Degree Thesis

HALMSTAD

UNIVERSITY

Bachelor's Programme in Mechanical Engineering, 180credits

Optimization of Granulate 3D Printer

Focus on cooling

Mechanical Engineering, 15 credits

Oskar Geraldsson, Kristoffer Ylander Mikkelsen

ForewordWe would like to thank our supervisors Johan Wretborn and Håkan Pettersson forthe instructions as well as the rich and fresh ideas that have helped us come to theconclusions of the thesis work. We would also like to thank Fredric Ottermo for thehelp with thermal and fluid mechanics calculations.

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AbstractThe authors, Oskar Geraldsson and Kristoffer Ylander Mikkelsen, together with ABSvenska Konstruktörsbyrån, have customized and optimized a granulate 3D printer.The main goal for the authors is to improve the cooling of the liquid ABS plas-tic leaving the nozzle to prevent displacement and dislocation during the printingprocess. Furthermore the printers current state is poor resulting in further workregarding the overall mechanics of the printer such as the power supply, electricalmotors and linear guides.

The authors have studied existing 3D printers and searched through scientific ar-ticles to get inspiration and knowledge of the mechanical process of the printers aswell as the materials.

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Contents1 Introduction 1

1.1 Scope . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11.2 Problems Ranked from Most to Least Important . . . . . . . . . . . 11.3 Demarcation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1

2 Background 22.1 Environment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2

2.1.1 ABS vs. PLA . . . . . . . . . . . . . . . . . . . . . . . . . 32.2 Previous Thesis Work . . . . . . . . . . . . . . . . . . . . . . . . . 3

3 Theoretical Framework 43.1 Fused Deposition Modeling . . . . . . . . . . . . . . . . . . . . . . 43.2 Scientific Method . . . . . . . . . . . . . . . . . . . . . . . . . . . 4

3.2.1 Natural Convection . . . . . . . . . . . . . . . . . . . . . . 43.2.2 Fluid Mechanics . . . . . . . . . . . . . . . . . . . . . . . 5

3.3 Extrusion with Screw . . . . . . . . . . . . . . . . . . . . . . . . . 53.4 Printing with Plastic Granulate . . . . . . . . . . . . . . . . . . . . 5

3.4.1 Dampness of Material . . . . . . . . . . . . . . . . . . . . 63.4.2 Temperature and Cooling . . . . . . . . . . . . . . . . . . . 6

3.5 Software . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 73.6 Brainstorming . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 83.7 Prototyping . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8

4 Method 94.1 Pre-Study . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 94.2 Timeline . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 94.3 Analysis . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9

4.3.1 Cooling System . . . . . . . . . . . . . . . . . . . . . . . . 94.3.2 Heatbed . . . . . . . . . . . . . . . . . . . . . . . . . . . . 104.3.3 Z-Axis . . . . . . . . . . . . . . . . . . . . . . . . . . . . 104.3.4 Wiring . . . . . . . . . . . . . . . . . . . . . . . . . . . . 104.3.5 Software . . . . . . . . . . . . . . . . . . . . . . . . . . . 10

4.4 Brainstorming . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11

5 Results 125.1 Cost Analysis . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 125.2 Heatbed . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12

5.2.1 Leveling . . . . . . . . . . . . . . . . . . . . . . . . . . . 125.2.2 Heating . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13

5.3 Wiring . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 135.4 Extrusion . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 145.5 Cooling . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14

5.5.1 Calculations . . . . . . . . . . . . . . . . . . . . . . . . . 15

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5.6 Software . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16

6 Discussion 176.1 Critical Analysis . . . . . . . . . . . . . . . . . . . . . . . . . . . 18

6.1.1 Social Aspects . . . . . . . . . . . . . . . . . . . . . . . . 186.1.2 Economical Aspects . . . . . . . . . . . . . . . . . . . . . 186.1.3 Environmental Aspects . . . . . . . . . . . . . . . . . . . . 18

7 Conclusion 197.1 Division of Labor . . . . . . . . . . . . . . . . . . . . . . . . . . . 19

8 References 20

9 Appendix 229.1 Level Heatbed (Previous) . . . . . . . . . . . . . . . . . . . . . . . 229.2 Level Heatbed (Wheel Removed) . . . . . . . . . . . . . . . . . . . 239.3 Level Heatbed (Improved) . . . . . . . . . . . . . . . . . . . . . . 249.4 Timetable . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 259.5 Natural Convection Calculations . . . . . . . . . . . . . . . . . . . 269.6 Fluid Mechanics Calculation . . . . . . . . . . . . . . . . . . . . . 27

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1 Introduction

1.1 ScopeThe purpose of this thesis work is to finalize the 3D printer and make sure that theprints have high repeatability every print while the machine remains fully enclosedand aesthetically pleasing. The goal is to publish the machine and compete withother printers in the same category.

