Report on additive manufacturing for class credit.

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MET 328 Class Credit Additive Manufacturing Project
Joe Legan

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Executive Summary
This project is being performed in an effort to use life experience and experience gained from an
internship as a substitute for the MET 328 class.
The purpose of this report is to document the processes and technologies that can be used in
modern additive manufacturing.
This project used a 3D Systems Capture scanner that uses white/blue light to digitize an artifact.
This was followed by the use of Geomagic Design X to manipulate the scan data and to model
the solid. The last software used was Cura. It was used to create the G-Code for an Axiom
Airwolf Dual Head 3D printer.
As with most 3D printed material, the finished product is a likeness of the actual artifact. The
surface finish cannot always be duplicated due to the nature of the process. This surface finish
discrepancy can lead to some errors in the printed part.
It has been discovered that there is a problem with the 3D printed part. There is a small hole from
between the central hole and one of the side angled holes. It is unclear if this error is caused by a
defect in the model or if this was caused during the actual printing process.
Even with the mentioned error the overall quality of the print is high considering that the Axiom
Airwolf printer is an entry level unit. The print could easily be put into use as a mock up
prototype.
This project is an example of some of the technologies and their respective processes that are
available to the manufacturing industry. The scanning and modeling processes are not exclusive
to additive manufacturing and are often used in subtractive as well. I believe that this project has
been a success in thoroughly demonstrating the technologies and processes used.

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Introduction
This project is being performed in an effort to use life experience and experience gained from an
internship as a substitute for the MET 328 class.
The purpose of this report is to document the processes and technologies that can be used in
modern additive manufacturing. More specifically the processes of reverse engineering a given
artifact, modeling a solid and using a 3D printer to recreate the artifact. This project used a 3D
Systems Capture scanner that uses white/blue light to digitize an artifact. This was followed by
the use of Geomagic Design X to manipulate the scan data and to model the solid. The last
software used was Cura. It was used to create the G-Code for an Axiom Airwolf Dual Head 3D
printer.
Each of these steps is covered in more detail in the following section.
Procedures
The procedures have been segmented into 6 functions. These are:
1. Scanning the artifact
2. Mesh manipulation
3. Modeling a solid from the mesh
4. 3D print preparation
5. Slicing the artifact and G-Code creation
6. Operation of the 3D printer
The first step to all of this is setting up the scanner. The scanner chosen for use with this artifact,
a remote oil filter base, is the 3D Systems Capture scanner. The Capture scanner is a desktop
scanner that is intended for use with items no larger than a softball or large grapefruit. It uses
white and blue light displayed in a series of patterns along with 2 cameras to digitize portions of
the artifact. After each image is captured a synced turn table rotates the artifact to next position
and the process is repeated.
The actual steps used for this project are listed below.

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1. OpenGeomagicDesignXand setupthe scannerandturntable.
2. Setupthe registrationtargetforcalibration
3. Clickon AutoExposure and,once complete,selectRegister.
4. Adjustthe locationof the turn table andthe angle of the scannerinorderto obtaina successful
registration.Thisensuresthe accuracyof the data recordedbythe scanner.

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5. Replace registrationtargetwithartifacttobe scannedandselectAutoExposure again.
6. Selectnumberof scansrequiredtofullyscanthe artifact.Rule of thumb:The more complex the
artifactthe more scans will be needed.
7. Clickthe scan button.

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8. Once the scans are completed,clickthe checkmarkonthe scannerdialogbox.
9. SelectYesto runthe MeshBuildupWizardandproceedthroughthe 5 steps.
10. Save the newlymergedscanstoyour selectedlocation.
11. Repeatthisprocessuntil all desiredfeaturesonthe artifactare fullyscanned.

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The nextstepor processis manipulatingthe meshesof the individual scans.Thismustbe done inorder
to combine the datafrom multipleartifactpositionsintoasingle cohesive mesh.There maybe asfewas
2 artifactpositionsandupto as manyas neededforthe scannertofullydigitize the artifact.Forthis
artifacta total of 3 scans were required.Againthe actual stepsusedare listedbelow.
1. Importeach scan so thattheycan be alignedtogethertobuildacomplete mesh.
2. Select2 of the total scans andselectunderthe Alignmenttabthe AlignBetweenScanData.
3. For thissetof scans I have usedthe Local BasedOn PickedPointmethod.

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4. The resultcan be seen.Repeatthisprocessuntilall scansare consolidated.
5. Selectthe PolygonsTabandselectCombine tocreate asingle entityoutof the multiple scans.
6. Decimate the datadownfor quickerprocessingtime.Thisdoesn'taffectthe qualityof the mesh.
Usually,the ideal numberof polygonsisaround1millionpolygons.Thisprojectwasupwardsof
4.3 millionbefore decimation.

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7. Once combined anddecimated the meshneedstobe segmentedintoregionsforsimpler
modeling.Selectthe AutoSegmentfeaturefromthe RegionTab.Setthe Sensitivitylow for
speedandsimple featuresandhigherformore complex features.
8. Resultof the Regionsegmentation.Eachcolorrepresentsadistinctshape orfeature suchasa
revolution,sphere,plane orcylinder.

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Featuresthatare knownfrominspectionof the artifacttobe congruentcan be mergedas
illustratedbythe Cylinderregionsbeforeandafter.Mergingregionsallow dumbsolidstobe
extractedwithease fromthe regions.
Cylinderregionstobe merged.

