.org):ThisisanotherRepRapcommunity,butbecauseit’saforum,youcanaskquestionsandget
helpfromotherforummembers.Beforeaskingquestions,besuretousethesearchfunctiontoseeifyourquestionshavealreadybeenanswered.
RepRapSubreddit(reddit.com/r/reprap/):AnotherRedditcommunity,thisoneisspecificallyfordiscussionsaboutRepRap3Dprinters(andtheirderivatives).
Printer-SpecificResourcesThisisalistofwebsitesdedicatedtospecific3Dprintermodelsorbrands.Ifyouneedin-depthinformationonyourparticular3Dprinter,thesearesomewebsitestocheck.
DeezmakerBukobotForums(forum.bukobot.com)
FlashForgeKnowledgeBase(http://www.flashforge-usa.com/support/)
LulzBotForums(forum.lulzbot.com)
MakerBotCommunityLinks(makerbot.com/blog/)MakerBotSubreddit(reddit.com/r/makerbot/)
PrintrbotSubreddit(reddit.com/r/printrbot/)
PrintrbotTalkForums(printrbottalk.com)
SeeMeCNCForums(forum.seemecnc.com)
SolidoodleForums(soliforum.com)
SolidoodleSubreddit(reddit.com/r/solidoodle/)
UltimakerForums
(umforum.ultimaker.com)
UltimakerSubreddit(reddit.com/r/ultimaker/)
MiscellaneousResourcesHereyou’llfindashortlistof
websitesrelatedto3Dprinting,butnotdirectly.Thesewillbegoodforfurtherreadingandresearchforyour3Dprintingprojects.
Instructables(instructables.com):ThiswebsitehasdetailedinstructionsformanykindsofDIYprojects.Alotofthesetakeadvantageof3Dprinting,andthiscanbeagoodplacetofindideasfor
3Dprintingprojects.
Make:(makezine.com):TheonlinewebsiteforMake:magazine,whichisapublicationformakersandtinkerers.ThesamecompanyorganizesMakerFaires,whicharegreatlocaleventswithlotsof3Dprintingboothsanddisplays.
MakerBotThingiverse(thingiverse.com):Thisis,byfar,thelargestandmost
active3Dmodelrepositorythatisspecificallyfor3Dprinting.Asauser,youcandownload3Dmodels,freeofcharge,toprintonany3Dprinter.Youcanalsouploadyourownmodelstosharewithothers.
SerialHobbyism(serialhobbyism.com):Thisismypersonalwebsite,whereIpostarticlesonvarioushobbies(including3D
printing).Ifyoustillwanttoreadmorefrommeafterthisbook,besuretocheckitout!
APPENDIX
C
FurtherUses of 3D
PrintingYou’vereadthroughthis
entirebookandevenmanagedtoreachthefinalappendix!Obviously,youjustcan’tgetenoughof3Dprinting.Luckily,therearealotofusesfor3DprintingIhaven’tgoneintoyet.Someoftheserequiremorethanjustaregular3Dprinter,whileothersareverynewandexperimentalwaysofusinga3Dprinter.Whateverthecase,mostofthesewillalsorequireadditionalresearchon
yourpart.Butthisshouldgiveyouanideaofsomemorethingsyoucandowithyour3Dprinternowandpotentiallyinthefuture.
Your 3DPrinter as anIntermediary
Process ToolOnewaytotakeadvantageofyour3Dprinteristouseitasanintermediaryforothercreativeprocesses.Thinkofitlikehowyouuseamixerbeforeusingtheovenwhenyoubakeacake.The3Dprinterbecomesjustonetoolintheprocessinsteadofdoingeverything.Usingthisapproach,youcangetaround
thelimitationsof3Dprinting,especiallywhenitcomestomaterialoptionsandproducinglargequantitiesofparts.
Investment CastingInvestmentcastingisanextremelyoldmanufacturingtechnique.It’stheprocessofmakingapart,surroundingitwithamold,andthenpouring
moltenmetalintothemoldtoreproducethepart.Thereasonit’scalledinvestmentcastingisbecausetheoriginalpartislostduringtheprocessandthemoldcannotbereused.
