Formulating design problems

Transcription

1 Formulating design problems n n n n n n Design of a high-performance motorcycle What is a design problem? Why is the formulation phase important? Customer & company requirements Sources of information The overall process

2 Two basic design problems n n An opportunity to make and sell a new product Need to fix an existing product deficiency Determine customer & company requirements think Function.. not Form How do we solve?

3 Types of design (are they strategies? ) Formulation Add this to book! Concept Design Configuration Design original design Part conf. design Configuration Design variant design selection design Do nothing Parametric Design Parametric Design Parametric Design Detail Design Detail Design Detail Design Detail Design Best strategy depends on a knowing the details, i.e. a good formulation

4 How do we solve a design problem? Design problem (function, customer need) Formulate first Decision making processes and activities Solution (form, manufacturable product design)

5 Example: Improve an existing motorcycle design What info would help us understand the design problem? How quickly should the cycle accelerate to 60 mph? What should the top speed be? Is fuel consumption less important than acceleration? What riding comforts are expected? Is an electric starter desired? Will the customer tolerate a liquid cooling system? Will customer care about aesthetics?

6 During the design problem Formulation Phase Recall we re not solving yet we are Trying to understand, and plan. Therefore, we search for information about Customer Requirements Company Requirements

7 Formulating (a design problem) Formulating process Customer needs? Competition? Functional requirements? Targets? Constraints? Evaluation criteria? Preliminary design specifications Initial design problem description Seek info Interpret Summarize Gain consensus probe revise Literature, Surveys Market Studies Focus Groups Observation Studies Benchmark Studies Obtain management approval Review continue discontinue principal output Engineering Design Specification

8 Customer requirements Function / performance Functions / Importance Engineering characteristics (units, limits) Performance Targets Satisfactions Operating Environment Air temp., humidity, pressure Contaminants Shock, vibration Other Economic Geometry Maintenance Repair Retirement Reliability Robustness Safety Pollution Ease of use Human Factors Appearance Note the deliberate absence of form attributes

9 Motorcycle design: Customer requirements Function / performance: start engine quickly, support rider(s) comfortably, Operating road shock wet, cold, high altitude Other maintenance intervals fuel economy

10 Company Requirements Marketing Customer/Consumer Competition Strategy Time to market Pricing Advertising Sales demand, targets Manufacturing Financial Production quantity Product Processes, Materials Development New factory equip. Investment Warehousing & dist. Return on investment Other Regulations, Standards, Codes Patents / intellectual property

11 Motorcycle design: Company requirements Marketing: need product soon sale price competitive Manufacturing use existing manufacturing plant usual fabrication materials Financial Small R&D budget Typical ROI B/Taxes

12 From qualitative to. quantitative How will we know if our design will start quickly? How will we know if our design will go fast? How will we know if our design will steer easily? Therefore we need some quantitative measures! (unquestionable, factual, measureable, provable.)

13 Engineering characteristics, units, and limits Sub-function Engineering Characteristic Units Limits start engine quickly cranking time seconds 6 secs support rider(s) comfortably transport rider(s) fast steer bike easy Quantities cushion compression that measure inches the performance of a candidate design acceleration top speed 0-60 mph steering torque turning radius feet/ sec 2 mph/kph seconds (with respect to specific customer required functions). pound-ft feet 32 ft/s 2 90 mph 6 secs Absorb road shocks suspension travel inches > 5 in

14 Motorcycle Importance of each requirement Customer importance weights by sub-function Sub-function Weight start engine quickly 15 % support rider(s) comfortably 10 % transport rider(s) fast 50 % steer bike easy 20 % absorb road shocks 5 % total 100 %

15 Satisfaction values based on the amount of customer satisfaction Amount of satisfaction Value Most satisfied 1.0 Very satisfied 0.9 Moderately satisfied 0.8 Somewhat satisfied 0.6 Hardly satisfied 0.3 Not satisfied 0.0 qualitative quantitative

16 Satisfaction as a function of Top Speed (mph). Satisfaction arbitrary shapes Top Speed (mph) 150 Example of more is better

17 Satisfaction versus Cushion Compression (in.) Satisfaction Cushion Compression (inches) Example of target is better

18 Satisfaction versus Cranking Time (seconds) Satisfaction Cranking Time (seconds) Example of less is better

19 Information sources Surveys Market Studies Literature Focus Groups Observation Studies Benchmark Studies

20 Formulating (a design problem) Formulating process Customer & Company needs? Competition? Functional requirements? Targets? Constraints? Evaluation criteria? Preliminary design specifications Initial design problem description Seek info Interpret Summarize Gain consensus probe revise Literature, Surveys Market Studies Focus Groups Observation Studies Benchmark Studies Obtain management approval Review continue discontinue Engineering Design Specification

21 Planning steps? 1. obtain a detailed understanding of the design problem, 2. document our understanding in an EDS 3. choose a solution strategy 4. develop a project plan (scope of work, budget and schedule) 5. establish a consensus among team members & management

22 The secret for a successful solution is a. sound problem formulation