Vacuum Formed Masks Materials Lab Workshop
Vacuum Formed Masks: Fall 2018
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Objective The vacuum form mask workshop is a re-occurring event at the Materials Lab in which plastic sheets are heated and pressed over a CNC mold of a faculty members likeness. This process can be broken into four major components: 3D scanning, model post-processing, pre-fabrication and fabrication. The overall object for the workshop is to further explore and develop digital and manual fabrication processes using under-utilized pieces of equipment within the School of Architecture.
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Vacuum Formed Masks: Fall 2018
Researcher Instructor Semester
Aaron McMurry Jennifer Wong Fall 2018
Contents 2
Introduction
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3D Scanning
7 Model Post-Processing - GeoMagic Work Flow - Rhino Work Flow 15
Pre-fabrication
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Fabrication
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3D Scanning Tools
Software
(2) variant temperature photography lights. Konica Minolta Vivid 910
GeoMagic
Description UTSOA has a Konica Minolta Vivid 910 3D non-contact digitizing system. This scanner is located in the digital fabrication section of the Technology Lab in Sutton Hall 1.102. It is free for use by all student in the School of Architecture. The Vivid 910 system is capable of scanning over 300,000 data points with very high accuracy in under one minute. The unit is also equipped with an automated rotary stage for 360 degree captures and will overlay captured geometry with textures captured from the camera lens of the unit.
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Considerations for an Effective Scan In order to achieve a scan as free of holes and voids as possible, the surface scanning (in this case an individuals face) should be as free from oil as possible. The scanner achieves best results when higher Kelvin light is used on a matte surface. Glossy surfaces result in reflected light and hence can cause voids in the resultant scan. While it is not necessary for individuals to close their eyes during the scan, individuals may choose to do so. Eyes can sometimes cause holes in the resultant scan as they are naturally very glossy and reflective surfaces. For additional information regarding the 3D scanner please see the wiki page at: https://wikis.utexas.edu/display/SOAdigitech/3D+Scanning+Guide
a b c d e f g h back elevation
side elevation
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Work Flow
Scanning object
1. Ensure the memory card is inserted into slot (g). 2. Power-on Konica Minolta 3D scanner using power switch (b). 3. Press any key on display (a.) to continue. 4. Select (f) scan.
Light A
Light B Konica Minolta
5. Mirror two lights approximately 3 feet from scanning object and behind the scanner. 6. Set lights to high Intensity and high CRI value. 7. Mirror two lights approximately 3 feet from scanning object. 8. Adjust light barn doors to minimize glare as much as possible. 9. Orient Konica Monica using levers to bring desired region of scanning object into the display (a). 10. Once the desired region has been established press release (c). The resulting image should be as free of darker blue portions as possible.
Levers
11. Once the desired image has been released, press record (d). 12 . Once image has been released safely eject memory stick using button (h) adjacent to memory card slot (g).
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Vacuum Formed Masks: Fall 2018
Scanning object
Model Post-processing Geo-Magic Work Flow: Geomagic transfers the point file created from the Konica Minolta into a 3D file for user manipulation. The desired end result is a watertight mesh ready for manipulation in Rhino.
1. Menu > Insert > Import.
2. Select file from memory card and select “Run Mesh Buildup Wizard”.
3. Highlight unwanted portions. Vacuum Formed Masks: Fall 2018
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3. After deleting selected entities select options desired for mesh. Reduce Noise & Remesh And Fill All Holes To Create Watertight Mesh, must be selected.
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Vacuum Formed Masks: Fall 2018
4. Select desired frame and click export from command bar.
5. Export as .stl to desired location and return memory stick.
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Model Post-Processing Rhino Work Flow: Geomagic will export a watertight mesh via an .stl file. This mesh will need to be manipulated in Rhino prior to being sent to Partworks and then Shopbot for CNCing. A ¼” double fluted wood straight bit can cut up to 1” in depth of materials. Therefore the mesh must be cut transversely into < 1” segments. The following steps display a typical workflow for preparing a mesh to be CNC-ready. Other ways are certainly possible. 1. Import .stl file generated from Geomagic. 2. Run a check command to verify mesh is good.
3. Establish “wanted” regions of mesh by drawing a curve around the desired profile of the object. 4. project curve onto the surface of the object.