The main objective is to refine the cooling of the melted plastic (ABS in partic-ular) to prevent dislocation while printing without supports.

1.2 Problems Ranked from Most to Least Important1. Cooling of the liquid ABS plastic leaving the nozzle

2. Add three phase power

3. Make the printer more reliable

4. Make the printer more aesthetically pleasing

1.3 DemarcationThe main focus of this project is to improve the cooling of the ABS plastic in gran-ulate form. Due to several complications regarding the wiring, the heated bed,motors, linear guides as well as software these will also be included in the report.The conversion from single phase connection to three phase power was not done bythe authors due to disqualifications however is still stated in the report.

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2 Background

AB Svenska Konstruktörsbyrån is a Swedish consultant company located in Halm-stad. For several years they have had students from University of Halmstad developtheir 3D-printer. On January 2017 two mechatronical engineer students replacedand updated the electronics of the machine to increase the reliability.

This year (2019) they searched for student that could finish the project, with thegoal to launch the 3D-printer as a cheaper alternative on the market. The main as-pect that lowers the price is the use of plastic in a form of pellets, granulate, ratherthan wire. The available machines in this scale costs about 5 million SEK [15] asof writing of this rapport.

ABS plastic is not as commonly used in 3D-printing as PLA plastic, the main reasonfor this is the requirement of a heatbed for the ABS plastic to not dislocate, shrinkor warp. However, ABS has better thermal and mechanical properties and creates asturdier final product as well as being a lot cheaper than PLA. This is because theinjection-molding business uses ABS granulate [8] and because plastic in pelletsform is a lot cheaper to make than wire form.

The 3D-printer project is divided into two groups, one group focus on the cool-ing while the other focus on the humidity of the ABS plastic. This report containsthe cooling but both groups are responsible for the outcome.

2.1 Environment

3D-printing is a relative new process that enables a person or company to makeprototypes much faster and cheaper than conventional methods such as injection-molding. This also makes 3D printing less harmful for the environment since thereis no need to make expensive tools. In Sweden the recycling of plastic packagingis common and in 2017, 44% of all plastic packaging was recycled (not includingPET-bottles) [10]. This might seems like a lot, but compared to the global plasticwaste recycled 2015, 19.5%, its more than double [11].

Plastic isn’t known for being good for the environment considering the energy re-quired to get rid of it. But on the other hand, using plastic in a 3D printer is quiteeffective considering old plastic can be reused and recycled. Another factor thatcould play in on the environment is the energy consumption required to heat theextruder as well as the heatbed. More specifically when heating a large 3D printingas shown in this thesis work, it required a great amount of energy however if theavailability to harvest electricity from a more natural source was available it wouldnot be as big of an impact.

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2.1.1 ABS vs. PLA

There are pros and cons for using both ABS and PLA. Companies that print outmechanical parts tend to use ABS for its sturdiness and higher melting point whilePLA is an easier material to print with and use. PLA is mostly used by smallermachines, it don’t require a heatbed and want a more elegant print with smoothersurfaces, also it is biodegradable. ABS is much broader and available in granulateform and that is why ABS was chosen.

2.2 Previous Thesis WorkThe printer has been an ongoing project for over four years, and this thesis is basedon the fourth group working on it. The 3D-printer has gone through different stages,from building the frame to installing motors and making the machine capable of itspurpose. This year there are two groups working simultaneously on the machinehowever on different specific areas. This requires a form of correlation and goodcommunication for the result to be optimal.

A lot of small problems have been fixed to make the machine operational, this meanta much broader involvement making the authors work outside of their comfort zone.

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3 Theoretical Framework

3.1 Fused Deposition ModelingFused Deposition Modeling is a popular manufacturing method for prototypes andis the theory that 3D printing is based on. This method builds on the idea of plas-tic being extruded through a heated nozzle and then in turn is built layer by layer.Stratasys owned the rights to this method making it known as Fused Filament Fab-rication. [14]

3.2 Scientific MethodCalculating the cooling of the plastic is done with natural convection and fluid me-chanics. Every formula is from the book "Fundamentals of Thermal-Fluid Sci-ences" [3].

