Product, Project, and Decision Risk
9.2 BOMs
2459.3 Form Generation
2469.4 Materials and Process Selection
2649.5 Vendor Development
2669.6 Generating a Suspension Design for the
Marin 2008 Mount Vision Pro Bicycle 2699.7 Summary
2769.8 Sources
2769.9 Exercises
2779.10 On the Web
278 CHAPTER 10 Product Evaluation for Performance and the Effects of Variation 279 10.1 Introduction 279 10.2 Monitoring Functional Change 280 10.3 The Goals of Performance Evaluation 281 10.4 Trade-Off Management 28410.5 Accuracy, Variation, and Noise
28610.6 Modeling for Performance Evaluation
29210.7 Tolerance Analysis
29610.8 Sensitivity Analysis
30210.9 Robust Design by Analysis
30510.10 Robust Design Through Testing
30810.11 Summary
313 10.12 Sources 313 10.13 Exercises 314 CHAPTER 11 Product Evaluation: Design For Cost, Manufacture, Assembly, and Other Measures 315 11.1 Introduction 31511.2 DFC—Design For Cost
31511.3 DFV—Design For Value
32511.4 DFM—Design For Manufacture
32811.5 DFA—Design-For-Assembly
Evaluation 32911.6 DFR—Design For Reliability
35011.7 DFT and DFM—Design For Test and
Maintenance 35711.8 DFE—Design For the Environment
35811.9 Summary
36011.10 Sources
361 11.11 Exercises 361 11.12 On the Web 362 CHAPTER 12 Wrapping Up the Design Process and Supporting the Product 363 12.1 Introduction 363 12.2 Design Documentation and Communication 36612.3 Support
36812.4 Engineering Changes
37012.5 Patent Applications
37112.6 Design for End of Life
37512.7 Sources
37812.8 On the Web
378 x Contents APPENDIX A Properties of 25 Materials Most Commonly Used in Mechanical Design 379 A.1 Introduction 379 A.2 Properties of the Most Commonly Used Materials 380 A.3 Materials Used in Common Items 393 A.4 Sources 394 APPENDIX B Normal Probability 397 B.1 Introduction 397 B.2 Other Measures 401 APPENDIX C The Factor of Safety as a Design Variable 403 C.1 Introduction 403 C.2 The Classical Rule-of-Thumb Factor of Safety 405 C.3 The Statistical, Reliability-Based, Factor of Safety 406 C.4 Sources 414 APPENDIX D Human Factors in Design 415 D.1 Introduction 415 D.2 The Human in the Workspace 416 D.3 The Human as Source of Power 419 D.4 The Human as Sensor and Controller 419 D.5 Sources 426 Index 427Parts
» Mechanical engineering design process
» Introduction Measuring the Design Process with Product
» The History of the Design Process The Life of a Product
» The Many Solutions for Design The Basic Actions of Problem Solving
» Summary Mechanical Design Languages
» Different Types of Mechanical Constraints, Goals, and
» Product Decomposition Summary Introduction
» The Individual Designer: A Model of Human Mental Processes That Occur
» Characteristics of Creators The Structure of Design Teams
» Building Design Team Performance Overview of the Design Process
» Designing Quality into Products Product Discovery
» Choosing a Project Summary Sources Exercises On the Web
» Product, Project, and Decision Risk
» In engineering design, the designer uses three types of knowledge: knowl-
» A design process that results in a quality product can be learned, provided
» Improved material on project planning.
» Insist on rights of humanity and nature to coexist
» Recognize interdependence. On the Web
» Accept responsibility for the consequences of design
» Create safe objects of long-term value.
» Eliminate the concept of waste.
» Rely on natural energy flows.
» Understand the limitations of design.
» Seek constant improvement by the sharing of knowledge.
» Respect relationships between spirit and matter.
» Engineering Changes Patent Applications Design for End of Life Sources Placing a piece in a puzzle
» Decompose a simple system such as a home appliance, bicycle, or toy into its assemblies,
» For the device decomposed, list all the important features of one component.
» Select a fastener from a catalog that meets these requirements:
» Sketch at least five ways to configure two passengers in a new four-wheeled commuter
» You are a designer of diving boards. A simple model of your product is a cantilever beam.
» Find five examples of mature designs. Also, find one mature design that has been recently
» Teams develop decisions by consensus rather than by authority. This leads to
» Beneficial team behaviors. Well-defined decision process.
» Use of sound generationevaluation approach.
» Standardizes, organizes, and controls operations.
» Provides for consistent dissemination of information.
» Encourages improvement. Team nam
» Generate alternatives Team nam
» Identify criteria importance Team nam
» Based on the evaluation results, decide what to do next. This decision will
» “What I want for myself out of this.” Refine criteria.
» Refine evaluation—work to gain consensus and reduce uncertainty.
