Layered Manufacturing Technologies u Powder Solidification l 3D Printing (3DP) l Selective Laser Sintering (SLS) u Additive With Sacrificial Supports l Stereolithography (SLA) {= Liquid solidification} l Thermoplastic deposition ¡ Fused Deposition Modeling (FDM) ¡ Solid Object Printing w/ Multi-Jet Modeling (MJM) ¡ Solidscape’s ModelMaker {previously: Sanders} u “Subtractive” l Laminated Object Manufacturing (LOM)

Layered Solidification Processes Liquid-Based Approaches u Stereolithography (latest process needs almost no “supports”) Powder-Bed Based Approaches u 3D Printing (Z-Corporation) u Selective Laser Sintering

Stereolithography (SLA) u First commercial layered manufacturing technology (1988) u Photo-curable liquid resin u

Stereolithography (SLA) u UV laser beam solidifies the top layer of a photosensitive liquid. Build Stage UV Laser Beam Photopolymer

Stereolithography: Apparatus

Stereolithography Pre-process: u Orient part. u Choose slice thickness. u Slice parts and plan supports.

Stereolithography Process: u Position build platform (stage) just below liquid resin surface. u Smooth surface with re-coater blade. u Scan the outline of the current slice, loosely hatch part interior with laser. u Lower the build platform for next layer.

Stereolithography Post-process: u Raise part and drain out liquid. l (except liquid trapped by loose hatch) u Break off supports. u Rinse in isopropanol and water. u Dry with air hose. u Post-cure (strengthen) in UV oven.

Stereolithography Characteristics: u Slow process u Supports must be removed by hand u Lab environment necessary (gasses!) u Needs trained operator u Laser lasts 2000hrs, costs $20’000! u Little material choice, ($700 per gallon) u Parts can be brittle, fragile

Stereolithography Characteristics (cont.): u High accuracy l Layer thickness ” l Minimum feature size ” u Large build volume l Up to 20 x 20 x 23”

Powder-based Approaches Key Properties: u Needs no supports that must be removed! u Uniform bed of powder acts as support. u This powder gets selectively (locally) glued (or fused) together to create the solid portions of the desired part.

3D Printing -- Principle u Selectively deposit binder droplets onto a bed of powder to form locally solid parts. Powder SpreadingPrinting Build Feeder Powder Head

3D Printing: Some Key Players u Z Corporation: Plaster and starch powders for visualization models. u Soligen: Metal and ceramic powders for operational prototypes. u ProMetal: Metal sintering process for operational prototypes and art work. u Therics Inc.: Biopharmaceutical products, tissue engineering.

3D Printing: Z Corporation The Z402 3D Printer l Speed: 1-2 vertical inches per hour l Build Volume: 8" x 10" x 8" l Thickness: 3 to 10 mils, selectable

3D Printing: Z Corporation

u Digging out

Optional Curing: ºF Keep some powder in place <-- Tray for transport

3D Printing: Z Corporation Cleaning up in the de-powdering station

3D Printing: Z Corporation The finished part u Zcorp, u 6" diam., u 6 hrs.

120 Cell -- Close-up

Parallel Projection of the 4D 120-Cell u Zcorp, u 6" diam., u 6 hrs.

Morin Surface This is the half-way point of a sphere eversion (without causing creases or tears). 3D-Print 6 " diam. 5 hrs.

3D Color Printing: Z Corporation The Z402C 3D Color Printer Differences compared to mono-color printer: l Color print head with: Cyan, Yellow, Magenta, Black, and Neutral. l Smaller build area. Specs: l Speed: vertical inches per hour l Build Volume: 6" x 6" x 6" l Layer Thickness: 3 to 10 mils, selectable l Color depth: 80 mils below surface

3D Color Printing: Z Corporation

Use compressed air to blow out central hollow space.

3D Color Printing: Z Corporation Infiltrate Alkyl Cyanoacrylane Ester = “super-glue” to harden parts and to intensify colors.

3D Color Printing: Z Corporation “Lizard-Frame”: Final Infiltrated Part

Hypercube, Perspective Projections

Two Ways to Make a Hypercube 3D Color Print Assembly of flat FDM parts ==>

What Can Go Wrong ? -- Parts may brake before infiltration

What Else Can Go Wrong ? u Blocked glue lines u Crumbling parts

What Else Can Go Wrong ? u Some blocked glue lines u Uneven coloring  Art ?

Post-Processing for 3D-Printing Surface is porous, dusty.  Seal and strengthen the part: u Dip in wax: l Nice smooth finish l Needs separate waxing station u Infiltrate with “superglue”: l Tedious, dirty manual labor u Spray-paint with a sealant: l Polyurethane (yellowish, smelly) l Krylon (invisible)

Post-Processing for 3D-Printing u Spray-paint surface with Krylon

3D Printing: Z Corporation An Informal Evaluation u Fast ! u Running expenses: moderate, (but overpriced powder) u Color print head and tubes need some care in maintenance. u Somewhat messy cleanup ! u Lot’s of dust everywhere...

Key Points: u Powder gets solidified with a laser. u Powder is kept just below melting point, heat from laser will fuse powder grains. u Un-fused powder acts as support, can easily be removed later. u Many different materials can be used when mixed with a suitable binder: nylon, metal, ceramics … Selective Laser Sintering (SLS)

SLS: Conceptual View

SLS Players 3D SYSTEMS u Representing the fourth generation of SLS® (selective laser sintering) technology, Vanguard™ and Vanguard™ HS (High Speed), are the first SLS® systems developed specifically for advanced manufacturing applications. u With the Vanguard system you can move directly from a CAD file to a durable, functional plastic or metal part or tool — in a fraction of the time required for traditional machining and tooling.

SLS from 3D SYSTEMS Use Vanguard or Vanguard HS system for: Plastic or metal parts, patterns & prototypes Complex metal tooling inserts Highly Durable Parts Parts with small features Short runs of plastic & metal parts Benefits: High part accuracy Fast build speed Unattended operation Uses plastic or metal materials Respond to customer demands Worldwide service and support

SLS: Laserform Parts

The Most Challenging SFF Part 3 rd -order 3D Hilbert Curve: u much weight u much length u no supports u only two tube- connections between the two halves.

Fabricated by ProMetal

ProMetal Process u A ‘green’ part is first formed, composed of stainless steel powder and a selectively applied binder. u This part is built bottom-up, layer-by-layer under direct computer control. u This green part is then sintered, the binder is drained out and replaced by liquid bronze. u ProMetal is a division of ‘The Ex One Company’, Irwin, PA.

The Objet PolyJet Process

u Pointer to the company: u u See the movie... u

Which Process Should You Pick? Do you need a prototype (not just a model)?  SLS, FDM (for robustness, strength). Do you need a mold for a small batch?  SLA (for smooth, hard surface). Does part need multiple colors?  3D Color-Printing. Does part have convoluted internal spaces?  3D-Print, SLS, SLA (easy support removal).

Informal Process Ratings Matrix