Transcript Prototyping ME110 Spring 2003 Product Development Process Planning Concept Development System-Level Design Detail Design Testing and Refinement Prototyping is done throughout the development process. Production Ramp-Up.

Prototyping
ME110
Spring 2003
Product Development Process
Planning
Concept
Development
System-Level
Design
Detail
Design
Testing and
Refinement
Prototyping is done throughout the development process.
Production
Ramp-Up
Spiral Model of Product Development
Determine objectives,
alternatives, constraints
Risk
Analysis
Evaluate alternatives,
identify, resolve risks
Risk
Analysis
Risk
Analysis
Risk
Analysis
Requirements
Plan
Development
Plan
Integration
and test plan
Plan next phases
Adapted from B. Boehm
Prototype 1
Concept
Requirements
Validation
Prototype
2
Prototype
3
Operational
Prototype
Simulations, models,
benchmarks
Design Validation
and Verification
Final Code Implementation
and Test
Develop, verify
Four Uses of Prototypes

Learning
–
–

Communication
–
–

demonstration of product for feedback: visual, tactile, functional
e.g., 3D physical models of style or function
Integration
–
–

answering questions about performance or feasibility
e.g., proof-of-concept model
combination of sub-systems into system model
e.g., alpha or beta test models
Milestones
–
–
goal for development team’s schedule
e.g., first testable hardware
Types of Prototypes
Physical
alpha
beta
prototype prototype
ball
support
prototype
final
product
trackball mechanism
linked to circuit
simulation
Comprehensive
Focused
simulation
of trackball
circuits
equations
modeling ball
supports
not
generally
feasible
Analytical
Physical vs. Analytical Prototypes





Physical Prototypes
Tangible approximation of the
product.
May exhibit unmodeled
behavior.
Some behavior may be an
artifact of the approximation.
Often best for communication.





Analytical Prototypes
Mathematical model of the
product.
Can only exhibit behavior
arising from explicitly
modeled phenomena.
(However, behavior is not
always anticipated.
Some behavior may be an
artifact of the analytical
method.
Often allow more
experimental freedom than
physical models.
Focused vs. Comprehensive
Prototypes




Focused Prototypes
Implement one or a few
attributes of the product.
Answer specific
questions about the
product design.
Generally several are
required.




Comprehensive
Prototypes
Implement many or all
attributes of the product.
Offer opportunities for
rigorous testing.
Often best for milestones
and integration.
Concept Prototypes Can Be
Communicated in Multiple Ways:









Verbal descriptions
Sketches
Photos and renderings
Storyboards – a series of images that communicates a
temporal sequence of actions involving the product
Videos – dynamic storyboards
Simulation
Interactive multimedia – combines the visual richness
of video with the interactivity of simulation
Physical appearance models
Working prototypes
Traditional Prototyping Methods







Model from clay
Carve from wood or styrofoam
Bend wire meshing
CNC machining (pastic or aluminum)
Rubber molding + urethane casting
Materials: wood, foam, plastics, etc.
Model making requires special skills.
Profs. Jen Mankoff and James Landay, CS
Fidelity in Prototyping


Fidelity refers to the level of detail
High fidelity
?
–

prototypes look like the final product
Low fidelity
?
–
artists renditions with many details missing
Profs. Jen Mankoff and James Landay, CS
Low-fi Storyboards for User
Interface Interactions

Where do storyboards come from?
–

film & animation
Give you a “script” of important events
–
–
leave out the details
concentrate on the important interactions
Profs. Jen Mankoff and James Landay, CS
Why Use Low-fi Prototypes?

Traditional methods take too long
–

sketches -> prototype -> evaluate -> iterate
Can simulate the prototype
–
–
sketches -> evaluate -> iterate
sketches act as prototypes



designer “plays computer”
other design team members observe & record
Kindergarten implementation skills
–
allows non-programmers to participate
Profs. Jen Mankoff and James Landay, CS
Hi-fi Prototypes Warp

Perceptions of the customer/reviewer?
–
formal representation indicates “finished” nature


Time?
–
encourage precision


comments on color, fonts, and alignment
specifying details takes more time
Creativity?
–
lose track of the big picture
Profs. Jen Mankoff and James Landay, CS
Wizard of Oz Technique (?)