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Vacuum Formed Masks: Fall 2018
5. splitmeshwithcurve to remove unwanted mesh from the whole.
6. Verify overall height of the object to determine the amount of mesh needed to be trimmed transversely. 7. Run smooth command until desired results are achieved. 8. Create a plane to establish lower extents and trimming plan of mesh. 9. extrude projected profile curve downwards below the previously created clipping plane. It is important to make sure extruded angle is at or greater than 90 deg. This ensures easy removal of the plastic mask from the mold. 10. Convert extruded polysurface to mesh with mesh command. 11. offset transverse lines in less than 1” intervals to establish transverse cuts. (e.g. ¾” offsets).
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12. Project offset lines onto both the extruded mesh and original model mesh
13. Join perimeter curves to form one closed polyline
14. Splitmeshwithcurve both the extruded mesh and model mesh separately. (A separate command will need to be used. Attempting to split both the extruded mesh and the model mesh together will result in an incomplete mesh).
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Vacuum Formed Masks: Fall 2018
15. Repeat splitmeshwithcurve command for each respective layer until all layers have been divided into ¾” sections. 16. Copy 3D model in accordance with the number of layers (e.g. 3). 17. Delete portions of each model to create separate layers.
18. Using meshfromclosedpolyline close top and bottoms of each layer to create separate layers
19. Join meshes for each layer together to form separate pieces.
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20. Move each combined piece to ground level. This is critical when moving model into CNC software, each piece MUST be on ground level.
21. Check each joined mesh to ensure mesh is good. - If manifold edges exist, used extractnonmanifoldedges command. - If degenerate faces exist use culldegeneratefaces command. 22. Export as .stl file.
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Pre-Fabrication Once an accurate mesh has been established, import the .stl file into Partworks 3D for preparation for routing.
Materials
Tools
Software
Formaldehyde-free MDF
1/4” straight wood bit Wood glue Sand paper
Partworks 3D ShopBot
CNC Routing
Tools and Materials We chose to use a 1/4” straight bit set to the specifications noted in the wiki. The molds themselves were cut on two laminates 1/2” thick formaldehyde-free MDF to achieve an overall thickness of 1” per cut. 11
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Laminate Glue (2) pieces of 1/2” thick, formaldehyde free MDF together.
Route Using the 1/4” straight bit and appropriate Shopbot settings, CNC object layers accordingly.
Cut After the route has finished, cut around the perimeter of the object, freeing the layers.
Glue & Sand Once individual layers have been freed, glue and sand layers accordingly.
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Vacuum Formed Masks: Fall 2018
Fabrication The goal of the vacuum-forming process is to heat a plastic sheet to most flexible state (ideal forming temperature). Plastic sheets will begin to transition from their more rigid state at room temperature soon after passing the glass transition temperature. Once the molds have been created, we selected three dominant plastics (LDPE, white sytrene, and black ABS) to use in the workshop. While these three were chosen, nine total option were tested and can be used. Below are the settings and results for each type of plastic. Content includes vacuum former settings, material properties and vacuum form results.
Tools
Materials
Vacuum Former Plastic sheets (as necessary) MDF Molds Elastic string Plastic clippers & cutters Plastic punch
Vacuum Formed Masks: Fall 2018
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Vacuum VacuumForming Forming Vacuum Forming Vacuum Forming Vacuum Vacuum Forming Forming Results Results from from Vacuum Vacuum Tests Tests
Type | Thickness | Workability | Recycling Code White styrene | 1/16” | Easy | 6
Results Vacuum Tests Results from Vacuum Tests Below Below arefrom are comparisons comparisons of each of each plastic plastic type type after after different different durations durations of heating of heating in the in the vacuum vacuum former. former. For For each each plastic, plastic, the the firstfirst testtest waswas a length a length of two of two minutes minute Results Results from from Vacuum Vacuum Tests Tests Below comparisons of each Below plastic type comparisons after ofamount durations each ofdepending heating type after and and theare the second second testtest waswas either either for aforshorter a are shorter or longer ordifferent longer amount of plastic time, of time, dependi in the vacuum former. For each plastic, in the vacuum the first former. test was For a each length plastic, of two the minutes first te on material on material response. response. Below Below are comparisons comparisons each of each plastic type after after different different durations durations heating of heating and theare second test wasofeither for and aplastic shorter thetype second or longer test was amount either offor time, a of shorter depending or lon in the in the vacuum vacuum former. former. For For each each plastic, plastic, the the first first testtest waswas a length a length of two of two minutes minute on material response. on material response. For For our our workshop, workshop, we we used used white white styrene, styrene, black black ABS, ABS, andand LDPE. LDPE. andand the the second second testtest waswas either either for aforshorter a shorter or longer or longer amount amount of time, of time, depending depend on material on response. response. For ourmaterial workshop, we used whiteFor styrene, our workshop, black ABS, weand used LDPE. white styrene, black A For For our our workshop, workshop, we we used used white white styrene, styrene, black black ABS, ABS, andand LDPE. LDPE.
