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RhinoCAM Tutorial 1 - The Basics LouisianaStateUniversity CollegeofArtandDesign

DesignShop WrittenbyPaulCallahan

Updated2.9.15

I N T R O D U C T I O N

ThistutorialwaswrittenforstudentsintheCollegeofArtandDesignforusewiththe3axismillthatishousedintheDesignShop-TormachPCNC1100.TheCollegeofArtandDesignowns5licenseofRhinoCAM.WeuseoneintheDesignShoptocheckthetoolpathsbeforetheyareuploadedtothecontrolcomputerthatoperatesthemill.CAD-GIScomputerlabhascomputerswithRhinoCAMinstalledandaccessibleforstudentuse.

TherearemanyprogramsonthemarketthatcanbeusedtogenerateGcodeformillingoperations.ThepurposeofaGcodegeneratoristohelptheuserwritecodethattellstheCNCmilleachmovementnecessarytocuttheirdrawingoutofasolidblockofmaterial.CNCmachinesunderstandalanguagecalledGcode.BeforetheadventofprogramslikeRhinoCAM,Gcodewasallwrittenbyhand.Initssimplestform,Gcodeisasetofcommandsthetellthemachineinformationsuchasspindlespeed,go-tocommandsforthecutterandtoolpathspecificslikestepoverandstepdowndistances.

OneofthemainadvantagesofusingRhinoCAMtogenerateGcodeinsteadofanotherGcodegeneratoristhatitexistsasaplugin,runningsimultaneouslywithRhino,andthereforeusestheRhinoenvironmentforanydrawingornavigationalpurposes.IfyouarefamiliarwithRhinoyoucanseehowthisisanadvantage.Infact,thistutorialas-sumesthatyoualreadyknowthebasicsofRhino.AnothermajoradvantageofRhinoCAMisthatasyoumakeeditstoyourdrawing,thetoolpathsthatyouhavealreadygeneratedwillupdatewithaclickofthemouse.

Forthepurposeofthistutorial,LMB=LeftMouseButton,RMB=RightMouseButton.

M A C H I N E S P E C S A N D R E S T R I C T I O N S

ThemachineyouwillbeusingistheTormachPCNC1100.Ithasstandard3axiscapabilities(X,YandZmovement)andanadditionalfourthaxisrotaryattachment,theAaxis.However,thefourthaxisattachmentwillnotbecoveredinthistutorial.Sizelimitationsareasfollows,Xmovement:16”Ymovement:6”Zmovement:11”.Thisdoesnotmeanyoucancutashapethatis16”x6”x11”.AsitpertainstotheXandYdimensions,youmustfactorinspaceforworkholddownsorfixtures.See,settingupstockonpage4 forspecificdimensions.WhenitcomestotheZsizelimita-tions,youarerestrictedbythelengthofthecutter.IfyouhavequestionsaboutthisaskaDesignShopemployee(eitherMarkorPaul).

S A F E T Y C O N C E R N S

Likeallmachines,themillcanbedangerousifmisused.Thesearerulesthatmustalwaysbefollowedwithnoexceptions.Also,beforeanyoneispermittedtousethemilltheymustbecertifiedtousetheDesignShop.ThisinvolvescompletingtheorientationandpassingtheDesignShoptestandmustbedoneonceperyear.

1.Youmuststaywiththemillandbeinreachoftheemergencyshut-offbuttonatalltimeswhilethemilliscutting Fig.1.

2.Safetyeyewearandearprotectionmustbewornatalltimeswhilethemilliscutting.TheDesignShopprovides eyeandearprotectionforusewhileintheshop.

3.Nothingshouldbehangingordanglingfromyourbodywhilesettinguporoperatingthemill.Thisincludeshair, jewelryandlongsleeves.