3.2.1 Natural Convection

The first formula is for heat dissipation; Q is the dissipated heat, h is a constantwhich depends on e.g heat, flow speed, turbulent or laminar flow etc. A is the areaand ∆T is the change in temperature.

Q = hA(Ts −T∞) or Q = hA∆T (1)

This is the formula for the Nusselt number (Nu), which is a ratio of convective toconductive heat transfer.

Nu =hLk

(2)

Rayleigh number (RaL), is a product of Grashof number and Prandtl number. Itdescribes the relationship between; buoyancy, viscosity, momentum diffusivity andthermal diffusivity within a fluid.

RaL =gβ (Ts −T∞)L3

v2 Pr (3)

β can be re-written as seen below.

β =1

Tavg(4)

The average temperature is self-explanatory.

Tavg =Ts +T∞

2(5)

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Differential equation for solving how much time it takes for the melted liquid toreach the point where it hardens.

Q = -mcTs = hA(Ts - T∞) =>Ts + hA

mc Ts = hAT∞

mc =>

Ts(t) + hAmc Ts(t) = hA

mc T∞ =>

Ts(t) = (Ts,0 −T∞)ehAmc +T∞ (6)

Ts,0 is the temperature of the plastic when it leaves the nozzle,T∞ is the surrounding temperature andTs(t) is the time, in seconds, it takes from T2,0 to T∞.

3.2.2 Fluid Mechanics

Isotropic process as well the first law of fluid mechanics.

v =

√2k

k−1RT1(1−

P2

P1)

k−1k (7)

This will be used to calculate the velocity of the air pressure pushed through anozzle with 3mm in diameter. This is mainly to get an idea of how much pressureis being forced onto the ABS plastic to cool it.

3.3 Extrusion with ScrewExtruding plastic through a screw is commonly used in the injection-molding busi-ness as briefly stated in [2.1], basically plastic granulate is dropped in a screw whichfeeds is through heating elements. The heat makes the plastic change from solid pel-lets to liquid form, the further the plastic travels the higher the pressure is due tohow the screw is shaped, see figure 1. The hot pressurized liquid can then be pushedinto molds, this process is common due to its high repeatability and low scrap rates.The downsides are expensive tooling costs and the great lead times when changingproducts, this method was implemented in the 3D-printer [5].

3.4 Printing with Plastic GranulateMost 3D printers use plastic in wire form that is rolled around a quill, it’s createdby carefully and precisely melting plastic in to a fine wire. This type is great fordelivering precision into the print. Granulate form is made in a similar fashionexcept the wire is cut into small flakes. This granulate form does not deliver a finequality however it’s a lot cheaper [1]. The main reason for this is that the wiringmethod requires a quill that’s quite expensive to manufacture.

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Figure 1: Common Extruder [12]

3.4.1 Dampness of Material

The dampness of the material can be a crucial problem in 3D printing, if the materialcontains a lot of water it requires more energy in order for it to melt. Moist plasticcan be noticed by the crackling noise and this causes vaporization to build up in theextruder causing a lot of pressure. Then pressure then causes the print quality to belowered below the acceptable standard.

3.4.2 Temperature and Cooling

3D printing requires great temperature regulation to easily change the physical statefrom solid to liquid form. The plastic changes states in the hotend (therefore thename) and when it leaves the nozzle it begins to cool until it hits the heatbed. Fur-thermore it needs to be cooled correctly in order for the plastic to fuse together withthe previous layers in order for the build to be smooth and even.

Heatbed Not every material that is available for 3D printing requires a heated bed,but often a heated bed gives the material better adhesion. Temperatures between 45 -115°C [4],cover almost every 3D-printable material, for ABS the ideal temperatureis 85°C for maximal adhesion. The heating elements are silicone heaters whichessentially is a wire-loop encased in silicon [9]. When current is pushed throughthe loop the wires heat up, this is a simple heater and with an added temperature-sensor the heater can be controlled precisely.

Hotend As stated in [3.4.2] the hotend is the part of the machine that changes theplastics physical state from solid to liquid. With the help from heating strips thenozzles reaches the target temperature for the specific plastic used however if theplastic rises it can clog the screw. Generally, a fan is attached to prevent this formtaking place, as seen in figure 2.

