CHS UCB CS 294-12 -- October 2002 Rapid Prototyping and its Role in Design Realization Carlo H.

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Transcript CHS UCB CS 294-12 -- October 2002 Rapid Prototyping and its Role in Design Realization Carlo H.

CHS
UCB
CS 294-12 -- October 2002
Rapid Prototyping
and its Role in
Design Realization
Carlo H. Séquin
EECS Computer Science Division
University of California, Berkeley
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UCB
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?
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DESIGN
The following questions should be raised
and be answerable:
 What
is the purpose of the artifact ?
 What
are the designer’s goals for it ?
 How
will the artifact be evaluated ?
 What
 How
are the associated costs ?
can we maximize the benefit/cost ratio ?
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Example Task
“Design an Instrument as an Interface
to 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.
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Design is an Iterative Process
Formal Specifications
Detailed Description
Clear Concept
Experiments,
get feedback
Vague idea
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.
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Conceptual Prototyping
The Traditional Options:
 Model
from clay
 Carve
from wood
 Bend
wire meshing
from styrofoam – perhaps with
surface reinforcement
 Carve
 Mill
from a block of plastic or aluminum
(3- or 4-axes machines)
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“Hyperbolic Hexagon II” (wood)
Brent Collins
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Brent Collins’ Prototyping Process
Armature for the
"Hyperbolic Heptagon"
Mockup for the
"Saddle Trefoil"
Time-consuming ! (1-3 weeks)
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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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Slices through “Minimal Trefoil”
50%
30%
23%
10%
45%
27%
20%
5%
35%
25%
15%
2%
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“Heptoroid”
( from Sculpture Generator I )
Cross-eye stereo pair
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Profiled Slice through the Sculpture

One thick slice
thru “Heptoroid”
from which Brent
can cut boards
and assemble a
rough shape.
Traces represent:
top and bottom,
as well as cuts
at 1/4, 1/2, 3/4
of 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
“Heptoroid”
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
Collaboration by
Brent Collins &
Carlo Séquin
(1997)
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Some Commercial Processes
Additive Methods with Sacrificial Supports:
 Fused
Deposition Modeling (Stratasys)
 Solidscape
 Solid
(Sanders Prototype, Inc.)
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:
of semi-liquid ABS* plastic get
deposited by a head moving in x-y-plane.
 Beads
 Supports
are built from a separate nozzle.
Schematic view ==>
 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
 Could
and robust
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 Player:
Solidscape*: http://www.solid-scape.com/
* 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
 Key
need to be removed (manually).
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

That’s how parts
emerge from the
Thermojet printer
 After
partial removal
of the supporting
scaffolding
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9-Story Intertwined Double Toroid
Bronze
investment
casting
from
wax original
made on
3D Systems’
“Thermojet”
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SFF: Solid Imaging
An Informal Evaluation
 Fast
 Inexpensive
 Reliable,
 Good
robust
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
 This
bed of powder acts as support.
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 powders
for operational prototypes.
 Therics
Inc.: http://www.therics.com/
Biopharmaceutical 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. @ 200ºF
Keep some powder in place
<-- 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
 Lot’s
messy cleanup !
of dust everywhere ...
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SFF: Stereolithography (SLA)
 UV
laser beam solidifies the top layer
of 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
 Laser
is expensive ($700/gallon)
is expensive ($10’000),
lasts only about 2000 hrs.
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Séquin’s “Minimal Saddle Trefoil”
 Stereo-
lithography
master
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Séquin’s “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?
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Use of 3D Hardcopy
What is 3D Hardcopy good for? (cont.)
 Consumer
Electronics Design Prototypes
==> touch and feel !
 Mathematical
& Topoplogical Models
==> visualization and understanding
 Artistics
Parts & Abstract Sculptures
==> all-round visual inspection,
including light and shadows.
My goal is to inspire you to put these SFF
technologies to new and intriguing uses.
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Consumer Electronics Prototypes
Role of 3D Hardcopy -- Part 1:
Modeling 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/Fall1999TradeShow/
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Model  Prototype  Mold  Part
Injection-Molded Housing for ST TouchChip
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Geometrical / Topoplogical Models
Role of 3D Hardcopy -- Part 2:
Visualization of objects,
when 2D is not quite enough.
 Self-intersecting
 Projections
surfaces.
of 4-D polytopes.
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Single-thread Figure-8 Klein Bottle
Modeling
with SLIDE
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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 3:
Maquettes 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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Collin’s 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).
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The Most Challenging SFF Part
3rd-order 3D Hilbert Curve:

much weight

much length

no supports

only two tubeconnections
between the
two halves.
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Informal Process Ratings Matrix
Hollow
Hollow
2 Nested,
Sphere Sphere with Perforated
Drain/Vent Spheres
3D
Hilbert
Pipe
Preassembled
Gear
Mechanism
LOM
(F)
F
F
D
F
SLA
(F)
D
C
B
D
FDM
3D-P
(F)
(F)
F
A
C
A
C
C
D
B
SLS
(F)
A
A
B
B
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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 100’000 triangles
 In
.STL format.