4.Neverreachinsidethecuttingareawhilethemillisrunning. 5.TheacrylicshieldmustbeinplaceatalltimesexceptduringsetupFig.2. 6.ClosetoeandheelshoesmustbewornatalltimeswhenintheDesignShop

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L AY O U T A N D W O R K F L O W

Inthistutorialyouwilllearnabasic,commonstrategyforcuttingoutyourshapebycreatingtwotoolpaths,aHorizontalRoughingtoolpathandaParallelFinishingtoolpath.Thepurposeofthesetoolpathsisastheirnamesuggests,HorizontalRoughingusesanendmilltoremovethebulkofthematerialandtheParallelFinishingusesaballmilltorefinetheshapeandbringittoatolerancethatisclosetotheshapethatyouhavedrawninRhino.RhinoCAMofferstheabil-itytocutinmorecomplextoolpathsbutyouarerequiredtolearnthisbasicstrategybeforemovingontomoreadvancedoperations.

IfthecomputeryouareusinghasRhinoCAMinstalledyouwillseetheRhinoCAMdropdownmenuatthetopofyourscreen(Fig.3).ClickonthisandselectMill.TheRhinoCAMwindowswillautomati-callyopen(Fig.4).

ThelayoutinRhinoCAMisrelativelysimple.Therearetwomainwindowswewillbeusing.Thetopwindowcontainstwotabs,thePro-gramtabandtheSimulatetab-(Fig.5).TheSimulatetabiswhereyoucontrolthesimulationsofthetoolpathsafteryougeneratethem,andtheProgramtabiswhereyoudoeverythingelse.Inthebottomwindow(Fig.5)youwillfindafoldercalledtheMachineJobfolderwhichcontainsallofthesettingsforyourspecificjob.WhenyouopenRhinoCAM,theMachineJobfolderalreadyexistsandcontainsallofthedefaultsettings.

BelowtheMachineJobfolderaretogglebuttons(RedBoxinFig.4).Byclickingthemyoucaneitherrevealorhidethetoolpath,thestockandthepart.Thereisalsoanoptiontomakematerialtexturevisible.DONOTdothis,itmaycauseRhinoCAMtocrash.

Fig. 1

Fig. 2

Fig. 3

Fig. 4

Ifyoudonotfollowtheserules,youwillbeaskedtoleaveandDesignShopprivilageswillberestrictedorrevoked.Thisisforyourownsafety.

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1TherearetwoiconsintheMachineJobfolder,the“Machine-3axis”icon,andthe“Post-TormachINCH”icon.Thedefaultset-tingsarecorrectandwewillnotchangethem.However,doublecheckthatyoursettingsarethesameasshowninFigs.6&7.

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Fig. 6 Fig. 7

Fig. 5

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itisalsohowwejustifyandalignourdigitaldrawingwithinourphysicalstock.TheWorkZerocanbeanypointyousetittobe.Aslongasyoucanidentifyitonboththeworkpieceandthedrawing.Inthiscase,IwillsetittobeinthehighestZ,northwestcornerofthepart(notthestock).

1.WhileintheprogramtabLMBMachiningOperations(Fig.8)2.LMBWorkZero(Fig.8)3.LMBSettoPartBox(Fig.9)4.LMBHighestZ(Fig.9)5.LMBNorthWest(Fig.9)6.LMBGenerate

S T O C K S E T- U P Whenyousetupthestock,youaresimplytellingthecom-puterthedimensionsofyourphysicalstock.Thisisimpor-tantbecauseweneedtoaccountforspaceonthestocktoholdittothebedofthemillwitheitherclampsorscrews.1.UndertheMachineJobfolder,double-clickStock2.LMBCopyModelBoundingBox(Fig.10).Thiswillsetthestocktotheextentsofyourpartineachdimension.Fromthis,youwilladdstockbelowthepartandaroundthefoursides,butnottothetop.3.L-add2”tothisvalue(Fig.10)4.W-add1”tothisvalue(Fig.10)5.H-add.15”tothisvalue(Fig.10)6.LMBOK

W O R K Z E R O

TheWorkZeroisaspecificpointyouwilldefineintheCar-tesiancoordinatesystemthatyoucanreferenceinboththedigitalspaceinRhinoCAM,andinthephysicalspaceonthestockthatyouintendtocutyourshapeoutof.TheCNCmillwillreferencethispointforeverymovementitmakesand

Fig. 10

Fig. 8

Fig. 9

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S T O C K & PA RT A L I G N M E N T

Next,wewillalignthepartwithinthestock.1.IntheProgramtab,LMBAlignStock(Fig.11)

2.LMB,AlignStock(Fig.12)2.LMB,Top(Fig.12)3.LMB,Center(Fig.12)4.LMB,OKIfyoudidthiscorrectly,thetopviewinRhinowillshowyourpartcenteredinsidetheyellowstockbox,andfromthefrontviewthepartshouldbeallthewayatthetopofthestock.Theextrathicknessweaddedtothestockshouldbebelowthepart.Youmayalsoneedtotogglethestockvis-ibilityon(Fig.4).IfyourollyourmouseoverthebuttonsinFig.4aboxwillappearthattellsyouwhattheydo.

