CS 29412 October 2002

1
CS 294-12 -- October 2002

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

2
Focus of Talk

• How can we use the visualization power offered
  by computer graphics and by computer-controlled
  rapid prototyping in design and in design
  realization?

3
DESIGN

• The following questions should be raisedand be
  answerable
• What is the purpose of the artifact ?
• What are the designers goals for it ?
• How will the artifact be evaluated ?
• What are the associated costs ?
• How can we maximize the benefit/cost ratio ?

4
Example Task

• Design an Instrument as an Interfaceto an
  Existing Data Base.
• Purpose Enhance access to data base.
• Goals Provide novel insights, deeper
  understanding, better user interface.
• Evaluation Let several users use the device and
  observe what emerges.
• Costs Fabrication, as well as operation.
• Optimization Heavily dependent on approach taken.

5
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
6
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.

7
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)

8
Hyperbolic Hexagon II (wood)
Brent Collins
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Brent Collins Prototyping Process
Mockup for the "Saddle Trefoil"
Armature for the "Hyperbolic Heptagon"
Time-consuming ! (1-3 weeks)
10
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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Slices through Minimal Trefoil
50
10
23
30
45
5
20
27
35
2
15
25
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Heptoroid ( from Sculpture Generator I )
Cross-eye stereo pair
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Profiled Slice through the Sculpture

• One thick slicethru Heptoroidfrom which Brent
  can cut boards and assemble a rough
  shape.Traces represent top and bottom,as
  well as cuts at 1/4, 1/2, 3/4of one board.

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Emergence of the Heptoroid (1)
Assembly of the precut boards
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Emergence of the Heptoroid (2)
Forming a continuous smooth edge
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Emergence of the Heptoroid (3)
Thinning the structure and smoothing the surface
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Heptoroid

• Collaboration byBrent Collins Carlo
  Séquin(1997)

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Some Commercial Processes

• Additive Methods with Sacrificial Supports
• Fused Deposition Modeling (Stratasys)
• Solidscape (Sanders Prototype, Inc.)
• Solid Printing / Imaging (3D Systems)
• Stereolithography
• Powder-Bed Based Approaches
• 3D Printing (Z-Corporation)
• Selective Laser Sintering

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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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Zooming into the FDM Machine
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Single-thread Figure-8 Klein Bottle
As it comes out of 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

• 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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Solid Object Printing

• ModelMaker II (Solidscape)

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SFF Solid Object Printing

• ModelMaker II (Solidscape)
• Alternate Deposition / Planarization Steps
• Build envelope 12 x 6 x 8.5 in.
• Build layer 0.0005 in. to 0.0030 in.
• Achievable accuracy /- 0.001 in. per inch
• Surface finish 32-63 micro-inches (RMS)
• Minimum feature size 0.010 in.
• Key PlayerSolidscape http//www.solid-scape.co
  m/
• formerly Sanders

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SFF Solid Object Printing
(2 diam.)

• Projection of 4D 120-cell, made in jewelers wax.

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SFF Solid Scape (Sanders)

• An Informal Evaluation
• The most precise SFF machine around
• Very slow
• Sensitive to ambient temperature
• Must be kept running most of the time
• Poor software
• Little access to operational parameters

Based on comments by B. G. http//www.bathsheba.
com/
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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.
• Therics Inc. http//www.therics.com/Biopharmaceu
  tical products,tissue engineering.

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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
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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 ...

55
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

57
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.

58
Séquins Minimal Saddle Trefoil

• Stereo-lithography master

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Séquins Minimal Saddle Trefoil

• bronze cast, gold plated

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Minimal Trefoils -- cast and finished by Steve
Reinmuth
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What Can SFF Be Used For?
62
Use of 3D Hardcopy

• What is 3D Hardcopy good for? (cont.)
• Consumer Electronics Design Prototypesgt touch
  and feel !
• Mathematical Topoplogical Modelsgt
  visualization and understanding
• Artistics Parts Abstract Sculpturesgt
  all-round visual inspection, including
  light and shadows.
• My goal is to inspire you to put these SFF
  technologies to new and intriguing uses.

63
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

64
Prototyping Consumer Products

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

65
Model ? Prototype ? Mold ? Part

• Injection-Molded Housing for ST TouchChip

66
Geometrical / Topoplogical Models

• Role of 3D Hardcopy -- Part 2 Visualization of
  objects, when 2D is not quite enough.
• Self-intersecting surfaces.
• Projections of 4-D polytopes.

67
Single-thread Figure-8 Klein Bottle
Modelingwith SLIDE
68
Triply-Twisted Figure-8 Klein Bottle
FDM, 9 diam.
6 days
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Projections of Reg. 4D Polytopes

• 4D Cross-Polytope

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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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Family of Scherk-Collins Trefoils
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Viae Globi Sculptures

• FDM maquettes of possible bronze sculptures

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Brent Collins at Bridges 2000
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Photos by Brent Collins
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Collins Construction Description
SWEEP CURVE (FOR DOUBLE CYLINDER) IS COMPOSED OF
4 IDENTICAL SEGMENTS, FOLLOWS THE SURFACE OF A
SPHERE.
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Reconstruction / Analysis (v1)
FROM THE FDM MACHINE
AWKWARD ALIGNMENT
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Further Explorations (v2 add twist)
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A More Complex Design (v3)
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Verification with 3D Model (v4)
GALAPAGOS-4
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Fine-tuned Final(?) Version (v5)
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Galapagos-6 in the Making
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Galapagos-6 (v6)
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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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We Can Try Again in L.A.
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Whirled White Web

• Design for the 2003 International Snow Sculpture
  Championship Breckenridge, CO, Jan.28 Feb.2

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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).

89
The Most Challenging SFF Part

• 3rd-order 3D Hilbert Curve
• much weight
• much length
• no supports
• only two tube-connectionsbetween the two
  halves.

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Informal Process Ratings Matrix
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How Can You Get Access to SFF ?

• We have under our control
• A Fused Deposition Modeling Machine
• A Z-Corp Color/Mono 3D Printer
• You need to prepare
• A watertight boundary representation with less
  than 100000 triangles
• In .STL format.