Traditionally,investmentcastingwasdonewithawaxoriginalpart.Thewaxwaseasytoworkwith,meltedeasily,andwascheap,allowingapersontomakean
intricatemetalpartbyfirstworkingwithwax.Investmentcastingwas(andis)verypopularformakingjewelry.
Butastonishingly,3Dprintersarealmostperfectforthisprocessaswell.YoucandesignapartinCAD,3DprintitinPLA,andusethatprintedpartforinvestmentcasting.ThemeltingpointofPLAislowenoughthatit’s
suitableforinvestmentcasting.
Withthisprocess,youdon’tneedawildlyexpensiveSLS3Dprintertomakemetalparts.Instead,youcanjustuseyourinexpensivehobbyprintertoprintPLAparts,andthenuseinvestmentcastingtomakemetalparts.Thisisamethodthathasbeenproventoworkverywellandisactuallyrelatively
inexpensive.
Sowhatdoyouneedtoactuallydothis?Well,firstyouneedawaytomeltthemetal,whichisajobhandledbyafoundry.Aluminumfoundriescanbemadeathomeforlessthan$100.You’llalsoneedahandfulofbasictoolsandsafetyequipmentforhandlingthemoltenmetal.Andfinally,you’llneedsomecastingsand
formakingthemoldsthemselves.
Allinall,youcanprettyeasilygetsetupforinvestmentcastingforjustacouplehundreddollars.Homemetalfoundriesareusuallyonlycapableofhandlingaluminum(whichhasarelativelylowmeltingpoint),butthat’sgoodenoughformosthobbyists.
Awholebookcouldbe
writtenoninvestmentcastingalone,butthebasicsareeasyenoughtounderstand:
Onceyou’veprintedapartinPLA,fillacontainerabouthalfwayfullwithyourcastingsand.Therearemanyformulasinuseforthesand,butit’sgenerallynormalsandmixedwithsomesortofbinder,likeplaster.
Pushhalfthepartintothesand,makingsureallofthecrevicesofthepartarefilled
in.
Filltherestofthecontainerwithsand,withasprue(whichformsachannel)forpouringthemetalandanothertoventtheairandgasesasthemetalispoured.
Oncethecastingsandhashadtimetoset(thetimeframewillvarydramaticallydependingonthesandformula),removethehardenedblockofsandfromtheformingcontainer.
Usingthefoundry,meltthemetal(usuallyaluminumforhobbycasting)inacrucible.Onceit’smolten,itcanbepouredintotheopeningformedbythesprue.Asit’spouredin,themoltenmetalwillmeltawaytheoriginalPLApart.
Afterthemetalhascooled,theblockofsandcanbebrokenapart,andthemetalpartcanberemovedforfinishing.
Itmaytakesomepractice,butsoonyou’llbeabletomakeyourown3Dmetalpartsathome!
Mold Making andResin Casting3Dprintingisgreatformakingafewparts,butwhatifyouwanttomakemanycopiesofthesamepart?Investmentcastingdestroys
theoriginalpartandthemold,soit’snotagoodoptionifyouwantmultiplecopies.Thisiswheremoldmakingandresincastingcomein.Theyallowyoutomakemanycopiesofapartbysimplypouringmolds.Thisisamoretime-andcost-effectivemethodofcreatingduplicatepartsthansimply3Dprintingthem.
Thefirstwaytogoaboutthis
isto3Dprintthemolditself(whichisthenegative).Thiswillrequireyoutoeitherusemold-makingtoolsinCADormanuallymodelthemoldinCAD.Withamodelofthemold,youcansimply3Dprintitlikeanyotherpart.
Aone-piecemoldformakingachocolatebunny.
Onceyouhaveyourmold,youcanusecommonhobbycastingmaterialstomakeyourparts.However,notallmaterialswillbesuitable,
becausesomewillsticktothemold.Butmanymaterials(suchassilicone)canbeused.
