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Configuration Design

Configuration Design. What is a product configuration? What is a part configuration? Product architecture design Part configuration design Evaluating Configurations Computer Aided Design Solid modeling. What is configuration design?. For example:

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Configuration Design

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  1. Configuration Design • What is a product configuration? • What is a part configuration? • Product architecture design • Part configuration design • Evaluating Configurations • Computer Aided Design • Solid modeling

  2. What is configuration design? For example: Design problem: reducespeed ---- Concept: gear pair Physical principle geometry & material embodiment What are some possible “configurations” for a gear pair?

  3. Alternative configuration #1 arrange parts differently

  4. Alternative configuration #2 Spur gears Helical gears use different features or parts

  5. wide teeth similar diameters Configuration #3 and #4 use different relative dimensions

  6. What is a part configuration? For example: Design problem: support vertical load ---- Concept: wall bracket Physical principle geometry & material embodiment What are some possible “configurations” for a wall bracket?

  7. different features alternative arrangements different relative dimensions Wall bracket configurations Abstract embodiment

  8. Change one or more of these… Configuration decisions memorize How do we create different configurations?

  9. Obtaining the “best” configuration To choose the “best” alternative…. Implies that we have a number of feasible alternatives! To be selective, we need a selection! How should we start our configuration design efforts?

  10. Establish functional requirements Determine constraints Set performance targets Formulating Problem Design specifications Create alternative forms (shape, configuration, size, materials, manufacturing processes) Generating Alternatives Redesign iteration all alternatives Analyzing Alternatives feasible alternatives Evaluating Alternatives best alternative design candidate Manufacturing specifications Use the design process as a guide?

  11. Best concept(s) Configuration design Product architecture Integral / modular Standard / special purpose Configure Product Generate Re-examine EDS Research sources Configuration requirements sketch Configure Part(s) Iterate Design for Function Design for Assembly Design for Manufacture Analyze and Refine Pugh’s Method Weighted Rating Method Evaluate Best configuration(s)

  12. Product architecture …like house architecture Rooms are arranged according to a logical “scheme.” Before the details of all the house are designed we determine the general layout or “architecture.”

  13. penlight bulb battery body screw cap switch glass lens filament base anode cathode electrolyte plastic cover case spring Recall: penlight component decomp. diagram elements are arranged into “physical building blocks”

  14. Product Standard Part Special purpose Part Subassembly A Subassembly B Special purpose part Special purpose part Standard part Subassembly B1 Standard part Special purpose part Generalized component decomposition a. type, number, arrangement of components b. standard or special purpose (make or buy)

  15. Product Architecture def – the scheme by which the • functional elements of a product are arranged • into physical building blocks (components, subsystems or subassemblies) • that interact with each other • to perform the overall function of the product. Product architectures can be “modular” or “integral”

  16. Modular architecture • Product examples • Flashlight • Refrigerator • Automobile • Personal computer Modular components Batteries, bulbs Motors, compressor, switches Tires, radios, seats, pumps engines Drives, keyboards, mice, modems • chunks implement one or a few functions, • interactions between chunks are well defined • (standard interfaces / connections)

  17. Integral Architecture Product examples BMW Motorcycle engine Printer case Shaft Beverage cup Integrating aspects engine/frame integral snap-fasteners machined bearing race integrated handle • a single chunk implements many functions • interaction is ill defined • physical element “shares” functions

  18. Steps for developing a product architecture • create a schematic of functional and physical elements • cluster elements into logical chunks to: • exploit standard components • to exploit standard interfaces (e.g. 120 VAC, RS232 ) • fully utilize manufacturing process(es), or vendors • provide for maintenance • sketch a rough geometric layout • identify interactions between elements • refine layout

  19. Printer Example

  20. Cluster elements into logical chunks

  21. Sketch rough geometric layout

  22. Sketch interaction diagram

  23. Best concept(s) Part configuration design Product architecture Integral / modular Standard / special purpose Configure Product Re-examine EDS Research sources Configuration requirements sketch Configure Part(s) Iterate Design for Function Design for Assembly Design for Manufacture Analyze and Refine Pugh’s Method Weighted Rating Method Evaluate Best configuration(s)

  24. Part configuration design geometric features include:

  25. Abstract embodiment different features alternative arrangements different relative dimensions How can we “generate” alternative part configurations? Recall bracket configurations

  26. Example: configuring a sponge holder Step 1. Prepare configuration requirements sketch sponge holder Step 2. Prepare non-contiguous config. requirements sketch

