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Design Process

Design Process. Professor Richard Lee Storch IND E 494 Design in the Manufacturing Firm. Winter Quarter Expectations. Draft Proposal Presentation of Draft Proposal Final Proposal Presentation of Final Proposal Project Website. Spring Quarter Expectations. Continue Website

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Design Process

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  1. Design Process Professor Richard Lee Storch IND E 494 Design in the Manufacturing Firm

  2. Winter Quarter Expectations • Draft Proposal • Presentation of Draft Proposal • Final Proposal • Presentation of Final Proposal • Project Website

  3. Spring Quarter Expectations • Continue Website • Final Project Report • Final Project Presentation • Final Project Poster • Weekly Updates

  4. References General Design Process • Dieter, G. Engineering Design – A Materials and Processing Approach, 3rd Edition, McGraw Hill, 2000 (Mech. Eng.) • Narayanan, R. and Beeby, A. Introduction to Design for Civil Engineers, Spon Press, 2001 (Civil Eng.) • Middendorf, W. Design of Devices and Systems, Marcel Dekker, 1998 (Elec. Eng.) • Groover, M. Automation, Production Systems, and Computer-Integrated Manufacturing,2nd Edition, Prentice Hall, 2001 (Ind./Manu. Eng.) • Ulrich, K. and Eppinger, S. Product Design and Development, McGraw-Hill, 2000 (Product Design)

  5. Design Definitions • Webster • ABET • Blumrich

  6. Webster • To conceive in the mind, invent • To form a plan for • To plan by making a preliminary sketch, outline, or drawing

  7. ABET The process of devising a system, component, or process to meet desired needs. It is a decision-making process (often iterative), in which basic sciences, mathematics and engineering sciences are applied to convert resources optimally to meet a stated objective. Among the fundamental elements of the design process are the establishment of objectives and criteria, synthesis, analysis, construction, testing and evaluation.

  8. Blumrich Design establishes and defines solutions to and pertinent structures for problems not solved before, or new solutions to problems which have previously been solved in a different way.

  9. Note! • Connection between planning and design • System perspective • Consideration of process and system as well as component (hardware)

  10. Webster Plan: A detailed scheme, program or method worked out beforehand for the accomplishment of an object.

  11. Industrial Process Management Cycle

  12. Product Life Cycle

  13. Pre-Market Phase • Idea Generation • Idea Evaluation • Feasibility Analysis • Technical R&D • Market R&D • Prototype • Market Testing • Commercial Production

  14. Market Phase • Product Introduction • Market Development • Rapid Growth • Increased Competition • Maturity • Decline • Abandonment

  15. Use of Technologies

  16. Design Process Systems Approach to Design Steps: • Recognition of a Need • Definition of the Problem • Gathering Information (DATA) • Development of Criteria for Evaluating Alternatives

  17. Design Process (Cont.) • Conceptualization/Formulation of Alternatives • Evaluate Alternatives • Choose Design Solution • Communication and Implementation of Design

  18. Characteristics of Design • Synthesis • Analysis--Modeling/Simplification • Iterative • Always Lacking Complete Information • Lacking Tools to Determine Optimum Solution

  19. Characteristics of Design (Cont.) • Involves compromise • Not necessary to invent or discover • Requires experience • Info Gathering • Simplification • Synthesis • Evaluation

  20. Design Process Diagram

  21. Recognition of Need Typically from Company • Many Sources—internal and external (usually the result of dissatisfaction with current situation) • Most effective when responding to customer

  22. Recognition of Need (Cont.) Common Desires • Reduce Cost • Enhance Quality/Reliability • Enhance Performance/Capabilities • Something new Response to new or developing technology

  23. Definition of Problem • Initial definition should be as broad as possible • Don’t confuse symptoms with problem • Provide a written statement—discuss and be sure there is agreement • Define the environment of the problem including systems/sub-systems • Describe/Consider constraints that limit the scope of the problem

  24. Write a formal statement INCLUDES: • Objectives and goals • Technical definition • Constraints • Initial evaluation criteria Revisit - especially following data collection • Subdivide problem statement