» Choose an alternative—you’ve made a decision, document it and address
» Develop a list of original design problems that you would like to do at least 3. Choose
» Make a list of features you don’t like about products you use. One way to develop this
» Executive summary: Team Members:
» Gantt chart: All diagrams, figures, and tables should be accurately and clearly labeled
» References: Appendices: All diagrams, figures, and tables should be accurately and clearly labeled
» For the features of the redesign problem Exercise 4.2 develop a plan as in Exercise 5.1.
» Develop a plan for making a breakfast consisting of toast, coffee, a fried egg, and juice. Be
» Developing the specifications or goals for the product
» Finding out how the specifications measure the customers’ desires
» Determining how well the competition meets the goals
» Developing numerical targets to work toward
» The QFD method can be applied to the entire problem and any subprob-
» Both competitors have good lifting position when transferring the passenger
» Both products have poor stability. Clearly, this is a market opportunity.
» The Colub is easy to move and Delton is not, need to determine why and do
» For most of adjustment requirements, neither of the competitors score above 3,
» Each specification should measure at least one customers’ requirement at
» Each specification should be measurable. Every specification should be writ-
» The first specification “seat width relative to frame width” is not clear. What
» Two points about specifications that are in terms of “number of steps”:
» For a design problem Exercise 4.1, develop a house of quality and supporting informa-
» The interface to the jam plate. Energy flows between the trigger and the jam
» Articulate the conflicting positions or functions. Identify the needs forcing the two positions.
» Articulate the conflicting positions
» Identify the issue, the objective of the needs
» Articulate injections that can relieve the conflict while meeting the objective.
» Many of the problems that engineers face contain elements that have already
» There are predictable patterns of technological change that can be applied to
» Increase degree of an object’s segmentation
» Arrange objects so they can go into action without time loss
» Stating the overall function.
» Decomposing the overall function into subfunctions. If assumptions are needed to
» Identifying all the objects nouns used and defending their inclusion in the functional
» For the redesign problem Exercise 4.2, apply items a–c from Exercise 7.1 and also study
» Which subfunctions must remain unchanged during redesign?
» Which subfunctions if any must be changed to meet new requirements?
» Which subfunctions may cease to exist?
» For the functional decomposition developed in Exercise 7.1,
» A perpetual motion machine. In recent times the patent office has refused to consider
» Use brainstorming to develop at least 25 ideas for
» A way to fasten together loose sheets of paper.
» A device to keep water off a mountain-bike rider.
» A way to convert human energy to power a boat.
» A method to teach the design process.
» Use brainwriting to develop at least 25 ideas for
» A device to leap tall buildings in a single bound.
» Are the critical parameters identified?
» Are the safe operating latitude and sensitivity of the parameters known?
» Have the failure modes been identified?
» Does hardware exist that demonstrates positive answers to the preceding four
» Is the technology controllable throughout the product’s life cycle?
» The source of the component.
» Wheel and chain must clear frame for all deflections. Wheel should move straight up and down.
» Your body while holding a 5-kg weight straight out in front of you with your
» Maximum acceleration on a standard street
» Maximum acceleration on a 5-cm standard pothole
» Identify the critical parameters and interfaces for evaluation.
» Develop a P-diagram for each.
» Choose whether to build physical models for testing or run an analytical experiment
» Perform the experiments or analysis and develop the most robust product.
» For the redesign problem Exercise 4.2, repeat the steps in Exercise 10.1.
» You have just designed a tennis-ball serving machine. You take it out to the court, turn it
» Does your machine have an accuracy or a variation problem?
» Itemize some of the potential causes of each type of error. Consider the types of
» A new, spring-powered can opener
» A diving board for your new swimming pool
» An art nouveau shelf bracket
» From what material is the component to be machined?
» The overall dimensions are 9.46 cm 3.72 in. by 4.52 cm 77 in. in the
» The wall thickness is 3.2 mm 0.125 in..
» The number of components to be manufactured is 1 million.
» The labor hourly rate is 35.
» Find the Theoretical Minimum Number of Components. Examine each
» hr R Mechanical engineering design process
» For the product developed in response to the design problem begun in Exercise 4.1,
» For the redesign problem begun in Exercise 4.2, estimate the changes in selling price
» Estimate the manufacturing cost for a plastic injection-molded component:
» Compare the costs for manufacturing volumes of 100, 1000, 10,000, and 100,000.
» Compare the cost for a change in tolerance.
» Why does changing the material have virtually no effect on cost at low plastic
» Perform a design-for-assembly evaluation for one of these devices. Based on the results
» A simple toy fewer than 10 parts
» Read as many similar instruction manuals as you can. Many companies post
» Organize instructions into sections to make it easy to find answers. Do not
» Recruit members of the user community not familiar with the product to test
» Know your goals and your vendor’s goals. Building a strong vendor relation-
» Involve vendors early. When dealing with vendors, you cannot afford delays
» Establish relationships. It is important to have vendor partners who under-
» Communicate. Put everything in writing—responsibilities, expected sales
» Stay professional. Things go wrong in life. When they go wrong in a relation-
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