Allyouhavetodoispourtheliquidmaterialintothemoldandwaitforittosetandcure.Dependingonthematerial,thiscouldtakeanywherefromafewminutestoacoupleofdays.Onceit’scured,youcanjustpullitoutofthemoldandstartanew
part.
Theotherwayofcastingaddsanextrastepbuthasanumberofbenefits.Forthisprocess(oftencalledresincasting),youprintanormalpartonyour3Dprinterexactlyasyounormallywould.Youthenuseaflexiblesiliconemold-makingrubbertomakeamoldaroundtheprintedpart(thepositive).Afterthesiliconehascured,
youcanremovetheoriginalpartandbegincastingnewpartsbypouringresinintothesiliconemold.
Thebenefitsoftheresincastingmethodaretwofold:youcanmakemanymoldsfromasingleprintedpartwhichcanbeusedsimultaneously,andyourfinalpartscanbemadefromavarietyofmaterials.Withtheresincastingmethod,you
canmakeyourfinalpartsfrommaterialslikepolyurethane,whichisincrediblystrong—andmuchstrongerthantheoriginalprintedpart.
Using YourPrinter forGood
Butmaybeyou’renotjustlookingforanotherwayofmakingparts.Maybeyouwanttodoalittlemore,andmaybeyou’reevenfeelingphilanthropic.Asluckwouldhaveit,3Dprintingcanhelpwiththat,too!
Charity WorkOneofthemostexcitingthings3Dprintersarebeing
usedforrightnowischaritywork.Oneuseinparticularhasgrabbedtheattentionofmanypeople:3Dprintingprosthetics.
Traditionally,prostheticshavebeenveryutilitarianandratherunwieldy.They’reexpensiveandtendtobeill-fittinganddifficulttouse.Customprostheticshavealwaysbeenmuchbetter,butthey’reevenmoreexpensive
andaren’tusuallycoveredbymedicalinsurance.
That’swhere3Dprintinghascomein.Underthedirectionoforganizationslikee-NABLE(enablingthefuture.org),3Dprinterownershavebeenabletogiveahandtothoseinneed—literally.Peoplewithaccessto3Dprinterscan3Dprintprosthetichandsandgivethemtothepeoplewho
needthem.
Allofthepartsneededforaprosthetichand,readytoprint.
Ican’toverstatehowrevolutionarythisis.Theprostheticsthemselvesarerapidlybecomingmoreandmoreadvancedasthey’re
developedfurther.Theycanbecustomizedtofittheuserperfectly.And,perhapsbestofall,they’reveryinexpensiveto3Dprint.
Thishasallowedthosewhohavelostlimbstogethigh-qualityprostheticsforfree.Andthoseprostheticsaren’tjunkeither;inmostcases,they’remuchbetterthantheprostheticstheywouldhavereceivedthroughtraditional
avenues.
Perhapsmostimportantly,thee-NABLEprojectishugelybeneficialtochildren.Becausechildrengrowsoquickly,it’sdifficultforthemtogetprostheticsthatfitthemastheygrow.Butnowtheycanreceivenew3Dprintedprostheticsthatfitthemperfectlyastheygetolder.
Soifyouhaveanyinterestingivingback,Ihighly
recommendyoulookintothisproject(andothers).Withjustalittlebitofyourtimeandfewbucksworthoffilament,youcanreallymakeadifferenceinsomeone’slife.
HackerspacesIftheideaofgettinginvolvedinmakingthingswithotherpeopleappealstoyou,considerjoiningalocal
hackerspace(hackerspaces.org)ormakerspaceinyourarea.Hackerspacesarebasicallysmallcommunityworkspaceswherememberscanuseavarietyoftoolsfortheirownpersonalprojects.Theideaisprettysimple:toolsareexpensive,sowhynotsharethem?
MostbigcitiesintheUnitedStateshaveoneormore
hackerspaces,andit’slikelythereisoneinyourarea.Tojoin,youusuallypayamonthlyfeetogainaccesstothehackerspace.Onceyou’reamember,you’llhaveaccesstoawiderangeoftoolslike3Dprinters,CNCmills,lasercutters,welders,carpentrytools,andsoon.