M A C H I N I N G F E AT U R E S / R E G I O N S TA BThistabgivesyouawaytorestrainthemovementofthecutterintheXandYdirections.RestrainingtheZmove-mentisdoneinanothertab(CutLevels).IfyouclickonSelectDrive/ContainmentRegionsbutton(Fig.14),theHor-izontalRoughingwindowwilldisappearallowingyoutoaccesstotheRhinodrawingenvironment.Thecommandbarwillnowpromptyoutoselectacontainmentregion.Thiscanbeeitheranedgeonyourshape,orapolylinethatyoudrawinyourRhinodrawing.Inthecaseofsamplefileforthistutorial,Idrewaboxaroundmyshapethatwas.3”biggerthanmypartineachdirection.Thisallowsroomforthe.25”cutterstocutaroundtheoutsideperimeterofmyshape.Ifyoudonotsetanymachiningregions,theCNCmillwilllikelycollidewiththeworkpieceholddowns.1.InMachiningFeatures/RegionsTab,LMB,SelectDrive/containmentRegions(Fig.14)2.LMB,selecttheregions(CanbepolylinesoredgesofyourRhinoshape)3.RMB,AsinRhino,rightclickinginthissituationisthesameaspushingEnterT O O L TA B

Fig. 11

Fig. 12 Fig. 13

H O R R I Z O N TA L R O U G H I N G Nowwewillgeneratethefirsttoolpath.1.WhileinProgramtab,LMB,MachiningOperations(Fig.13)2.LMB,3AxisAdvanced(Fig.13)3.LMB,HorizontalRoughing(Fig.13)

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Thisiswhereyouwillsetupthetoolyouwilluseforthehorizontalroughingtoolpath.Asmentionedearlier,youwilluseanendmill.ThetwotypesofcuttersthatweofferintheDesignShopareballmillsandendmills.Thesenamesrefertotheprofileofthecutter.Inthecaseofaballmill,theprofilecutsastraightedgeonitssideandahalfcircleonthetip(Fig.15).Anendmill’sprofileisthesameexceptthatthetipisperfectlyflat(Fig.16).

Collisionscanbeoneofthemostdangerousac-

cidentsthatcanhappenonamill.AcollisionoccurswhenanypartoftheCNCmillcollideswithanythingthatyou,theuser,didnotintendtoforitto.Themostdamagingofthesecanbewhenthecuttercollideswithaworkpieceholddown.Thesearestationaryandmadeofsteel.Ifthishappens,thechancesaregoodthatthecutterwillshatter,sendingpiecesofsteelshrapnelflying.AlloftherulesintheS A F E T Y C O N C E R N S sectiononpage1areinplacetopreventcollisions.Anotherwaytoavoidcollisionsistotakeaccuratemeasurementswheninputtingthedimensionsofthecuttersyouwilluse.IntheDesignShop,weofferasetofdigitalverniercalipers(Fig.17)tohelpyoumeasureaccurately.Ifyouenterthecutterdimensionsaccurately,RhinoCAMwillgenerateGcodethatwillnotcontainanycollisions.

Fig. 15 Fig. 16

Fig. 17

Fig. 14

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TheTooltabispicturedinFig.18.WhenyoufirstopenthistabtheToolsfolderwillbeempty.Toaddthefirsttool,LMBEdit/Create/SelectToolbutton(Fig.18).ThenextwindowyouseeshouldlooklikeFig.19.1.LMB,Endmilliconinupperleft(secondbuttonfromtheleftFig.19)2.Usingcalipers,takemeasurementsfromthecutteryouintendtouseandenterthevaluesinthebottommiddleofwindow.Ifyouarenotsurewhataspecificmeasurementisfor,referencethediagraminthiswindowforanexpla-nation.3.LMB,SaveeditstotoolIfyoudidthiscorrectly,atoolcalledFlatMill1willshowupintheToolsTab.WhileintheToolstab,LMBFlatMill1.