  25. Objectives and Goals • Musts—requirements that must be met • Must nots—constraints • Wants • Don’t wants PRIORITIZE!

  26. Data/Information Gathering Key points • Insufficient data available for some or all aspects of design • Too much data is available for some aspects • Accuracy/Validity of data uncertain • Critical data is unavailable • Sources of data vary—rarely looks like textbook data

  27. Data/Information Gathering (Cont.) • Different data types required at different stages of design • Available data is qualitative (sometimes quantitative) • Data becomes available after need—after design has progressed beyond that analysis • Time and resources for data collection limited/insufficient

  28. Responses • Carefully document data collection process • Name/Date each page • Document computer work • Flag uncertainties • Identify gaps

  29. Quote “To err is human – to fail to document is negligent.”

  30. Responses (Cont.) • Develop multiple information sources • Library • Data bases • Individual files/notes • Vendors/suppliers • Experts (external and internal)

  31. Responses (Cont.) • State Data needs early – as part of model development • Iterative Process

  32. Evaluation Criteria • Based directly on need and problem definition • Become more specific as design progresses • Multiple objectives - often in conflict - “compromises” • Must be fixed before design alternatives are finalized

  33. Evaluation Criteria (Cont.) • Use quantitative and qualitative criteria • Use “common sense” - be reasonable • Use engineering judgment • Use Sensitivity Analysis

  34. Formulate Alternatives Based on models • Descriptive • Classical scientific methods • Most engineering analysis tools • Solves/helps solve part of problem • Prescriptive models or optimization • Based on criteria • Set of constraints • ASSUMPTIONS—solves part of problem

  35. Rules of Thumb • Use many design approaches, including non-traditional • Often must complicate one part to simplify overall system problem • Subdivide the problem into a number of smaller ones • Work with the problem environment (company, people within, market, materials, capital . . .)

  36. Rules of Thumb (Cont.) • Build new developments into design—either continuous or in next iteration • Use feedback loops. Beware of NIH (Not Invented Here) • Consider new inventions, new technology (even before proof) • Establish progressive boundaries • Make and document decisions during the process

  37. Evaluation • Ongoing throughout design • Quantitative and qualitative • Apply experience, intuition, common sense, engineering judgment • Use sensitivity analysis (to reduce number of variables to be considered) • Use DOE/Use Prototype

  38. Choose • Based on evaluation criteria • Based on quantitative results, employing some qualitative ideas

  39. Communicate/Implement • Do not underestimate the importance of this step • Requires physical products • Report (written) • Presentation • Model • Test application • Training tools (varying levels) • Implementation plan should be able to respond to feedback from impacted parties

  40. Communicate/Implement (Cont.) • Identify proponents and opponents and consider their points (also proponents who silently oppose) • Do not wait to start with these people at this point - start at earliest appropriate design stage • Manage implementation • Training tools • Detailed plan • Check back

  41. Design Stages Stages ≈ Time order • Feasibility Study/Concept Design Goals: - Validate need - Identify a number of possible solutions - Evaluate at least to level of detail to assess financial and technical feasibility - Prioritize things to carry forward (each stage must be “yes” to move on)

  42. Design Stages (Cont.) • Preliminary Design • Quantify parameters looking toward optimality • Get “order of magnitude” estimates • Contract Design • Fixed cost estimate • General understanding of capability • Delivery schedule • Enough detail for subcontracting • Vendor requirements • Major material/component identification

  43. Design Stages (Cont.) • Detail Design • All detail needed to manufacture (work instruction design) • BOM • Work station instructions • Process parameters • Geometry (work sequence)

  44. Design Stages (Cont.) • Plan for manufacture • Process flow • Tools and fixtures • Work organization (line balance, cell arrangement…) • Inventory management • Material ordering • Information management

  45. Design Stages (Cont.) • Note that the ideal application of the design stages is to permit: • Direct data transfer between stages • Concurrent work between stages, where appropriate • Iteration between stages, where necessary • Consideration of the needs of succeeding stages at earlier stages • Development of increasing levels of detail at succeeding stages

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