  27. Step 3. Prepare alternative contiguous configuration sketches

  28. Step 4. Refine configurations with hole in back wall with hole in offset wall

  29. Best concept(s) Configuration design - analysis Product architecture Integral / modular Standard / special purpose Configure Product Re-examine EDS Research sources Configuration requirements sketch Configure Part(s) Iterate Design for Function Design for Assembly Design for Manufacture Analyze and Refine Pugh’s Method Weighted Rating Method Evaluate Best configuration(s)

  30. To analyze configurations, we ask… Will it function? Will it assemble? Will it be manufacturable?

  31. 1.  Strong 2.  Stiff or flexible 3.  Buckle 4.  Thermal expansion 5.  Vibrate 6.  Quiet / Noise 7.  Heat transfer 8.  Fluids transport / storage 9.  Energy efficient 10. Stable 11. Reliable 12. Human factors/ergonomics 13. Safe 14. Easy to use 15. Maintain 16. Repairable 17. Durable (wear, corrosion) 18. Life-cycle costs 19. Styling/aesthetics Design for function Will the part or product perform its function(s)?

  32. Will it assemble? What do we mean by assemble? Assembly - a process of handling components to bring them together (inserting) and then fastening them.

  33. Reduce handling • 1. Handling - (GMOP: grasping, moving, orient, place). • design parts or products to reduce the influence on handling: • size, thickness, weight, • nesting, tangling, fragility, • flexibility, slipperiness, stickiness, • need for 2 hands, tools, optical magnification or mechanical assistance.

  34. Reduce inserting and fastening effort • 2. insertion & fastening - mating a part to another part or sub-assembly. • design parts and products to reduce the influence of: • accessability resistance (force) to insertion • visibility ease of alignment & positioning • depth of insertion separate operation required • fastener used

  35. DFA Design for Assembly - a set of design practices which reduce the manpower time required to handle, insert and fastencomponents of a product.

  36. Design for Assembly Guidelines from SME • minimize part count • minimize levels of assembly (number of assemblies) • encourage modular assembly • use standard parts • stack sub-assemblies from the bottom up • design parts with self-fastening features (snap-fits, press-fits) • facilitate parts handling (grasp, orient, move) • design parts with self-locating features (e.g. chamfers, aligning recesses/dimples) • eliminate reorientation (i.e. insertion from 2 or more directions) • eliminate (electric) cables

  37. DFA Graphical 1

  38. DFA Graphical 2

  39. DFA Graphical 3

  40. DFA Graphical 4

  41. Pros and cons of DFA methods • 1. Design Guidelines • pros: fast, easy, non-coupled • cons: non-quantitative, can’t compare alt. designs • 2. Assembly Efficiency (Boothroyd & Dewhurst) • Ema = theoretical min. assembly time • estimated assembly time • pros: systematic, comparative • cons: takes time to code & calculate

  42. DFM Deign for Manufacture (manufacturability) - A set of practices that aim to improve the fabrication of individual parts 1. Design Guidelines (written and graphical) 2. Cost estimating methods (difficult w/o dimensions)

  43. DFM – Injection molding / casting • avoid designing parts with thick walls or heavy sections • design parts without undercuts • choose material for minimum total part cost • (i.e. tooling, processing, material) • design external threads to lie on parting plane/surface • add ribs for stiffening

  44. DFM – Sheet metalworking • avoid designing parts with narrow cutouts or projections • minimize manufactured scrap (cut-off versus blanking) • reduce number of bend planes • keep side-action features to a minimum or avoid completely

  45. DFM - Machining • employ standard features (e.g. holes, slots, chamfers, fillets, rounds) • use raw material available in standard forms (e.g. sheet, roll, bar, plate) • avoid sharp internal corners on turned parts • specify liberal tolerances and surface finishes

  46. Obtaining the “best” configuration To choose the “best” alternative…. Implies that we have a number of feasible alternatives! To be selective, we need a selection! How should we start our configuration design efforts?

  47. Best concept(s) Product architecture Integral / modular Standard / special purpose Configure Product Re-examine EDS Research sources Configuration requirements sketch Configure Part(s) Iterate Design for Function Design for Assembly Design for Manufacture Analyze and Refine Pugh’s Method Weighted Rating Method Evaluate Best configuration(s) Configuration design - evaluation

  48. Let’s evaluate the Sponge holder configurations with hole in back wall with hole in offset wall

  49. Evaluation using Weighted Rating Method • List evaluation criteria (in a column). • Determine importance weights (in an adjacent column) • List alternatives (along the top row) • Rate each alternative on each criterion • Compute the weighted rating for each criterion • Sum the ratings to produce the Overall Weighted Rating

  50. Evaluating alternative configurations

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