Fig. 19

Fig. 20

Fig. 18

F E E D S & S P E E D S TA B TheexpressionFeeds&Speedsreferstothefeedrate,orrateatwhichthemachinemovesthroughyourmaterial(expressedininches/minute),andthespeedatwhichthespindlespins(expressedinrotations/minute).Therearemanyfactorsthateffectthevaluesyouselectforfeedsandspeeds.Thesefactorsinclude,hardnessofmaterial,stepoverandstepdowndistances,numberofflutesonthecutter,diameterofthecutter,etc.PageX ofthistutorialcon-tainsaguideforselectingfeedrate,spindlespeed,stepoverandstepdown.Inthecaseofthisproject,IamcuttingmyshapeoutoffoamsoIcanbeveryaggressivewiththesevalueswithoutfearofdamag-ingthecutter.1.Setvaluesforfeedsandspeeds(Fig.20)

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Fig. 21 Fig. 22

C L E A R A N C E P L A N E TA B ThissettingtellsthemillthatwhenitretractsfromthematerialitmustdosotoacertainZdistance(whichyouwillset)beforetransferringtoanotherareatocut.1.LMB,StockMaxZ+Dist(Fig.21)2.Setvalueto.25”Thissettingwillensurethatthecutterretracts1/4”abovethethicknessofthestockbeforetransferringtoavoidcollisions.C U T PA R A M E T E R S TA B Inthistabyouwillsetthestepoverdistance.Thisvalueisexpressedasapercentageofthediameterofyourcutter.Inmycase,Iamusinga1/4”endmillandIwantittostepover50%(Fig.22).1.ReferencetheStepover/StepdownguideonpageX foradviceonStepoveramount2.Enterthisvalue(Fig.22)

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Fig. 23

Fig. 24

C U T L E V E L S TA B Youwillchangetwosettingsinthistab,thestepdownamountandthecutlevels.Onthehorizontalroughingpassyourgoalistosafelyremoveasmuchmaterialasyoucanwithoutconcernfortolerance.TolerancebecomesimportantduringtheParallelFinishingpass.

SettingabottominCutLevelsisthewaythatyourestricttheZdepthmovement.Thecutterwillnotvio-latetheZplanethatisparallelwiththepointthatyouselect.1.LMB,%ToolDiameterbutton2.Enter50%(Fig.23)3.LMB,“Bottom”CheckBox

4.LMB,MouseArrowbuttonnextto“Bottom”(Fig.23)5.LMB,ChooseapointatthelowestZaxisofyourRhinodrawing.E N G A G E / R E T R A C T

Thistaballowsyoutospecifyanengagementstrategy.Whenthecutterfirsttouchesthemate-rialyouhavetheoptiontomovethecutterinaspiralorzigzagpatterntoalleviatestressonthetool.1.LMB,Helix(Fig.24)

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M A C H I N I N G F E AT U R E S / R E G I O N S TA BThistabgivesyouawaytorestrainthemovementofthecutterintheXandYdirections.RestrainingtheZmovementisdoneinanothertab(CutLevels).IfyouclickonSelectDrive/ContainmentRegionsbutton(Fig.26),theParallelFinishingwindowwilldisapearallowingyoutoaccesstotheRhinodrawingenvironment.Thecommandbarwillnowpromptyoutoselectacontain-mentregion.Thiscanbeeitheranedgeonyourshape,orapolylinethatyoudrawinyourRhinodrawing.If you do not set any machining regions, the CNC mill will likely collide with the workpiece hold downs.1.InMachiningFeatures/RegionsTab,LMB,SelectDrive/containmentRegions(Fig.26)2.LMB,selecttheregions(CanbepolylinesoredgesofyourRhinoshape)3.RMB.AsinRhino,rightclickinginthissituationisthesameaspushingEnter