- Vacuum former power settings: 80-90% power - Vacuum former heat time: 30-60 seconds. - Glass transition temperature: 94C / 200F - Ideal forming temperature: 150- 175C / 300-350F white white styrene styrene - 1 minute - 11 minute. minute White styrene
whitewhite styrene styrene - 2 minutes - 2 minutes White styrene 2 minutes.
white styrene - 1 minute
whitewhite styrene styrene - 2 minutes - 1 minute
Black ABS | 1/16” | Easy | 7
whitewhite styrene styrene - 1 minute - 1 minute
whitewhite styrene styrene - 2 minutes - 2 minutes
- Vacuum former power settings: 80-90% power - Vacuum former heat time: 30-60 seconds. - Glass transition temperature: 88 -120C / 190 - 250F - Ideal forming temperature: 150 - 180C / 300 - 356 F
blackblack ABS ABS - 2 minutes - 2 minutes
blackblack ABS ABS - 3 minutes - 3 minutes
black ABS - 21 minutes Black ABS minute.
blackblack ABS ABS - 3ABS minutes - 2 2minutes Black minutes.
blackblack ABS ABS - 2 minutes - 2 minutes
blackblack ABS ABS - 3 minutes - 3 minutes
LDPELDPE - 1 minute - 1 minute
LDPELDPE - 2 minutes - 2 minutes
LDPE - 1 minute
LDPELDPE - 2 minutes - 1 minute
white styren
black ABS -
LDPE | 1/16” | medium | 4 - Vacuum former power settings: 60-70% power - Vacuum former heat time: 30-120 seconds. - Glass transition temperature: 94C / 200F - Ideal forming temperature: 105 - 118C / 221 - 239 F
LDPE minute. LDPE LDPE - 1 minute - 1 minute
LDPE - 2 m
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LDPE minutes. LDPELDPE - 2 minutes - 22 minutes
15 Vacuum Forming Vacuum Forming 15
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Cast acrylic | 1/8” | Medium | 7 - Vacuum former power settings: 60-70% power - Vacuum former heat time: 120-240 seconds. - Glass transition temperature: 105 / 220F - Ideal forming temperature: 140 - 190C / 280 - 375 F cast acrylic - 2 1minutes Cast acrylic minute.
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Vacuum Formed Masks: Fall 2018
cast acrylic - 3 minutes cast acrylic - 2 2minutes Cast acrylic minutes.
