ee3.pem Product & Engineering Management Creative design Process

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1 ee3.pem Product & Engineering Management 1 Creative design Process What is engineering design Object and artefacts Traditional crafting merges design & manufacture Modern design separates design & manufacture Design output is complete description of project Contrast with other kinds of design 2

2 mini 3 Design Generation Mysterious creative aspect Consider as exploration of designs in solution space Design requires different way of thinking Right and left side of brain Start with problem statement, maybe vague In 1961, Kennedy s goal to land someone on the moon within a decade Problem statement includes Goals Constraints Criteria for success 4

3 Design as ill-defined problem The kinds of problem that designers tackle are regarded as illdefined or ill-structured, in contrast to well-defined or well-structured problems such as chess-playing, crossword puzzles or standard calculations. Well-defined problems have a clear goal, often one correct answer, and rules or known ways of proceeding that will generate an answer. The characteristics of ill-defined problems can be summarised as follows. 5 No definitive formulation of the problem When the problem is initially set, the goals are usually vague, and many constraints and criteria are unknown Any problem formulation may embody inconsistencies The problem is unlikely to be internally consistent; many conflicts and inconsistencies have to be resolved in the solution Formulations of the problem are solution-dependent Ways of formulating the problem are dependent upon ways of solving it Proposing solutions is a means of understanding the problem Many assumptions about the problem, and specific areas of uncertainty can be exposed only by proposing solution concepts There is no definitive solution to the problem Different solutions can be equally valid responses to the initial problem 6

4 Learn to design Synthesis & Analysis Top-down and bottom-up Eg circuit design Search both problem and solution space Consider how successful designers do it 7 Models of design Two basic types intuitive and rational 8

5 French s model Result of the analysis of the problem is a statement having three elements: Statement of design problem - goals Limitations placed upon solution - constraints Criterion of excellence design criteria 9 Rational models Analysis: listing of all design requirements and the reduction of these to a complete set of logically related performance specifications. Synthesis: finding possible solutions for each individual performance specification and building up complete designs from these with least possible compromise. Evaluation: evaluating the accuracy with which alternative designs fulfil performance requirements for operation, manufacture and sales before the final design is selected. 10

6 Archer s model Programming: establish crucial issues; propose a course of action. Data collection: collect, classify and store data. Analysis: identify sub-problems; prepare performance (or design) specifications Synthesis: prepare outline design proposals Development: develop prototype design(s); prepare and execute validation studies. Communication: prepare manufacturing documentation. 11 Pahl & Beitz s Model Clarification of the task: collect information about the requirements to be embodied in the solution and also about the constraints. Conceptual design: establish function structures; search for suitable solution principles; combine into concept variants. Embodiment design: starting from the concept, the designer determines the layout and forms and develops a technical product or system in accordance with technical and economic considerations. Detail design: arrangement, form, dimensions and surface properties of all the individual parts finally laid down; materials speci-ied; technical and economic feasibility re-checked; all drawings and other production documents produced. 12

7 Pahl & Beitz s Model 13 March s Model 14

8 Design procedures Brainstorming Analogical thinking Enlarge search space Creative thinking Systematic Methods 15 Brainstorming No criticism allowed Quantity rather than quality of ideas Ideas briefly explained Ideas not checked for reasonableness Bootstrap ideas of others 16

9 Analogical thinking Direct analogies Biological analogies Symbolic analogies Fantasy analogies 17 Enlarge search space Transform problem Random input Ask why? Dialectic reasoning 18

10 Creative thinking recognition understanding incubation Creative ah-ha verification 19 Systematic Methods 1. Clarify objectives 2. Establish function 3. Performance specification 4. Quality function 5. Generate alternatives 6. Evaluate alternatives 7. Improving Details 20

11 1. Objectives tree: To clarify design objectives and sub-objectives, and the relationships between them 2. Function analysis: To establish the functions required, and the system boundary, of a new design. 3. Performance specification: To make an accurate specification of the performance required of a design solution. 4. Quality function deployment: To set targets to be achieved for the engineering characteristics of a product, such that they satisfy customer requirements. 5. Morphological chart: To generate complete range of alternative design solutions for a product, and hence to widen search for potential new solutions. 6. Weighted objectives: To compare utility values of alternative design proposals on basis of performance against differentially weighted objectives. 7. Value engineering: To increase or maintain the value of a product to its purchaser while reducing its cost to its producer. 21 Seven Stages of Design Process 22

12 Clarify objectives Objectives Tree Consider objectives & sub-objectives List design objectives Order list as hierarchy Draw tree of objectives Distinguish between functions and means 23 Example automatic tea-maker 24

13 Establish function Determine overall function as black box, inputs, outputs List sub-functions Draw block diagram showing interactions Define system boundary Find components for performing sub-functions 25 Example 26

14 Performance specification Consider product alternatives, types and features determine level of generality Identify performance attributes Specify performance requirements 27 Quality function Identify customer requirements for product attributes Rank or weight attributes Evaluate competitor s attributes Relate engineering characteristics & product attributes Draw quality function matrix Identify interactions between engineering characteristics Set targets for engineering characteristics 28

15 Example fan heater 29 Generate alternatives Morphological Chart List essential aspects, features and functions Identify sub-solutions for each aspect Draw morphological chart or matrix - all possible solutions Identify feasible combinations from matrix 30

16 Example - fork lift truck 31 Example - fork lift truck one solution 32

17 Evaluate alternatives Re-visit list of design objectives Rank & weight objectives e.g. pair-wise objective matrix Quantify or grade performance parameters Compare values of alternative designs 33 Example weighted objectives tree 34

18 Improving Details Value Engineering List separate components & identify function Determine values of components & functions Calculate costs Search for ways to Reduce cost without reducing value Adding value without adding cost Evaluate alternatives & select improvements 35 Technology push Market pull 36