ME 290P October 2002

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ME 290P -- October 2002

• Rapid Prototyping and its Role in Product
  Development
• Carlo H. Séquin
• EECS Computer Science Division
• University of California, Berkeley

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Design is an Iterative Process
Formal Specifications
Detailed Description
Clear Concept
Vague idea
Experiments, get feedback
Revision of artifact
1st hack'
Demo Prototype
Usable Evaluation Series
Marketable Systems Product
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A Specific Challenge

• Create as soon as possible a 3D "free-form" part
• (not a box-like thing that can be built from flat
  plates)
• for evaluation in its application context.
• This includes
• visualization
• tactile feedback
• function verification
• simulation of final use.

4
Conceptual Prototyping

• The Traditional Options
• Model from clay
• Carve from wood
• Bend wire meshing
• Carve from styrofoam perhaps with surface
  reinforcement
• Mill from a block of plastic or aluminum (3- or
  4-axes machines)

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New Ways of Rapid Prototyping

• Based on Layered Manufacturing
• Build the part in a layered fashion-- typically
  from bottom up.
• Conceptually, like stacking many tailored pieces
  of cardboard on top of one another.
• Part geometry needs to be sliced, and the
  geometry of each slice determined.
• Computer controlled, fully automated.

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What SFF exists in COE ?

• In Etcheverry
• A Fused Deposition Modeling Machine
• A Z-Corp Color/Mono 3D Printer
• In Cory Hall
• Solid Printing / Imaging (3D Systems)
• Stereolithography (3D Systems)
• You need to prepare
• A watertight boundary representation with less
  than 100000 triangles
• In .STL format.

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SFF Fused Deposition Modeling

• Principle
• Beads of semi-liquid ABS plastic get deposited
  by a head moving in x-y-plane.
• Supports are built from a separate nozzle.
• 
  Schematic view gt
• Key player Stratasys http//www.stratasys.com/
  

acrylonitrile-butadine-styrene
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Fused Deposition Modeling
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Looking into the FDM Machine
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Layered Fabrication of Klein Bottle

• Support material

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Klein Bottle Skeleton (FDM)
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Fused Deposition Modeling (FDM)

• An Informal Evaluation
• Easy to use
• Rugged and robust
• Could have this in your office
• Good transparent software (Quickslice)with
  multiple entry points STL, SSL, SML
• Inexpensive to operate
• Slow
• Think about support removal !

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What Can Go Wrong ?

• Black blobs
• Toppled supports

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SFF Solid Imaging

• Droplets of a thermoplastic material are sprayed
  from a moving print head onto a platform
  surface.
• Need to build a support structures where there
  are overhangs / bridges.
• These supports (of the same material) are given
  porous, fractal nature.
• They need to be removed (manually).
• Key player 3D Systems http//www.3dsystems.com/
  index_nav.asp

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SFF Solid Imaging
Supports made from same material, but with a
fractal structure
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SFF Solid Imaging

• Thermojet Printer (3D Systems)
• Technology Multi-Jet Modeling (MJM)
• Resolution (x,y,z) 300 x 400 x 600 DPI
• Maximum Model Size 10 x 7.5 x 8 in (13 lb)
• Material neutral, gray, black thermoplastic
• ThermoJet 88 smooth surfaces for casting
• ThermoJet 2000 more durable for handling

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SFF Solid Imaging

• Thats how partsemerge from theThermojet printer

• After partial removalof the supportingscaffoldin
  g

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9-Story Intertwined Double Toroid
Bronze investment casting from wax original
made on 3D SystemsThermojet
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SFF Solid Imaging

• An Informal Evaluation
• Fast
• Inexpensive
• Reliable, robust
• Good for investment casting
• Support removal takes some care(refrigerate
  model beforehand)
• Thermojet 88 parts are fragile

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Powder-based Approaches

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

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SFF 3D Printing -- Principle

• Selectively deposit binder droplets onto a bed
  of powder to form locally solid parts.