Faking the interaction. Comes from?
–
from the film “The Wizard of OZ”


Long tradition in computer industry
–

“the man behind the curtain”
prototype of a PC w/ a VAX behind the curtain
Much more important for hard to implement
features
–
Speech & handwriting recognition
Profs. Jen Mankoff and James Landay, CS
The Basic Materials for Low-fi
Prototyping of Visual UIs






Large, heavy, white paper (11 x 17)
5x8 in. index cards
Tape, stick glue, correction tape
Pens & markers (many colors & sizes)
Overhead transparencies
Scissors, X-acto knives, etc.
Profs. Jen Mankoff and James Landay, CS
Constructing the Model

Set a deadline
–


Draw a window frame on large paper
Put different screen regions on cards
–

anything that moves, changes, appears/disappears
Ready response for any customer action
–

don’t think too long - build it!
e.g., have those pull-down menus already made
Use photocopier to make many versions
Profs. Jen Mankoff and James Landay, CS
Low-fi Prototypes
ESP
High Performance Companies:




Not only verify that the final product meets
customer expectations,
But involve potential customers directly in
various stages of development and encourage
partnerships
Which allows faster cycling for customer
feedback
And creates better-suited products
Virtual Prototyping

3D CAD models enable many kinds of analysis:
–
–
–
–
–
–
–

Fit and assembly
Manufacturability
Form and style
Kinematics
Finite element analysis (stress, thermal)
Crash testing
more every year...
Simulation, Optimization
Boeing 777 Testing












Rapid design-build philosophy
100% digital CAD & 3D
modeling
Part Interference
Brakes Test
Minimum rotor thickness
Maximum takeoff weight
Maximum runway speed
Will the brakes ignite?
Wing Test
Maximum loading
When will it break?
Where will it break?
CATIA CAD Modeling & Analysis



100% digital design on
the Boeing 777
Used to discover
tolerance error early in
the design cycle
Greatly reduced the
number of design
changes and costs
Simulations of all Operations
Physical Rapid Prototyping
Methods

Build parts in layers based on CAD model.
–
–
–
–
–
–


Conceptually, like stacking many tailored pieces of cardboard
on top of one another.
SLA=Stereolithography Apparatus (Cory Hall, Prof. Carlo
Sequin)
Solid Imaging (Cory Hall, Prof. Carlo Sequin)
SLS=Selective Laser Sintering
FDM= Fused Deposition Modeling (Tour - Etcheverry Hall,
Prof. Paul Wright)
Color/Mono 3D Printing (e.g., Z-Corp) (Tour - Etcheverry Hall)
Solid Injection Molding
Others every year...
Selective Laser Sintering




Thermoplastic powder is spread
by a roller over the surface of a
build cylinder.
The piston in the cylinder moves
down one object layer thickness
to accommodate the new layer of
powder.
A laser beam is traced over the
surface of this tightly compacted
powder to selectively melt and
bond it to form a layer of the
object.
Excess powder is brushed away
and final manual finishing may be
carried out.
SLA=Stereolithography Apparatus




Builds plastic parts or objects a
layer at a time by tracing a laser
beam on the surface of a vat of a
photosensitive liquid polymer.
Photopolymer quickly solidifies
wherever the laser beam strikes
the surface of the liquid.
Repeated by lowering a small
distance into the vat and a
second layer is traced right on
top of the first.
Self-adhesive property of the
material causes the layers to
bond to one another and
eventually form a complete,
three-dimensional object after
many such layers are formed.
Prof. Carlo Séquin, CS
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
Prof. Carlo Séquin, CS
Stereolithography Evaluation





Can do intricate shapes with small holes
High precision
Moderately Fast
Photopolymer is expensive ($700/gallon)
Laser is expensive ($10’000),
lasts only about 2000 hrs.
Prof. Carlo Séquin, CS
Model  Prototype  Mold  Part
Injection-Molded Housing for ST TouchChip
Prof. Carlo Séquin, CS
Séquin’s “Minimal Saddle Trefoil”