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Figure 2: Extruder Fan

3.5 Software

The 3D printing software turned out the be a challenge. Several modifications weremade to make the software compatible with the motors. This process starts withthe settings and geometry that are controlled through a 3D slicing software calledSimplify3D. These commands are then uploaded on the Octoprint printing serverinstalled on a Linux platform which then sends commands to the control boardwhich works as the brain of the printer.

G-code is the universal language for 3D printing and the mechanical properties arebased on the G-code typed in the terminal of Octoprint. G-code is mainly used incomputer-aided manufacturing to control automated machines, like CNC machinesor 3d printers.

Simplify3D is a 3D slicing software where STL files are uploaded and the gen-eral tuning settings for the print quality, primary layer heights and G-code scriptscan be applied. The software also gives the user a general idea of how each layerwill be built as well as the positioning and scale in the Cartesian coordinate system.

Octoprint is an open source 3D print controller application. Octoprint providesa web interface for controlling the 3D printer through G-code sent to the controlboard. Through Octoprint the user can monitor the print job as well as the printeritself primarily the temperature of the hotend (nozzle) and the heatbed (printingsurface). Octoprint uses a plugin system and these plugins can be installed fromGithub and allows various visualization assistants.

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3.6 BrainstormingBrainstorming is a problem solving technique where the members of the groupwrites down their ideas on pieces of paper and continues until they have no newideas. It is important that during the brainstorming process no ideas are seen as bad,the goal is to have as many different solutions as possible. Afterwards the ideas areevaluated and the best ideas are further developed.

3.7 PrototypingThe prototyping process is to materialize the solutions and try it out, when dealingwith a physical prototype problems that was overlooked at the idea-stage is discov-ered and can be fixed. When prototyping functions is valued more than appearance.

The university’s metal workshop was at the authors disposal and they received helpfrom Håkan Pettersson, the man responsible for the workshop.

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4 MethodThe initial objective was to improve the cooling of the ABS plastic during the print.Primarily the authors did a pre-study to determine the accomplishments of the ear-lier thesis works. This information was studied through the thesis reports that werewritten about this specific 3D printer.

4.1 Pre-StudyDuring the pre-study the authors familiarized themselves with the previous thesis,general mechanical functions, thermodynamics, as well as a study of materials.From this the authors were able the take decisions regarding the improvement ofthe printer.

4.2 TimelineA timeline was made to keep the authors on track throughout the project, milestoneswere placed to keep track of the important stages, see appendix 11.4.

4.3 AnalysisThe consistency of the prints was not satisfactory, to determine what the problemswere an analysis was conducted covering all areas of the printer.

4.3.1 Cooling System

The existing cooling system was just for visual representation since it did not work,the two centrifugal fans did not cool the melted plastic. During tests there was novisible difference with the fans on or off.

A new air cooling system had to be made, air pressure was an alternative sincethere was an air compressor in the workshop as well as pneumatic tubes and valves.The ability to use pressurized air with a custom nozzle and easily regulate the pres-sure will come in handy to find out the optimal pressure required to get a smoothprint with good contours.

To get the volume per minute of air released from the nozzle a calculation wasmade. This calculation is important to find the optimal air pressure estimated to bebetween 1 and 2 bars (+1 bar from atmospheric pressure). To cool air over a largersurface area with regulated compressed air is the optimal solution.

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4.3.2 Heatbed

Heating Due to the lack of power required to heat the bed rapidly a three phaseconnection was added to replaced the previous single phase connection. This wouldmake the work more effective and not waste too much time heating up the heatbedrather than printing.

Leveling The z-axis probe attached to the motor was also used to gather data inorder to level the bed. Being supported on rails attached to the general structure.

4.3.3 Z-Axis

The z-axis carrying the extruder is not in equilibrium, the side with the motor isheavier than the other which causes the z-axis to tilt. This has not been permanentlycorrected, before each print the z-axis is manually leveled. Shown in the the figurebelow, a spirit level is placed on the z-axis to represent the change in horizontalheight.

Figure 3: Crooked z-axis

4.3.4 Wiring

The power going in to the machine consisted of one 230V 16A line and one 230V10A line, it was upgraded by an outside contractor to three phase power (three lineswith 230V 16A). This will be tested by recording the increase in temperature of theheatbed every 5 minutes.