Fig. 25

PA R A L L E L F I N I S H I N G Nowwewillgeneratethesecondtoolpath.1.WhileinProgramtab,LMB,MachiningOperations(Fig.25)2.LMB,3AxisAdvanced(Fig.25)3.LMB,ParallelFinishing(Fig.25)

Fig. 26

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T O O L TA B ThisiswhereyouwillsetupthetoolyouwillusefortheParallelFinishingtoolpath.Asmentionedearlier,youwilluseaballmill.ThetwotypesofcuttersthatweofferintheDesignShopareballmillsandendmills.Thesenamesrefertotheprofileofthecutter.Inthecaseofaballmill,theprofileitcutsisastraightedgeonitssideandahalfcircleonthetip(Fig.27).Anendmill’sprofileisthesameexceptthatthetipisperfectlyflat(Fig.28).

Colisionscanbeoneofthemostdangerousaccidentsthathappenonamill.AcolisioncanoccurwhenanypartoftheCNCmillcolideswithanythingthatyou,theuser,didnotintendtoforitto.Themostdamagingofthesecanbewhenthecuttercolideswithaworkpieceholddown.Thesearestationaryandmadeofsteel.Ifthishappens,thechancesaregoodthatthecutterwillshatter,sendingpiecesofsteelschrapnalflying.AlloftherulesintheS A F E T Y C O N C E R N S sectionon

Fig. 27 Fig. 28

Fig. 29

TheTooltabispicturedinFig.30.AtthispointyoushouldalreadyhavetheendmilltoolsavedfromtheHorizontalRoughingtoolpath.Toinputthemeasurementsfortheballmill,LMBEdit/Create/SelectToolbutton(Fig.30).ThenextwindowyouseeshouldlooklikeFig.31.1.LMB,Endmilliconinupperleft(Fig.31)2.Usingcalipers,takemeasurementsfromthecutteryouintendtouseandenterthevaluesinthebottommiddleofwindow.Ifyouarenotsurewhataspecificmeasurementisfor,referencethediagraminthiswindowforanexplanation.3.LMB,SaveeditstotoolIfyoudidthiscorrectly,atoolcalledBallMill1willshowupintheToolsTab(Fig.30).WhileintheToolstab,LMBBallMill1.

Fig. 31Fig. 30

page1areinplacetopreventcolisions.Anotherwaytoavoidcolisionsistotakeaccuratemeasurementswheninputingthedimensionsofthecuttersyouwilluse.IntheDesignShop,weofferasetofdigitalverniercalipers(Fig.29)tohelpyoumeasureaccurately.Ifyouenterthecutterdimensionsaccurate-ly,RhinoCAMwillgenerateGcodethatwillnotcontainanycolisions.

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Fig. 32

F E E D S & S P E E D S TA B TheexpressionFeeds&Speedsreferstothefeedrate,orrateatwhichthemachinemovesthroughyourmaterial(expressedininches/minute),andthespeedatwhichthespindlespins(expressedinrotations/minute).Therearemanyfactorsthateffectthevaluesyouselectforfeedsandspeeds.Thesefactorsinclude,hardnessofmaterial,stepoverandstepdowndistances,numberofflutesonthecutter,diameterofthecutter,etc.PageX ofthistutorialcontainsaguideforselectingvaluesforfeedrate,spindlespeed,stepoverandstepdown.Inthecaseofthisproject,IamcuttingmyshapeoutoffoamsoIcanbeveryaggressivewiththesevalueswithoutfearofdamagingthecutter.1.Setvaluesforfeedsandspeeds(Fig.32)C L E A R A N C E P L A N E TA B

Fig. 33

ThissettingtellsthemillthatwhenitretractsfromthematerialitmustdosotoacertainZdistance(whichyouwillset)beforetransferingtoanotherareatocut.1.LMB,StockMaxZ+Dist(Fig.33)2.Setvalueto.25”Thissettingwillensurethatthecutterretracts1/4”abovethethicknessofthestockbeforetransferingtoavoidcolisions.

