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1
Rapid Prototyping
Laminated Object Manufacturing
Selective Laser Sintering
Stereolithography
Fused Deposition Modeling
Solid Ground Curing
3D Printing
2
What is Rapid Prototyping
• Builds parts Layer-By-Layer
• Class of technologies that construct physical models from CAD data
• Some what like a 3-D printer
• An Additive process
• Visual Aids or Design Testing
• Rapid Tooling or Rapid Production of parts
3
The Basic Process
• Create a CAD model of the design
• Convert the CAD model to STL format
• Slice the STL file into thin cross-sectional layers
• Construct the model one layer atop another
• Clean and finish the model
4
CAD MODEL
• Build a Model
• Solid Modeler Packages– Such as Pro-Engineer tend to represent objects
more accurate then wire frame packages– Yield better results
• Existing CAD or Create a model for RP
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Conversion to STL
• STL Format– Establish consistency
– ****.stl – stereolithography, the first RP technique
– Represents a 3-D surface in an assembly of planar triangle
• Like facets of a cut jewel
• Planar elements– Can not represent curve surfaces exactly
– Accuracy vs. manageability
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Conversion to STL
7
The Slice
• Pre-processing program– Prepares STL file for build– Most program allows user to adjust the model
• Size
• Location
• Orientation
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The Slice
• Orientation– Weaker and less accurate in the Z direction then
in the x-y plane– Orientation partially determines the amount of
time for build• Higher in the Z – lot more time to build
• Place shortest dimension in the Z– Reduces the number of layers
– Layers are slices from .01mm to .7 mm (technique)
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The Slice
• Auxiliary Structure– Supports the model during build– Useful for delicate parts– Some time difficult to remove
• Damage to Model
• Poor surface finish
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Layer by Layer
• Construction of the part– Several Techniques– Builds part one layer at a time
• Polymers
• Paper
• Wax
• Powdered Metal
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Clean and Finish
• Final Step is post-processing– Removing prototype– Detaching supports– Curing (if needed)– Minor Cleaning– Surface treatment
• Sanding, sealing, painting and so on
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Clean and Finish
13
Rapid Prototyping Techniques
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Laminated Object Manufacturing
• Called LOM. (Helisys)• Paper is coated heat-activated glue so it will stick.
(spool)• Paper is bonded with last piece with heated rollers.• Design is cut out of paper with a laser.• The excess paper is cross hatched for removal.• Produces large parts.
– Wood like texture
15
LOM Process
16
LOM Examples
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Selective Laser Sintering
• Called SLS. (DTM – Carl Deckard)
• Melts powdered material a layer at a time.– Uses leveling rollers
• Laser is used to melt powdered material.– Traces part and sintering metal powder
• Makes functional parts.
• Many different powders can be used.
18
SLS Process
19
SLS Examples
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Stereolithography
• Called SLA. (3D Systems –first 1986)• Photosensitive liquid resin hardens when
exposed to a laser.– Low-power high focused UV laser– Traces out layer, solidifying resin– Liquid epoxy or acrylate resin
• The part is created layer by layer.• The part needs to be cured after it is
created.• Great accuracy and surface finish.
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SLA Process
22
SLA Examples
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SLA Examples Cont…
24
Fused Deposition Modeling
• Second Most Widely Used• Filament of heated thermoplastic is extruded from the
tip• X-Y plane• Like decorating a cake• Platform lowered and head deposits a second layer
upon the first• ABS, PC, Casting Wax, Polyphenolsulfone
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FDM SAMPLES
26
Solid Ground Curing
• SGC - (Cubical)• Similar to stereolithography• Uses UV light
– Selectively hardens photosensitive polymers
– Cures entire process at a time
• Photomask– Printed on glass plate
– UV light passes through the mask to the polymer
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SGC
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3D Jet Printing
• Entire class of machines– 3D Printing (3DP – MIT, Soligen Corp.)
• Powder (excess is blown off)
– ZCORP 3D (Z corp.)• Powder (excess is blown off)
– Thermo-Jet (3D systems)• Molten wax or polymer (no excess)
• The model is built up layer upon layer at a time.– Ink-jet printer head technology
• Different materials can be used.• Versatile
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3D Printing Process
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3D Printing Examples
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3D Printing Examples Cont…
32
3D Printing Examples Cont…
33
Source Credit
• http://home.att.net/~castleisland/lom_int.htm • http://www.milparts.net/lom.html
• http://www.ind.tno.nl/prototyping/rapid_prototyping/lom.html
• http://www.bath.ac.uk/~en7bnd/rp/lom.htm
• http://home.att.net/~castleisland/sls_int.htm
• http://www.materialise.com/mt.asp?mp=ps_laser • http://www.cs.hut.fi/~ado/rp/subsection3_6_3.html
34
Source Credit Cont.
• http://www.cs.hut.fi/~ado/rp/subsection3_6_1.html
• http://www.padtinc.com/rm/sla/default.htm
• http://www.webworqs.com/nomura/stereo.html
• http://www.howstuffworks.com/stereolith3.htm
• http://www.nsf.gov/od/lpa/news/02/3dprinttip_images.htm
• http://web.mit.edu/tdp/www/whatis3dp.html
• http://web.mit.edu/tdp/www/applications.html
• http://www.zcorp.com/content/product_info/keyadvantages.html