4.3.5 Software

The software was outdated and not functioning correctly so an update was required,mainly due to the lack of plugins for the older Octoprint version. These plugins

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serve to ease the visualization aid and general ease of use. This is done by research-ing on forums and guides due to lack of knowledge.

4.4 BrainstormingThe authors brainstormed together and came up with many different ideas and andsolutions for their problems. The best ideas were further developed and discussedwith SVKB for approval. After approval the idea was written down, optimized andtested.

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5 Results

5.1 Cost Analysis

The budget had no limit, the authors just had to confirm the orders with SVKB,almost every item was a consumable.

Name Quantity (pc) Price (SEK)Wire 1 17.9Vinyl hose 10m x 9mm 1 54.9Marking labels 1 32.9Hose clamp 11 - 13mm 4 22.9Braided cable sock 12mm 1 74.9Cable ties 1 54.9Storage box 2 159.8Storage box lid 2 59.8Hose clamp 50 - 70mm 2 22.9PVC pipe 30° 50mm 1 19.9PVC pipe 45° 32mm 1 54.9Totalt 575.7

Figure 4: Cost Analysis

5.2 Heatbed

5.2.1 Leveling

With the ABL-script (Automatic Bed Leveling-script) the authors received infor-mation of how even or uneven the bed is. As you can see the heatbed is much moreeven now than it was in the beginning. Related pictures of data and height mapscan be found in the appendix section; Previous[9.1], Wheel Removed[9.2] and Im-proved[9.3].

State Min Max DeviationPrevious -0.6 6.5 7.1

Wheel Removed -0.8 2.6 3.4Improved -2.9 0.2 3.1

Figure 5: Heatbed Deviation

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The deviations is less than half now and as seen in the pictures the high- and low-points are in the same locations almost every time. With even more tinkering theauthors are confident that the deviation can be brought down to less than 1.5 - 2mm.

5.2.2 Heating

With the change from single phase to three phase the siliconheaters are warming upmuch faster. The results are displayed below in figure 5.

Figure 6: Temperature over Time

The optimal temperature is 85°C according to our testing and as you can see itonly takes 30 min now instead of never even reaching that temperature before. Theheating elements are limited to 9amps each now instead of 3.25amps.

5.3 WiringThe wiring was done by an external contractor and the results was amazing, fromsingle phase to three phase which meant that the heatbeds could heat up the surfacemuch faster. This also meant that there is only one three phase contact needed in-stead of two single phase contact.

Before:230V * 16A = 3680W230V * 10A = 2300WTotal 5980W = 5.98kW

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Now:3 * 230V * 16A = 11040W = 11.04kW.11.04 / 5.98 = 1.846153846 = 1.846 = 84.6% increase.

5.4 ExtrusionDue to the lack of time and miss communication between the two groups, dry gran-ulate have not yet been tested properly leaving no results regards to the extrusion.A test to dry the granulate in a standard kitchen oven was done and the results areshown in the figure 7 below, humid material on the left and dry material on the right.

Figure 7: The difference in dry granulate and moist.

5.5 CoolingThe cooling design improves the print quality as seen in Figure 8. Air pressure of2 Bar was the sweet-spot according to all of the tests. The new cooling system isshown in Figure 9 below.

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Figure 8: Image of the new cooling system from below.

Figure 9: Cooling with Different Pressures.

5.5.1 Calculations

With formula (6) it takes 15 minutes and 23.5 seconds for 31.5 grams of ABS tocool down from 230°C to 110°C, that is roughly two layers of ABS with the dimen-sions 100 x 100 x 3 mm.

Using formula (7) we were able to get the speed to 198.402 m/s. This howeverwas without taking some external factors into consideration such as the distance tothe compressor. However, with this result we can get an understanding of how muchforce is being pressurized on the plastic as we print.

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Calculation files can be found in appendix 9.5 and 9.6, calculations was done inMathematica 12.0.

5.6 SoftwareThe 3D-printer is working better and faster now after updating the software andeasier to use since there has been added functions and button so the end-user doesn’tneed to write gcode. Rather than the 3D printer measures 9 points with the z probeto bed level before every print, a test file was written to specifically measure the bedleveling. This gave an easier and quicker way to start a new print.