Additionally,thiswillgiveyouaplacetocongregatewithotherlike-minded
people.Youcancollaborateonprojects,gethelpwithchallengingproblems,andtakeclassestoexpandyourskillset.Somehackerspacesarefocusedonparticulartopics(likeelectronicsormetalworking),whileothersaremoregeneralandhavealittlebitofeverything.
Ifyoudojoinahackerspaceandhavea3Dprinter,it’scertainlyworthconsidering
bringingyour3Dprinter.Theydousemembershipduestopurchasetools,buthackerspacesareexpensivetorun.Alotofthetoolsthereareownedbymembersorweredonatedbymembers.Whetheryoudecidedtobringyour3Dprinterornot,hackerspacesandmakerspacesareagreatwaytogetinvolvedwithpeopleinyourcommunity.
PotentialApplicationsfor 3DPrintingSofar,I’vetalkedabout
thingsyoucanuseyour3Dprinterfor.Butmaybeyou’reinterestedinlearningaboutsomeexperimentalusesof3Dprintingcurrentlyindevelopment.Ifso,therearemanyinterestingapplicationsfor3Dprintingthatarecurrentlybeingexplored.
Fornow,theseusesof3Dprintingarestillexperimentalandunderdevelopment,butthepossibilitiesforimproving
people’slivesareveryinteresting.They’restillverynew,butasthesetechnologiesmature,you’llstarttoseehowtheycantrulyaffectpeople’slivesaroundtheworld.
Printing FoodFFFisuniqueamong3Dprintingtechnologies,becausethesamebasic
conceptthatallowsanFFFprintertoextrudermoltenplasticcanalsoworkforanyothermaterialthatcanbeliquefiedandthensolidified.Ifasubstancecanbeliquefied,squeezedoutofanozzle,andthensolidified,itcantheoreticallybe3DprintedusingtheFFFprintingprocess.Thatcanevenincludefood.
Whywouldanyonewantto
3Dprintfood?Rightnow,myimpressionisthatit’smostlyamatterofnovelty.Buttherearesomereasonswhyitcouldbemorethanjustacuriosity.Oneexampleofthisisweddingcakes.Anyonewhohaseverhadtoshopforweddingcakesknowsthatintricatedetailinthedecorationishighlysoughtafter.Thosedecorationsarecarefullycraftedbyhandbythebaker,
whichcanbedifficultandtime-consuming,whichmeansit’sexpensive.
Butwhatifthoseintricatedecorationscouldbe3Dprinted?It’spossibletouseanFFF3Dprintertoextrudeicingontoacakeandtocreatecomplexdecorationswiththeicing.Infact,it’salreadybeendone.Icingisstoredinatubewhichcanbecompressedtosqueezethe
icingthroughanozzle.JustlikewithastandardFFFprinter,theicingcanthenbelayeredtocreate3Ddesigns.
Cakedecorationsarejustoneexampleof3Dprintingfood,andadmittedlyit’snotlikelytochangetheworld.Butwhatif3Dprintingcouldbeusedinanunconventionalwaythatdoeshavethepotentialtochangetheworld?
Creating BuildingsIfyou’veeverseenanewbuildingbeingconstructed,youknowitcantakeweeksormonths.First,afoundationneedstobepoured.Afterthat,aframehastobeconstructed,wallsmustbeadded,aroofneedstobebuilt,sidinghastobeadded,andsoon.It’salengthyandcomplicatedprocess,andalotoflaborisneededforthe
construction.Butwhatifbuildingsthemselvescouldbe3Dprinted?
That’snotonlypossible,butit’salreadybeendone.It’sstillveryexperimental,ofcourse,andismostlybeingdonetotesttheidea.Butitisbeingdone,andtheideahasbeenproven.Theprocessworksbyextrudingconcrete,layerbylayer,toformthestructureofthehouse.