Stereo-lithography
master
Prof. Carlo Séquin, CS
Séquin’s “Minimal Saddle Trefoil”

bronze cast, gold plated
Prof. Carlo Séquin, CS
Solid Imaging: Thermojet Printing





Technology: Multi-Jet
Modeling (MJM)
Uses plastic and wax.
Need to build a support
structures where there are
overhangs / bridges that must
be removed manually.
Resolution (x,y,z): 300 x 400 x
600 DPI
Maximum Model Size: 10 x
7.5 x 8 in (13 lb)
Prof. Carlo Séquin, CS
Solid Imaging Example

That’s how parts
emerge from the
Thermojet printer

After partial removal
of the supporting
scaffolding
Prof. Carlo Séquin, CS
9-Story Intertwined Double Toroid
Bronze investment
casting from wax original
made on 3D Systems’
“Thermojet”
Prof. Carlo Séquin, CS
Solid Imaging Evaluation







An Informal Evaluation
Fast
Inexpensive
Reliable, robust
Good for investment casting
Support removal takes some care
(refrigerate model beforehand)
Thermojet 88 parts are fragile
Prof. Carlo Séquin, CS
3D Printing: Some Key Players


Soligen: http://www.zcorp.com/
Metal and ceramic powders
for operational prototypes.
Z Corporation: http://www.zcorp.com/
Plaster and starch powders
for visualization models.
–
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.
Prof. Carlo Séquin, CS
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
Three Dimensional Printing



A layer of powder object
material is deposited at the
top of a fabrication chamber.
Roller then distributes and
compresses the powder at the
top of the fabrication
chamber.
Multi-channel jetting head
subsequently deposits a liquid
adhesive in a two dimensional
pattern onto the layer of the
powder which becomes
bonded in the areas where
the adhesive is deposited, to
form a layer of the object.
Prof. Carlo Séquin, CS
3D Printing: Z Corporation
Prof. Carlo Séquin, CS
3D Printing: Z Corporation

Digging out
Prof. Carlo Séquin, CS
Optional Curing: 30 min. @ 200ºF
Keep some powder in place
<-- Tray for
transport
Prof. Carlo Séquin, CS
3D Printing: Z Corporation
Cleaning up in the de-powdering station
Prof. Carlo Séquin, CS
3D Printing: Z Corporation
The finished part
 Zcorp,
 6”
diam.,
 6hrs.
Prof. Carlo Séquin, CS
120 Cell -- Close-up
Prof. Carlo Séquin, CS
3D Color Printing: Z Corporation
Use compressed air to blow out central hollow space.
Prof. Carlo Séquin, CS
3D Color Printing: Z Corporation
Infiltrate Alkyl
Cyanoacrylane Ester =
“super-glue” to harden
parts and to intensify
colors.
Prof. Carlo Séquin, CS
What Can Go Wrong ?


Blocked glue lines
Crumbling parts
3D Printing (Z Corporation)
Evaluation





Fast !
Running expenses: moderate,
(but overpriced powder)
Color print head and tubes need
some care in maintenance.
Somewhat messy cleanup !
Lot’s of dust everywhere ...
Fused Deposition Modeling




ABS Plastic* is supplied (as
beads or filament) to an
extrusion nozzle.
The nozzle is heated to melt the
plastic and has a mechanism
which allows the flow of the
melted plastic to be turned on
and off.
As the nozzle is moved over the
table in the required geometry, it
deposits a thin bead of extruded
plastic to form each layer.
The plastic hardens immediately
after being squirted from the
nozzle and bonds to the layer
below.
* acrylonitrile-butadine-styrene
Prof. Carlo Séquin, CS
Fused Deposition Modeling
Stratasys:
http://www.stratasys.com/
Prof. Carlo Séquin, CS
Looking into the FDM Machine
Prof. Carlo Séquin, CS
Layered Fabrication of Klein Bottle
Support material
Prof. Carlo Séquin, CS
Klein Bottle Skeleton (FDM)
Prof. Carlo Séquin, CS
Fused Deposition Modeling (FDM)
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 !
Prof. Carlo Séquin, CS
What Can Go Wrong ?

Black blobs

Toppled
supports