3D Hardcopy:
Converting Virtual
Reality to Physical
Models
Sara McMains*
U.C. Berkeley
Carlo Séquin
SDSC & UCSD
Mike Bailey
U.T. Austin
Rich Crawford
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*author of these slides – edited by C. H. Séquin
How Do We Make
Physical Things ?
Main Types of
Manufacturing
• Subtractive
- remove material selectively from stock.
• Net shape
- re-form material into new shape.
• Additive
- build up material in chosen locations.
• Constructive
- combine separately formed shapes.
Conventional
Manufacturing
• Subtractive
– Start with simple stock
– Remove unwanted volume
– E.g.
•Machining
(NC Milling)
Delcam
Conventional
Manufacturing
• Net shape
– Start with simple stock (or powder)
– Reshape in die or mold
– E.g.
•Forging
•Molding
•Casting
Manufacturing by
casting, stamping,
NC machining …
• Appropriate for production runs
– Incremental costs low
• Not appropriate for small batch sizes
or prototyping
– Complex process planning
– Special purpose tooling
– Set-up costs high
– Long lead times
How Do We Make Quickly
Complex Prototypes ?
Conventional
Manufacturing
• Constructive
– Combine complex sub-units
– E.g.
•Welding
Layered Manufacturing (LM)
a.k.a. Solid Freeform Fabrication (SFF)
{ a.k.a. Rapid Prototyping (RP) }
• Additive
- build-up of complex 3D shapes from 2.5D layers
Layered Manufacturing
Characteristics
• Perfect for prototyping
• Automated process planning
based on CAD model
– Short lead times
• No special purpose tooling
• Highly complex parts economical
at low production numbers
Benefits of Layers
Layering the manufacturing process
eliminates constraints:
• No tool clearance constraints:
– “Tool” is end of laser beam,
– or a drop of glue.
• No mold releasability constraints:
– Can make overhangs and undercuts.
• No fixture planning constraints:
– As long as shape hangs together
Layers
• 2.5-D slices through model
– Slice interior defines part geometry
– Slice complement may function as
fixture and/or support
Supports: - Plan A
• All complement geometry on layer
serves as support, e.g.:
– Same material in unbound form:
(non-glued or un-fused powder).
– Same material with weaker structure:
(fractal-like support pillars).
– Fill in with different sacrificial material:
(which can be removed with solvent).
Supports: - Plan B
• Supports with planned geometry
– Identify overhanging features
• Top-down, layer-by-layer analysis.
– Selectively build supports beneath
• Also layer by layer.
– May use same material as for part
• Less dense fractal like pillars
• Loose, brittle support sheets
– May use material different from part
• Remove with selective solvent
LM Technologies
( Commercial – U.S.A. )
• Powder solidification
– 3D Printing (3DP)
– Selective Laser Sintering (SLS)
• Additive with sacrificial supports
– Stereolithography (SLA) {= Liquid solidification}
– Thermoplastic deposition
• Fused Deposition Modeling (FDM)
• Solid Object Printing w/ Multi-Jet Modeling (MJM)
• Solidscape’s ModelMaker {previously: Sanders}
• “Subtractive”
– Laminated Object Manufacturing (LOM)
LM Industrial Applications
– Design review
– Positives for molds
– Functional testing
LM Medical Applications
– Prosthetics
– Pharmaceuticals
• Micro-structure control
– Tissue engineering
LM Educational Applications
– Scientific Visualization
– Topological Models
– Tactile Mathematics
San Diego Harbor
(Bailey)
Hyperbolic parabaloid w/ Braille
annotations (Stewart Dickson)
Klein Bottle Skeleton (Séquin)
LM Artistic Applications
– Jewelry
– Sculpture
“Ora Squared”
(Bathsheba Grossman)
CAD/RP Courses – Use of LM
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Scientific Parts
Math Models
Beautiful Artifacts
Fun Stuff !