Rapid Prototyping
Laminated Object Manufacturing
Selective Laser Sintering
Stereolithography
Fused Deposition Modeling
Solid Ground Curing
3D Printing
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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
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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
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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
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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
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Polymers
Paper
Wax
Powdered Metal
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Clean and Finish
• Final Step is post-processing
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Removing prototype
Detaching supports
Curing (if needed)
Minor Cleaning
Surface treatment
• Sanding, sealing, painting and so on
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Clean and Finish
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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
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LOM Process
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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.
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SLS Process
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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
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SLA Examples
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SLA Examples Cont…
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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
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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…
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3D Printing Examples Cont…
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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.h
tml
• 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
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Source Credit Cont.
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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
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