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Cylinderregionmerged

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9. Selectthe Alignmenttabanduse the alignmentmethodof choice.ForthisprojectIusedthe
AlignWizardwhichusedthe intersectionof the central hole axisvectorandthe bottomsurface
as the originand assignthe reference planesaspicturedbelow.By aligningthe scanto origin
and reference planes,orthogonal viewscanbe usedanddefined.
The nextprocessisthe modelingof asolidforuse inlaterprocedures.Forthisprojecta sketchwas
createdusinga plane onthe meshitself asthe reference geometry.Infact,forall featuresof this
artifact,each sketchwascreateddirectlyontothe mesh.Fromthese sketches,solidfeatureswere
created.These featuresinclude extrudedbosses,extrudedcuts, sweptcutsandfinallysome fillets.The
modelingfollowsthe same setof rulesasprograms suchas SolidWorks.Meaningthateachsketchmust
be a closedcontourandcannot be self-intersectinginorderfora solidor surface operationtobe
performeduponit.Lastly,care mustbe takenwhenusingthe meshasthe basisfor a sketch.Each edge
may projectmultiplecontourlinesfromthe overlappingof scandata or fromthe camera catchinga
reflection.Whenthere are multiple contourlinesitispossible tocreate sketchgeometrythatis
differentfrom the actual artifact.Thisnecessitatessome classical metrologywithradiusgauges,hole
gauges, micrometersandVerniercalipersinorder toensure thatdimensionsare accurate. Listedbelow
isa quicksummaryof the stepstakentocreate the solidmodel.

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1. ModelingbeginswithaMeshSketchderivedfromthe regionsof the mesh.The resultisa
polyline onthe base plane asevidentby the pinkline.
2. Start tracing the polylinewithsolidlinesinordertostart the solidmodeling.

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3. Solidextrude based uponthe sketch.
4. Repeatthisprocessforeach feature,addingreferenceplanesif needed.

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5. Final Model

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Before the oil filterbase canbe 3D printed,the solidmodel needstobe convertedbackintoa mesh.STL
file.Todo thisthe ConvertTo Meshtool was used.The stepsare listedbelow.
1. Selectthe SolidBodiesinthe view control panel inthe lowerleftof the screen.Thisensuresthat
onlythe newlymodeledfeaturesare convertedbackintoageneric.STLfile.

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2. Selectthe Polygonstabatthe topof the screenand selectthe ConvertToMeshfeature.Select
the solidbodyandclickthe checkmark. A new itemwill appearatthe bottomof the tree that is
the newmesh.Exportthisas a .STL file inorderto use it withthe 3D printersoftware.
The nextoperationusesthe Curasoftware toslice the .STL file andcreate the G-Code forthe printer.
Withthe AxiomAirwolf Dual Headprinterthere are specificinitiationfilesforeachtype of material that
can be used. ForthisprojectABSplasticwas chosendue tothe low costand the fact that the printedoil
filterbase will neveractuallybe putintoservice. The actual stepsinvolvedinthisprocessare listed
below.

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1. Launch the Cura software.The checkered boardisthe buildplate thatisprinteduponandthe
vertical wallsrepresentthe volume thatisprintable space.
2. Load the .STL file thatwas exportedfromGeomagicDesignX.

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3. Rotate and move the model intothe desiredorientationandposition.Keepinmindthat all
overhangswill needsupport somaterial canbe savedor wasteddependinguponthe
orientationselected.Forthismodel itwasrotatedtominimize the amountof supportrequired.
Thissaveson material costand time requiredforthe print.

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4. Because the sweptcutwas facingdowntowardsthe buildplate itwasrequiredtoadd support
for the entire cut.The orientationminimizesthe amountof featuresthatrequire support.The
supportoptionscanbe toggled asshown.
5. The last software processrequiredistodouble checkthe actual G-Code.Throughuse we have
foundthat the Airwolf printerissensitive torequiringanauto-levelingsequence priortothe
actual printing.Thissequence wasthoughttobe includedinthe firmware of the printer,several
incorrectprintslaterwe discovereditwasnot.Thissequence isrequiredtobe includedin the
beginningof the G-Code andiscontainedinthe initiation file thatis loadedbeforeimportingthe
STL file.

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6. The last step is to load the actual file into the printer. The Airwolf printer used can either
use files from a MicroSD or wirelessly if it is networked.
Results/Analysis
The result of this project is the actual 3D printed oil filter base that has been submitted along
with this report, the merged scan data as a STL file and lastly the STP and IGES file of the
modeled solid body.
Conclusions
This project has been an example of some of the modern technologies that can be used for
additive manufacturing. Additive manufacturing shares many processes with subtractive such as
reverse engineering and CAD modeling. One major difference between additive and subtractive
manufacturing is the number of required axis for some complex geometry. One example of this
is this oil filter base. The angled faces and threaded holes that are perpendicular to them require
either a 5 axis mill or multiple fixtures for use with a 2.5 axis mill when machined. Whereas a
3D printer can create this with only 3 axis. This ability could help create a push for 3D printers
with the capability to print metal to become more popular and therefore more affordable. This
could also take the 3D printer out of the prototype room and into the manufacturing area.