Fig. 34

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C U T PA R A M E T E R S TA B Inthistabyouwillsetthestepoverdistance.Thisvalueisex-pressedasapercentageofthediameterofyourcutter.Inmycase,Iamusinga1/4”endmillandIwantittostepover50%(Fig.34)whichwouldequal1/8”.1.ReferencetheStepover/StepdownguideonpageX foradviceonStepoveramount2.Enterthisvalue(Fig.34)

Z C O N TA I N M E N T TA B ThereisnoCutLevelsTabinParallelFinishingbecause,asyouwillsee,thecuttermovessimultaniouslyintheX,YandZaxis.Theamountofmaterialyouremovewiththefinishingpassissimplywhatevermaterialislefttoachievethetoler-anceyouneed.However,ifyoufindyourselfinasituationinwhichyouneedtorestricttheZmovementitisdonehereintheZContainmentTab,bycheckingInsertMultipleStep-DownZCuts(Fig.35).Otherthanthat,theonlysettingyouwillchangehereistocheckthebox,SpecifyLowestZ(Fig.35).Thiswillensurethatthecutterwillnotgobelowthebottomofyourpart.1.LMB,SpecifyLowestZ(Fig.35)2.LMB,mouseicon(Fig.35)3.LMB,selectapointonthebottomofyourRhinodrawing

E N T RY / E X I T TA BYouwillnotchangeanythinginthistab.ItshouldcontainthesamesettingsasFig.36.1.LMB,Generate(Fig.36)

Fig. 35

Fig. 36

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N AV I G AT I O N T I P S A N D S I M U L AT I O N S WhileintheMachineJobFolder,youcanRightClickonthetoolpath

youjustcreated(Fig.37).ThisgivesyouquickaccesstoseveralfunctionsincludingRegenerate,Post,SimulateandInformation.

RegenerateIfyouchangeanythinginyourdrawingyoumustregeneratethetoolpathinordertoupdateit.Youwillknowwhenyouneedtoregeneratebecauseyouwillseeasmallredexplosioniconoverthefolderwhichcontainsthetoolpathtoberegenerated(Fig.38).WhileintheMachineJobFolder,RMB,yourtoolpath,LMB,Regenerate.

NOTE: The order of the folders inside the Machine Job Folder is impor-tant. If your Work Zero is below one of your toolpaths, the Work Zero will not apply to that toolpath. This can negate any of your attempts at stock part alignment and cause a collision. Information RhinoCAMhastheabilitytotellyouimportantinformationaboutyourtoolpaths.WhileintheMachineJobFolder,RMB,onyourtoolpath,LMB,Information(Fig.37).Next,youwillseeawindowlikeinFig.39.ThisfeatureismostcommonlyusedtofindouttheMachineTimeofthetoolpath.TheMachineTimeisthetotaltimethetoolpathtakestorunfromthetimeyoustartthespindleuntilitturnsoff.Simulation Thefastestwaytorunasimulationofatoolpathis,whileintheMachineJobFolder,RMB,onyourtoolpath,LMB,Simulate.IfyouwanttoadjusttheSimulationsettingsyoucanaccessthemintheSimulationTab(Fig.5).

Fig. 37

Fig. 38

Fig. 39

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P O S T I N G ThetermPosting,meanstogeneratethefilethatcon-tainstheGcode.Eachtoolpaththatyouwanttorunmustbeposted.Theresultingfileisatextfilewithan.ncfileextension.Inordertopostatoolpath,whileintheMachineJobFolder,RMB,onyourtoolpathfolder,LMB,Post(Fig.37).

ThenextwindowshouldlooklikeFig.40.Afterspecify-ingalocationtosaveyourGcodefile,LMBPost.YourGcodefilewillautomaticallyopeninatexteditingpro-gramlikeNotepad(Fig.41).Feelfreetolookthroughthefilebutbesurenottochangeanything.

Fig. 40

Fig. 41

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F E E D S A N D S P E E D S E S T I M AT E S

F O R S O L I D W O O D StepOver-30%ofCutterDiameter StepDown-20%ofCutterDiameter FeedRate-40Inches/Min. SpindleSpeed-3500-4000RPM F O R F O A M StepOver-50%ofCutterDiameter StepDown-50%ofCutterDiameter FeedRate-80Inches/Min. SpindleSpeed-4000-5000RPM