cast acrylic
Vacuum Formingcast acrylic Vacuum Formingcast acrylic cast-acrylic - 2 minutes cast acrylic - 2 minutes 3 minutes
Type | Thickness | Workability | Recycling Code
cast acrylic - 2 minutes
cast acrylic 3 minutes cast-acrylic - 2 minutes
clear PETG - 2 minutes
clear- PETG - 2 minutes clear PETG 3 minutes
cast acrylic clear PETG
PETG | 1/16” | Medium | 1 - Vacuum former power settings: 60-70% power - Vacuum former heat time: 30-120 seconds. - Glass transition temperature: 94C / 200F - Ideal forming temperature: 105 - 118C / 221 - 239 F PETG 1 minute. clear PETG - 2 minutes
PETG minutes. clear PETG 32minutes clear- PETG - 2 minutes
clear polycarbonate - 2 minutes
clear polycarbonate - 2 minutes clear polycarbonate - 3 minutes
clear PETG clear polyc
HDPE | 1/16” | Medium | 2 Vacuum former power settings: 60-70% power Vacuum former heat time: 30-120 seconds. Glass transition temperature: 94C / 200F Ideal forming temperature: 105 - 118C / 221 - 239 F
Vacuum Vacuum Forming Forming clear polycarbonate - 2 minutes HDPE- 21minutes minute. HDPE
clear polycarbonate - 3 minutes clear polycarbonate - 2 minutes HDPE minutes. - 22minutes HDPE -HDPE 4 minutes
clear polyc HDPE - 4 m
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Polypropylene | 1/16” | Medium | 5 Vacuum former power settings: 60-70% power Vacuum former heat time: 30-120 seconds. Glass transition temperature: 5C / 41F Ideal forming temperature: 150 - 180C / 300 - 356 F
Vacuum Vacuum Forming Forming HDPE - 2 minutes
HDPE -HDPE 4 minutes - 2 minutes
HDPE - 4
16white polypropylene white polypropylene white polypropylene 2 minutes - 2 minutes white polypropylene - 3 minutes minutes Polypropylene 2- 3minutes. Polypropylene 1- minute.
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PVC | 1/16” | medium | 3 - Vacuum former power settings: 60-70% power - Vacuum former heat time: 30-120 seconds - Glass transition temperature: 105 / 220F - Ideal forming temperature: 140 - 190C / 280 - 375 F grey grey - 1PVC minute - 1 minute grey - 2PVC minutes - 2 minutes whitePVC white polypropylene - 2 minutes - 2 minutesgrey whitePVC polypropylene white polypropylene - 3 minutes - 3 minutes PVC 2 minutes. PVC 1polypropylene minute.
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Vacuum Forming Vacuum Forming
Type | Thickness | Workability | Recycling Code white polypropylene white polypropylene - 2 minutes - 2 minutes white polypropylene white polypropylene - 3 minutes - 3 minutes cast acrylic - 2 minutes cast acrylic - 3 minutes cast acrylic - 2 minutes cast acrylic - 3 minutes
Grey PVC | 1/16” | medium | 3 - Vacuum former power settings: 60-70% power - Vacuum former heat time: 30-120 seconds - Glass transition temperature: 105 / 220F - Ideal forming temperature: 140 - 190C / 280 - 375 F Grey PVC 1minute minute. grey PVC grey- 1PVC - 1 minute clear PETG 2 minutes clear -PETG - 2 minutes
Grey PVC minutes. grey grey- 2PVC minutes - 22minutes clearPVC PETG 3 minutes clear -PETG - 3 minutes
Polycarbonate | 1/16” | medium / hard | 7 - Vacuum former power settings: 50-70% power - Vacuum former heat time: 30-120 seconds. - Glass transition temperature: 150C / 300F - Ideal forming temperature: 170 - 205C / 340 - 400 F white acrylic white acrylic - 2 minutes - 2 minutes white acrylic white acrylic - 3 minutes - 3 minutes Polycarbonate 2 Polycarbonate 1- 2minute. clear polycarbonate - 2 minutes clear polycarbonate clear polycarbonate - 3minutes. minutes clear polycarbonate minutes - 3 minutes
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- 2 minutes HDPE -HDPE 2 minutes
- 4 minutes HDPE HDPE - 4 minutes
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Notes for Future Workshops
Mold fabrication - CNC routing molds out of MDF is just one of the ways that this workshop has been conducted. There are many other ways of fabricating molds that could be explored such as casting a negative shape, or CNC routing using other heat-resistant materials for molds. Subject matter - The goal of this workshop is to familiarize students at the UTSOA to under-utilized technology. The 3D scanner, CNC router and vacuum former can be utilized to fabricate a wide range of forms for different applications.
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Notes for improvement - The (2) layers of 1/2” formaldehyde-free MDF used to create the separate transverse cuts of the molds could be rethought. In order to create flush transitions between layers, the excess MDF had to be sanded down on the back of each laminate. In order to avoid this it is possible to glue (4) laminates in order to minimize sanding. - Additional means should be sought out to educate others with the types of plastics and their advantages/ disadvantages with others. - Marking the scrap plastic materials with their plastic recycle-ability number is crucial. Materials will not be recycled without the number being on it in some semi-permanent manner.
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