3D Hardcopy: Converting Virtual Reality to Physical Models

3D Hardcopy: Converting Virtual Reality to Physical Models

Sara McMains*Carlo SéquinMike Bailey

Rich Crawford

U.C. BerkeleyU.C. Berkeley}

U.T. AustinU.T. Austin

SDSC & UCSDSDSC & UCSD

*author of these slides – edited by C. H. Séquin

How Do We Make Physical Things ?How Do We Make Physical Things ?

Main Types of ManufacturingMain 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 ManufacturingConventional Manufacturing

• Subtractive– Start with simple stock– Remove unwanted volume– E.g.

•Machining(NC Milling)

Delcam

Conventional ManufacturingConventional 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 …

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 ?How Do We Make Quickly Complex Prototypes ?

Conventional ManufacturingConventional 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) }

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 CharacteristicsLayered 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 LayersBenefits 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

LayersLayers

• 2.5-D slices through model– Slice interior defines part geometry– Slice complement may function as

fixture and/or support

Supports: - Plan ASupports: - 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 BSupports: - 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. )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

Hyperbolic parabaloid w/ Braille annotations (Stewart Dickson)

Klein Bottle Skeleton (SéquinSéquin)

San Diego Harbor (BaileyBailey)

LM Artistic Applications

– Jewelry– Sculpture

“Ora Squared” (Bathsheba Grossman)

CAD/RP Courses – Use of LM

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