Figure 10: Gcode Script

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6 DiscussionAt the start of the project we quickly realized that this project would turn out to bea lot more complex than initially planned. Due to this our timetable wasn’t accurateand a lot of other areas turned out to be set backs. Even though other areas weresetbacks we decided that this was a crucial part of the 3D printer and required alot of time and effort in order to work properly. A prime example of this was theamount of time and effort we put into learning and using the software as well as theheatbed leveling.

As mentioned earlier in the report the software was crucial for us to understandin order to command the printer and understand how each setting can effect theprint. A further improvement regarding the software would be if we understood andresearched more about the slicing software (Simplify3D) more since a lot of G-codecommands and be used to ease the process and make the prints smoother and moreaccurate.

Due to lack of time we decided not to replace parts from previous years since thatwould most likely create a lot more problems regarding the mechanical movementand operation of the printer. Instead we decided to modify the feeding of the ABSplastic as well as removing the cogwheel for the belt pulley.

Considering the cooling, we were quite pleased with the results. After realizingwe had air-pressure available in the workshop, we were able to connect the com-pressed air with our nozzle which gave great cooling over a larger area. It was agreat improvement replacing the old plastic nozzle with a new steel nozzle withgreater spread of the compressed air covering a substantially larger area.

The level of the heatbed is very important for good quality prints, due to how theheatbed was built it was hard to level it properly. If there was time we would like tohave the heatbed rebuilt so it was not connected to the main structure anymore, thiswould have made it a lot easier to level.

The calculations for the natural convection is not entirely correct since it takesabout five minutes to print. This means the print is cooling down alongside it be-ing printed, the calculations is done with the print done and all of it homogeneous230°C. The problem is that it’s a lot harder to calculate different cooldown zones,but the calculations still gives us a rough estimate.

Due to several factors that can affect the calculations for the airspeed through thenozzle. The air compressor is located in a different room next to the workshop.The distance the air travels might affect the pressure flowing into the printer. Sincetemperature effects the outcome of the velocity of air, we assumed the temperaturein the room was around 22 degrees Celsius but this might vary.

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6.1 Critical Analysis6.1.1 Social Aspects

Considering the social aspects of the 3D printer regards to health would involve thefumes released from the melted plastic and it’s effects on the user. On the other handproducts and prototypes could be manufactured locally, with better knowledge andtools to handle the fumes it would benefit the community.

6.1.2 Economical Aspects

Since the SVKB’s goal was to create a cheaper alternative of a big scale 3D printerto compete against other existing ones on the market the budget was not quite de-fined, however building the parts from reusable materials from the workshop wasviable. We were able to construct a new cooling system with just about 580 SEKwhich we consider was the cheapest alternative with the best results. The cost anal-yses is shown in Figure 4 for a more detailed visualization.

6.1.3 Environmental Aspects

As stated in section 2.1, 3D printing a relative new process and is a more environ-mentally friendly alternative to creating a few prototypes rather than mass produc-tion as in plastic moulding.

We quickly realized that the amount of plastic used for printing at such a largescale required quite a lot of ABS plastic granulate. However due the fact that ABSplastic granulate is often recycled from various plastic sources this wouldn’t impactthe environment greatly. The plastic granulate however was often imported fromeastern Asian countries such as China and the transport is considered a benefactorto the global warming from the gases released from airplanes or other modes ofshipping. We were however not able to find any alternative plastic manufacturersaround Sweden.

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7 ConclusionThe project have been an adventure through the world of 3D-printing and 3D-printers, the authors have explored areas of these subjects they didn’t even realizedplayed a part in the outcome of the prints. Due to some lack of communication andknowledge in the area the authors have not completed as much as they would liketo do. Yet they have learned a lot about the subject and are happy they chose thisproject.

The problems stated in the scope section of the thesis report have mostly beensolved. With the methods used the authors were able to get appropriate resultsin both the calculation part as well as the physical build. The print quality has beenimproved a lot but could be improved more, but that would require rebuilding someparts of the machine.

7.1 Division of LaborWe the authors think the division of labor have been fair and that everyone in thegroup have done their part. It has been a naturally divide because of our personalinterests, one is a little more interested in programming while the other is more ex-perienced in the workshop. Even though both of the authors have been responsiblefor different parts they have never felt like one is doing more than the other.

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8 References

[1] Berggren, Kenneth. Konstruera i Plast. Industrilitteratur, 2008.

[2] Landry, Taylor. “Beat Moisture Before It Kills Your 3D Printing Filament.”MatterHackers, 28 July 2016, www.matterhackers.com/news/filament-an-water

[3] Cengel Yunus A., et al. Fundamentals of Thermal-Fluid Sciences. McGraw-HillHigher Education, 2012.