Theideaof3Dprintinghousesorotherbuildingshastremendouspotentialforchangingtheworld.Forone,automatingtheprocessofconstructionmeansthelaborneededisgreatlyreduced.Also,alarge-scale3Dprintercanalsorunalldayandnight,reducingthetimeittakestoconstructabuilding.
Thepossibilitiesarealmostlimitlessforthistechnology.
Stronganddurablehomescanbebuiltquicklyandcheaplywithoutskilledlabor.Bymountingtheconcreteextruderonacrane,thepotentialsizeofthe3Dprintedbuildingisalmostcompletelyunrestricted.Buildingplanscanbeeasilyreused,reducingthetimeandcostofdesigningthem.
Youcanprobablyeasilyimaginetheimplicationsin
third-worldanddevelopingcountries.Long-lastinghomesandbuildingscouldbeconstructedquicklyandefficiently,makingabigdifferenceincountrieswherefamiliescan’taffordhomesconstructedusingtraditionalmeans.
Thepotentialforimprovingthelivingconditionsofpeoplearoundtheworldisfantastic.Butwhatif3D
printingcouldgoevenfurther?Whatifitcouldactuallysavelives?
Making OrgansEventhewealthiestcountriesintheworldstrugglewithprovidingadequatehealthcaretotheircitizens.Onecomplicationinparticularisholdingbackmedicalcare:organtransplants.Two
problemsmakeorgantransplantsespeciallydifficult:findingorgandonorsandrejectionofthetransplantedorgan.
Findinganorgantotransplantisproblematicforobviousreasons:itrequiresadonor.Forsomeorgans,likekidneys,thedonorcanbealive,butmostpeoplearen’teagertopartwiththeirorgans.Forothers—like
hearts,forexample—thedonorhastobedeceased.Inbothcases,it’sdifficulttofindadonor.Evenifadonorisfound,bloodtypeshavetomatchbetweenthedonorandtherecipientofthetransplant(amongotherrequirements).
Afterallofthathasbeendone,it’sstillpossibleforatransplantedorgantoberejectedbytherecipient.Thehumanbodyjustisn’ttoo
acceptingoftissuethatoriginatedinanotherbody.
Luckily,researchersthink3Dprintingcansolvebothoftheseproblems.Theideaisthattissueisharvestedfromthepatient’sownbodyandusedasthematerialto3Dprintaneworgan.Thismeansadonorisn’tneeded,andalsomeansthatthepatient’sbodyislikelytoaccepttheneworgan.This
possibilityaloneisenoughtorevolutionizemedicine,butitdoesn’tstopthere.
Whenpharmaceuticalcompaniestestnewdrugsortreatments,theyneedsomethingtotestthemon.Traditionally,thisisdoneonanimalsorhumanpatients,whichcanberiskyforboth.Butiflivingtissuecanbe3Dprinted,itwouldbepossibletoethicallytestdrugswithout
theriskofharminganyhumansoranimals.Italsomeanstissuecanbeprintedwithaspecificconditionthatthedrugisdesignedtotreat.
Forexample,ifapharmaceuticalcompanywantedtodevelopanewtreatmentforcancer,theycould3Dprinttissuewithcancer.Thatwouldletthemtestthetreatmentonrealhumantissuethathascancer
withoutriskingthewell-beingofanactualcancerpatient.Doneonalargescale,thiscoulddramaticallyreducethetimeittakestodevelopanewdrugwhilesimultaneouslyincreasingtheeffectivenessofthatdrug.
About theAuthorCameronCowardisamechanicaldesignerand3Dprintingenthusiast.Asamechanicaldesigner,hehasextensiveexperiencewithCAD,3Dprinting,CNCmilling,andtraditional
manufacturing.Onhisself-runwebsite,SerialHobbyism(serialhobbyism.com),heuseshisprofessionalandpersonalexperiencetoteachreaderseverythingtheyneedtoknowaboutstartingnewhobbies.Whenhe’snotwriting,CameroncanbefoundworkingonprojectsinhisworkshoporinthemountainsofColorado.