Machine and product design_3_elearning.pdf
- 1. Machine and product design Dr. Czégé Levente DEBRECENI EGYETEM MŰSZAKI KAR GÉPÉSZMÉRNÖKI TANSZÉK
- 2. Intuitive and discursive problem solving Machine and product design 3. 2 • What is the difference?
- 3. Intuitive and discursive problem solving • Intuitive thinking is strongly associated with flashes of inspiration. The actual thinking process takes place to a large extent unconsciously. • The solutions suddenly appear as conscious thoughts and often their origins cannot be traced. • “The good idea is not discovered or undiscovered; it comes, it happens”. It is then developed, modified and amended, until such time as it leads to the solution of the problem. • Good ideas are always scrutinised by the subconscious or preconscious in the light of expert knowledge, experience and the task in hand, and often the simple impetus resulting from the association of ideas suffices to force them into consciousness. That impetus can also come from apparently unconnected external events or discussions. Machine and product design 3. 3
- 4. Az intuitív és diszkurzív problémamegoldás • There is the popular myth that creative ideas arrive with flash-like spontaneity—the flash of lightning and clap of thunder routine. • However, researchers of the creative process assure us that most ideas occur by a slow, deliberate process that can be cultivated and enhanced with study and practice. Machine and product design 3. 4
- 5. Intuitive and discursive problem solving • Generally time is needed for undisturbed and unconscious “thinking” before sudden insights appear. The length of this incubation period cannot be predetermined. • the right idea rarely comes at the right moment, since it cannot be elicited and elaborated at will • the result depends strongly on individual talent and experience • there is a danger that solutions will be circumscribed by preconceived ideas based on one’s special training and experience. Machine and product design 3. 5
- 6. Intuitive and discursive problem solving • Discursive thinking is a conscious process that can be communicated and influenced. The steps are chosen intentionally. • Facts and relationships are consciously analysed, varied, combined in new ways, checked, rejected, and considered further. • This type of thinking involves checking exact and scientific knowledge and building this into a knowledge structure. • In contrast to intuitive thinking, this process is slow and involves many small conscious steps. • A problem is rarely tackled as a whole, but is first divided into manageable parts and then analysed. • It must, however, be stressed that intuitive and discursive methods are not opposites. Experience has shown that intuition is stimulated by discursive thought. Thus, while complex assignments must always be tackled one step at a time, the subsidiary problems involved may, and often should, be solved in intuitive ways. Machine and product design 3. 6
- 7. Intuitive and discursive problem solving • There is no guarantee, that the discursive design methods based on intentional variation and combination of elements of solutions will result in better solutions than the intuitive way. • It is for sure, the increased number of solution elements increases the safety of the final solution of the discursive design technik. Machine and product design 3. 7
- 8. The problem solving method • The general problem solving cycle Machine and product design 3. 8
- 9. The problem solving method • The general problem solving cycle Machine and product design 3. 9 Problem analysis Problem clarification System synthesis System analysis Evaluation Decision Problem Next phase
- 10. The problem solving method • The general problem solving cycle Machine and product design 3. 10
- 11. A problémamegoldás általános módszere Machine and product design 3. 11
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- 13. Machine and product design 3. 13
- 14. The design process 1. Planning and Task Clarification The purpose is to collect information about the requirements that have to be fulfilled by the product, and also about the existing constraints and their importance. Result: the specification of information in the form of a requirements list 2. Conceptual Design It determines the principle solution. This is achieved by abstracting the essential problems, establishing function structures, searching for suitable working principles and then combining those principles into a working structure. Result: specification of a principle solution (concept). 3. Embodiment Design It determines the construction structure (overall layout) of a technical system in line with technical and economic criteria. Result: specification of a layout. 4. Detail Design The arrangement, forms, dimensions and surface properties of all of the individual parts are finally laid down, the materials specified, production possibilities assessed, costs estimated, and all the drawings and other production documents produced. Result: specification of information in the form of production documentation. Machine and product design 3. 14
- 15. A tervezés folyamata Machine and product design 3. 15
- 16. The design process Additional notes: • Most of the steps are performed in any case—albeit unconsciously— although they are often carried out too quickly, leading to unforeseen consequences. • This deliberate step-by-step procedure, on the other hand, ensures that nothing essential has been overlooked or ignored, and is therefore indispensable in the case of original designs. • In the case of adaptive designs, it is possible to reserve the procedure described for where it offers special benefits; • Experience has shown that only a little extra time is needed for a stepwise, systematic procedure. Machine and product design 3. 16
- 17. The design process Additional notes: • The overall length of the design based on systematical approach is less then that of the conventinal way. Machine and product design 3. 17
- 18. The design process • It is much cheaper and more effective to design the quality into the product, than later check it. Taguchi's methods help design engineers build quality into products and processes. • "Today the ultimate goal of quality improvement is to design quality into every product and process and to follow up at every stage from design to final manufacture and sale.” • Taguchi: a product or service has good quality if it "performs its intended functions without variability, and causes little loss through harmful side effects, including the cost of using it." • Function variability loss: e.g. energy and time (problem fixing), and money (replacement cost of parts). Harmful side effects could be market shares for the manufacturer and/or the physical effects for the consumer. Machine and product design 3. 18
- 19. The design process Three important premises: • for every product quality characteristic there is a target value which results in the smallest loss; • deviations from target value always results in increased loss to society; • loss should be measured in monetary units (dollars, pesos, francs, etc.). Machine and product design 3. 19
- 20. The design process • A crucial component of quality is a product's ability to perform its tasks under a variety of conditions. • The operating environmental conditions are usually beyond the control of the product designers, therefore robust designs are essential. • Robust designs are based on finding product parameter settings (e.g., temperature settings or drill speeds), which enable products to be resilient to changes and variations in working environments. Machine and product design 3. 20
- 21. Types of design tasks • original designs: realized by incorporate new solution principles. These can be realized either by selecting and combining known principles and technology, or by inventing completely new technology. • adaptive design: realized by incorporate known and established solution principles and adapts the embodiment to changed requirements. The emphasis is on geometrical (strength, stiffness, etc.), production and material issues. • variant design: , the sizes and arrangements of parts and assemblies are varied within the limits set by previously designed product structures (e.g. size ranges and modular products, see Chapter 9). It includes designs in which only the dimensions of individual parts are changed to meet a specific task. (principle design or design with fixed principle). • In practice it is often not possible to define precisely the boundaries between the three types of design. Machine and product design 3. 21
- 22. Types of design tasks Machine and product design 3. 22
- 23. Types of design tasks Machine and product design 3. 23
- 24. Tervezési feladatok fajtái Machine and product design 3. 24
- 25. Conditions of the design process • Batch size: one-off and small batch products, large batch or mass production. • Branch: the requirements and the type of solutions are diverse. For example, • food processing machines have to fulfil specific requirements regarding hygiene; • machine tools: specific requirements regarding precision and operating speed; • prime movers: power-to-weight ratio and efficiency; • agricultural machines: functionality and robustness; • Origin of the task: product planning group after thorough analysis of the market, customer order for a specific one-off or small batch product, etc. • Novelty • External conditions: market (frequent, fast developement), cost limits, deadline, special requirements (eg.:existing parts, technology), legal requirements, suppliers, etc.. Machine and product design 3. 25