[4] “3D Printing Material Properties Table - Compare Top Filaments.” Simplify3DSoftware, 2019, www.simplify3d.com/support/materials-guide/properties-table

[5] Rogers, Tony. “Everything You Need To Know About Injection Mold-ing.” Everything You Need To Know About Injection Molding, 2019,www.creativemechanisms.com/blog/everything-you-need-to-know-about-injection-molding

[6] “Wire Size & amp; Current Rating .” Current Rating,www.jst.fr/doc/jst/pdf/current_rating.pdf

[7] Björklund, S., Gustafsson, G., Hågeryd, L. Rundqvist, B. (red.) (2015).Karlebo handbok. (16., omarb. och utvidgade uppl.) Stockholm: Liber.

[8] Leijon, W. (red.) (2014). Karlebo Materiallära. (15. uppl.) Stockholm:Liber.

[9] "Flexible silicone rubber Fiberglass insulated heaters", Omega,https://assets.omega.com/pdf/process-heaters-and-coolers/flexible-heaters/SRFR_SRFG.pdf

[10] "Återvinning av förpackningar i Sverige", SCB, https://www.scb.se/hitta-statistik/sverige-i-siffror/miljo/atervinning-av-forpackningar-i-sverige/

[11] "Global plastic waste by disposal", Our world in data,https://ourworldindata.org/faq-on-plasticshow-much-of-global-plastic-is-recycled

[12] Stromvall Hans-Erik. Producera i Plast. Sveriges Verkstadsindustrier(VI), 2002.

[13] Klason, Carl, et al. Plaster: Materialval Och Materialdata. SverigesVerkstadsindustrier, 2001.

20

[14] Comprehensive materials processing : 13 volume set /editor-in-chief, M. S. J. Hashmi. [Elektronisk resurs]. Elsevier.https://www.sciencedirect.com/science/article/pii/B9780080965321010025

[15] Gigantic The Box 3D printer revealed with 2.5 m3 build volume, 1200 mm/sec3D print speeds, 3ders.com, http://www.3ders.org/articles/20160718-gigantic-the-box-3d-printer-revealed-with-2-5-m3-build-volume-3d-print-speeds.html

21

9 Appendix

9.1 Level Heatbed (Previous)

22

9.2 Level Heatbed (Wheel Removed)

23

9.3 Level Heatbed (Improved)

24

9.4 Timetable

Optimering av 3D-skrivare med avseende på kylningOskar Geraldsson & Kristoffer Ylander Mikkelsen

Project Start Date Display Week 1

Project Lead21 22 23 24 25 26 27 28 29 30 31 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26

WBS TASK LEAD START END DAYS%

DONEWORKDAYS

M T W T F S S M T W T F S S M T W T F S S M T W T F S S M T W T F S S M T

1 Viktiga datum mån 1-21-19 mån 1-21-19 1

1.1 Projektstart [Name] mån 1-21-19 mån 1-21-19 1 0% 1

1.2 Projektbeskrivning mån 1-21-19 fre 2-01-19 12 0% 10

1.2.1 Inlämning mån 1-28-19 fre 2-01-19 5 0% 5

1.3 Rapport fre 2-01-19 fre 6-21-19 141 0% 101

1.3.1 Preliminär inlämning fre 5-10-19 fre 5-10-19 1 0% 1

1.3.2 Halvtidsrapport fre 3-15-19 fre 3-15-19 1 0% 1

1.3.3 Slutgiltig inlämning fre 5-31-19 fre 5-31-19 1 0% 1

1.3.4 Redovisning ochOpponering

tis 5-21-19 tis 5-21-19 1 0% 1

1.3.4 Inlämning DIVA fre 5-31-19 fre 6-21-19 22 0% 16

1.4 UTEXPO ons 6-05-19 tor 6-06-19 2 0% 2

2 Kylning fre 2-01-19 fre 5-31-19 120 86

2.1 Undersökning fre 2-01-19 sön 3-03-19 31 0% 21

2.2 Utveckling sön 3-03-19 tis 4-02-19 31 0% 22

2.3 Utvärdering tis 4-02-19 tor 5-02-19 31 0% 23

2.4 Färdigställning tor 5-02-19 fre 5-31-19 30 0% 222.5 [Task] - ##### 0% -3 Kylning - - ##### ########3.1 Undersökning - - ##### 0% ########3.2 Utveckling - - ##### 0% ########3.3 Utvärdering - - ##### 0% ########3.4 Färdigställning - - ##### 0% ########3.5 [Task] - - ##### 0% ########4 Design - - ##### ########4.1 Undersökning - - ##### 0% ########4.2 Utveckling - - ##### 0% ########4.3 Utvärdering - - ##### 0% ########4.4 Färdigställning - - ##### 0% ########4.5 [Task] - - ##### 0% ########

Gantt Chart Template © 2006-2018 by Vertex42.com.

