12 prototyping
-
Upload
imran-hossain -
Category
Business
-
view
8 -
download
0
Transcript of 12 prototyping
Prototyping
Teaching materials to accompany:Product Design and Development
Chapter 14Karl T. Ulrich and Steven D. Eppinger5th Edition, Irwin McGraw-Hill, 2012.
Product Design and DevelopmentKarl T. Ulrich and Steven D. Eppinger5th edition, Irwin McGraw-Hill, 2012.
Chapter Table of Contents:1.Introduction2.Development Processes and Organizations3.Opportunity Identification4.Product Planning5.Identifying Customer Needs6.Product Specifications7.Concept Generation8.Concept Selection9.Concept Testing10.Product Architecture11.Industrial Design12.Design for Environment13.Design for Manufacturing14.Prototyping15.Robust Design16.Patents and Intellectual Property17.Product Development Economics18.Managing Projects
PlanningPlanning
Product Development Process
ConceptDevelopment
ConceptDevelopment
System-LevelDesign
System-LevelDesign
DetailDesign
DetailDesign
Testing andRefinement
Testing andRefinement
ProductionRamp-Up
ProductionRamp-Up
Prototyping is done throughout the development process.
Concept Development Process
Perform Economic Analysis
Benchmark Competitive Products
Build and Test Models and Prototypes
IdentifyCustomer
Needs
EstablishTarget
Specifications
GenerateProduct
Concepts
SelectProduct
Concept(s)
Set Final
Specifications
PlanDownstreamDevelopment
MissionStatement Test
ProductConcept(s)
DevelopmentPlan
Prototyping Example:Apple PowerBook Duo Trackball
04/18/23 6
Outline
• Definition
• Steps in prototyping decisions
• Purposes of prototypes
• Principles for choosing a prototype type
04/18/23 7
Definition• An approximation of the product
along one or more dimensions of interest.
• Physical prototypes vs. analytical prototypes
• Comprehensive (with all the attributes of a product) vs. focused
Four Uses of Prototypes• Learning
– answering questions about performance or feasibility– e.g., proof-of-concept model
• Communication– demonstration of product for feedback– e.g., 3D physical models of style or function
• Integration– 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
ComprehensiveFocused
Physical
Analytical
finalproduct
betaprototype
alphaprototype
ballsupport
prototype
simulationof trackball
circuits
equationsmodeling ball
supports
trackball mechanismlinked to circuit
simulation
notgenerallyfeasible
04/18/23 10
Purposes vs. prototype types
• Focused analytical– Learning
• Focused physical– Learning and communication
• Comprehensive physical– Learning, communication, integration, and
milestones.
04/18/23 11
Prototype decision (technical risk vs. prototype cost)• Low risk- low cost (e.g., printed matters)
– No need for comprehensive prototypes• Low risk – high cost (ships, buildings)
– Can’t afford comprehensive prototype.• High risk – low cost (software)
– Many comprehensive prototypes• High risk high cost (airplanes, satellites)
– Use analytical models extensively– Carefully planned comprehensive prototypes– Sell the first unit
Physical vs. Analytical PrototypesPhysical 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.
04/18/23 14
Principles for choosing a prototype type
• Analytical prototypes are in general more flexible than physical prototypes
• Physical prototypes are required to detect unanticipated phenomena
• Prototypes may reduce the risk of costly iterations• Prototypes may expedite other development steps
– Example: add a prototyping step in the part design-mold design-molding process
Boeing 777 TestingBrakes 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?
Comprehensive Prototypes
Cost of Comprehensive PrototypeHighLow
Tec
hn
ical
or
Mar
ket
Ris
k
Hig
hL
ow
One prototype may be used for verification.
Few or no comprehensiveprototypes are built.
Many comprehensiveprototypes are built.
Some comprehensiveprototypes build (and sold?).
Prototyping Strategy• Use prototypes to reduce uncertainty.• Make models with a defined purpose.• Consider multiple forms of prototypes.• Choose the timing of prototype cycles.
–Many early models are used to validate concepts.–Relatively few comprehensive models are
necessary to test integration.
• Plan time to learn from prototype cycles.–Avoid the “hardware swamp”.
04/18/23 18
Prototype technologies• Traditional prototyping methods• 3D computer modeling• Free-form fabrication
– Stereolithography• Using various materials including wax, resin, paper,
ceramics, and metals.
– Lamination• Using paper cut, lay by layer
– Rapid prototyping • Laser curing (solidifying) soft materials such as resin, layer
by layer
– 3D printing
Traditional Prototyping Methods
• CNC machining
• Rubber molding + urethane casting
• Materials: wood, foam, plastics, etc.
• Model making requires special skills.
Rapid Prototyping Methods
• Most of these methods are additive, rather than subtractive, processes.
• Build parts in layers based on CAD model.– SLA=Stereolithogrpahy Apparatus– SLS=Selective Laser Sintering– 3D Printing– LOM=Laminated Object Manufacturing– Others every year...
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...
BMW Virtual Crash Test
From: Scientific American, March 1999
Other Images
Prototyping
Chapter 12
EIN 6392, Product Design
summer 2012
04/18/23 43
Steps
• Define the purpose of the prototype• Establish the level of approximation of the
prototype• Outline an experimental plan• Create a schedule for procurement,
construction, and test• Plan milestones for prototypes (alpha, beta,
pre-production)