3D Hardcopy: Converting Virtual Reality to Physical Models

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3D Hardcopy Converting Virtual Reality to
Physical Models

• Sara McMains
• Carlo Séquin
• Mike Bailey
• Rich Crawford

U.C. Berkeley
SDSC UCSD
U.T. Austin
author of these slides edited by C. H. Séquin
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How Do We Make Physical Things ?
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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.

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Conventional Manufacturing

• Subtractive
• Start with simple stock
• Remove unwanted volume
• E.g.
• Machining(NC Milling)

Delcam
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Conventional Manufacturing

• Net shape
• Start with simple stock (or powder)
• Reshape in die or mold
• E.g.
• Forging
• Molding
• Casting

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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

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How Do We Make Quickly Complex Prototypes ?
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Conventional Manufacturing

• Constructive
• Combine complex sub-units
• E.g.
• Welding

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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

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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

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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

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Layers

• 2.5-D slices through model
• Slice interior defines part geometry
• Slice complement may function as fixture and/or
  support

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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).

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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

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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)
• Solidscapes ModelMaker previously Sanders
• Subtractive
• Laminated Object Manufacturing (LOM)

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LM Industrial Applications

• Design review
• Positives for molds
• Functional testing

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LM Medical Applications

• Prosthetics
• Pharmaceuticals
• Micro-structure control
• Tissue engineering

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LM Educational Applications

• Scientific Visualization
• Topological Models
• Tactile Mathematics

San Diego Harbor (Bailey)
Hyperbolic parabaloid w/ Braille annotations
(Stewart Dickson)
Klein Bottle Skeleton (Séquin)
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LM Artistic Applications

• Jewelry
• Sculpture

Ora Squared (Bathsheba Grossman)
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CAD/RP Courses Use of LM

• Scientific Parts
• Math Models
• Beautiful Artifacts
• Fun Stuff !