Head
Powder Spreading
Printing
Powder
Feeder
Build
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3D Printing Some Key Players

• Z Corporation http//www.zcorp.com/Plaster and
  starch powders for visualization models.
• Soligen http//www.zcorp.com/Metal and ceramic
  powdersfor operational prototypes.

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3D Printing Z Corporation

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

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3D Printing Z Corporation
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3D Printing Z Corporation

• Digging out

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Optional Curing 30 min. _at_ 200ºF

• Keep some powder in place

• lt-- Tray for transport

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3D Printing Z Corporation

• Cleaning up in the de-powdering station

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3D Printing Z Corporation

• The finished part

• Zcorp,
• 6 diam.,
• 6hrs.

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120 Cell -- Close-up
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3D Color Printing Z-Corporation

• The Z402C 3D Color Printer
• Differences compared to mono-color printer
• Color print head with Cyan, Yellow, Magenta,
  Black, and Neutral.
• Smaller build area.
• Specs
• Speed 0.33 - 0.66 vertical inches per hour
• Build Volume 6" x 6" x 6"
• Thickness 3 to 10 mils, selectable
• Color depth 80 mils

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3D Color Printing Z Corporation

• Use compressed air to blow out central hollow
  space.

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3D Color Printing Z Corporation

• Infiltrate Alkyl Cyanoacrylane Ester
  super-glue to harden parts and to intensify
  colors.

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What Can Go Wrong ?

• Blocked glue lines
• Crumbling parts

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Broken Parts
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3D Printing Z Corporation

• An Informal Evaluation
• Fast !
• Running expenses moderate,(but overpriced
  powder)
• Color print head and tubes need some care in
  maintenance.
• Somewhat messy cleanup !
• Lots of dust everywhere ...

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SFF Stereolithography (SLA)

• UV laser beam solidifies the top layerof a
  photosensitive liquid.

UV Laser Beam
Photopolymer
Build Stage
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SFF Stereolithography (SLA)

• SLA Machine by 3D Systems
• Maximum build envelope
  350 x 350 x 400 mm in XYZ
• Vertical resolution 0.00177 mm
• Position repeatability 0.005 mm
• Maximum part weight 56.8 kg

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Stereolithography

• An Informal Evaluation
• Can do intricate shapes with small holes
• High precision
• Moderately Fast
• Photopolymer is expensive (700/gallon)
• Laser is expensive (10000),lasts only about
  2000 hrs.

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Séquins Minimal Saddle Trefoil

• Stereo-lithography master

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Séquins Minimal Saddle Trefoil

• bronze cast, gold plated

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Consumer Electronics Prototypes

• Role of 3D Hardcopy -- Part 1Modeling and
  Prototyping
• Packaging of various electronics components.
• Custom designed housing for other utility
  products.
• The physical frame for an instrument

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Prototyping Consumer Products

• Solarcator and Contact-Compact
• Two student-designed products in ME221
• http//kingkong.me.berkeley.edu/html/gallery/Fall1
  999TradeShow/

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Model ? Prototype ? Mold ? Part

• Injection-Molded Housing for ST TouchChip

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Artistics Parts, Abstract Sculptures

• Role of 3D Hardcopy -- Part 3Maquettes for
  Visualization
• All-round inspection, including light and
  shadows.
• Parts that could not be made in any other way
• Prototyping modular parts, before an injection
  mold is made.

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Viae Globi Sculptures

• FDM maquettes of possible bronze sculptures

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Sculpture Design Solar Arch

• branches 4
• storeys 11
• height 1.55
• flange 1.00
• thickness 0.06
• rim_bulge 1.00
• warp 330.00
• twist 247.50
• azimuth 56.25
• mesh_tiles 0
• textr_tiles 1
• detail 8
• bounding box
• xmax 6.01,
• ymax 1.14,
• zmax 5.55,
• xmin -7.93,
• ymin -1.14,
• zmin -8.41

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Competition in Breckenridge, CO
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FDM Maquette of Solar Arch
? 2nd place
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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-P, SLS, SLA (easy support removal).

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Informal Process Ratings Matrix