Week 2Week 11-21-2019 (måndag)

28 jan 201921 jan 2019

Week 34 feb 2019

Week 411 feb 2019 18 feb 2019 2

Week 5

23 24 25 26 27 28 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17

S S M T W T F S S M T W T F S S M T W T F S S

Week 811 mar 20199

Week 625 feb 2019

Week 74 mar 2019

krivare med avseende på kylningfer Ylander Mikkelsen

Display Week 9

18 19 20 21 22 23 24 25 26 27 28 29 30 31 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 1 2 3 4 5

LEAD START END DAYS%

DONEWORKDAYS

M T W T F S S M T W T F S S M T W T F S S M T W T F S S M T W T F S S M T W T F S S M T W T F S S

mån 1-21-19 mån 1-21-19 1

[Name] mån 1-21-19 mån 1-21-19 1 0% 1

mån 1-21-19 fre 2-01-19 12 0% 10

mån 1-28-19 fre 2-01-19 5 0% 5

fre 2-01-19 fre 6-21-19 141 0% 101

fre 5-10-19 fre 5-10-19 1 0% 1

fre 3-15-19 fre 3-15-19 1 0% 1

fre 5-31-19 fre 5-31-19 1 0% 1

tis 5-21-19 tis 5-21-19 1 0% 1

fre 5-31-19 fre 6-21-19 22 0% 16

ons 6-05-19 tor 6-06-19 2 0% 2

fre 2-01-19 fre 5-31-19 120 86

fre 2-01-19 sön 3-03-19 31 0% 21

sön 3-03-19 tis 4-02-19 31 0% 22

tis 4-02-19 tor 5-02-19 31 0% 23

tor 5-02-19 fre 5-31-19 30 0% 22- ##### 0% -- - ##### ########- - ##### 0% ########- - ##### 0% ########- - ##### 0% ########- - ##### 0% ########- - ##### 0% ########- - ##### ########- - ##### 0% ########- - ##### 0% ########- - ##### 0% ########- - ##### 0% ########- - ##### 0% ########

Gantt Chart Template © 2006-2018 by Vertex42.com.

Week 10Week 91-21-2019 (måndag)

25 mar 201918 mar 2019

Week 111 apr 2019

Week 128 apr 2019 15 apr 2019

Week 1422 apr 2019

Week 13 Week 1529 apr 2019

4 5 6 7 8 9 10 11 12

S S M T W T F S S

Week 166 maj 2019

59

kylning

Week 17

13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 1 2 3 4 5 6 7

DAYS%

DONEWORKDAYS

M T W T F S S M T W T F S S M T W T F S S M T W T F S S M T W T F S S M T W T F S S M T W T F S S M T W T F S S

1

1 0% 1

12 0% 10

5 0% 5

141 0% 101

1 0% 1

1 0% 1

1 0% 1

1 0% 1

22 0% 16

2 0% 2

120 86

31 0% 21

31 0% 22

31 0% 23

30 0% 22##### 0% -##### ############# 0% ############# 0% ############# 0% ############# 0% ############# 0% ############# ############# 0% ############# 0% ############# 0% ############# 0% ############# 0% ########

Gantt Chart Template © 2006-2018 by Vertex42.com.

Week 18Week 1720 maj 201913 maj 2019

Week 1927 maj 2019

Week 203 jun 2019

Week 241 jul 201910 jun 2019

Week 2217 jun 2019

Week 21 Week 2324 jun 2019

25

9.5 Natural Convection Calculations

26

9.6 Fluid Mechanics Calculation

27

PO Box 823, SE-301 18 HalmstadPhone: +35 46 16 71 00E-mail: registrator@hh.sewww.hh.se

Oskar Geraldsson

Kristoffer Ylander Mikkelsen