3D Hardcopy: Converting Virtual Reality to Physical Models

1. 3D Hardcopy: Converting Virtual Reality to Physical Models } U.C. Berkeley Sara McMains* Carlo Séquin Mike Bailey Rich Crawford SDSC & UCSD U.T. Austin *author of these slides – edited by C. H. Séquin

2. How Do We Make Physical Things ?

3. Main Types ofManufacturing • 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.

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

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

6. 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

7. How Do We Make Quickly Complex Prototypes ?

8. Conventional Manufacturing • Constructive • Combine complex sub-units • E.g. • Welding

9. 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

10. 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

11. 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

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

13. Supports: - Plan A • Allcomplement 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).

14. 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

15. 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)

16. LM Industrial Applications • Design review • Positives for molds • Functional testing

17. LM Medical Applications • Prosthetics • Pharmaceuticals • Micro-structure control • Tissue engineering

18. LM Educational Applications • Scientific Visualization • Topological Models • Tactile Mathematics San Diego Harbor (Bailey) Hyperbolic parabaloid w/ Braille annotations (Stewart Dickson) Klein Bottle Skeleton (Séquin)

19. LM Artistic Applications • Jewelry • Sculpture “Ora Squared” (Bathsheba Grossman)

20. CAD/RP Courses – Use of LM • Scientific Parts • Math Models • Beautiful Artifacts • Fun Stuff !