by
Edwin B. Dean
We frequently use the word 'design', but what is design? Akiyama (1991) notes that
- Design is an activity that recognizes the goals or purposes of products or systems.
- Design is an activity that shapes its objects - creates their forms - in accordance with the goals or purposes of those objects.
- Design is an activity that evaluates and determines the forms of its objects and makes their contents universally comprehensible.
- The product design process transforms abstract customer demands into specific product drawings.
- The product design process is a process of function allocation that identifies product purposes - such as functions - and allocates them to a structural product.
- The product design process manipulates information creatively.
- The product design process is a decision-making process.
Dean and Unal (1992) maintain that designing is defining and that function analysis and quality function deployment are premiere tools for defining. Jacobson, Christerson, Jonsson, and Overgaard (1992) portray design as an evolution from a low dimensional abstract model to higher dimensional concrete models.
There seem to be two extremes to the design process. Stauffer and Slaughterbeck-Hyde (1989) portray the the use of constraints to narrow the design space to the final solution. This seems to be the design satisficing process typically used in the U.S.A. Taguchi (1986) portrays the target based design optimization process developed in Japan to design quality into the product. Most design processes seem to use both the contraint and target concepts to some degree, although, they may be biased heavily to one extreme or the other. What is the best mix for the future? Time will tell. Multidisciplinary optimization is a test bed for that determination.
When we design, we design a system to satisfy a set of purposes. The typical system contains hardware, software, people, processes, purpose, organization, and behavior. When life is involved in the system to be designed, there are specific subsystems which must be considered (Miller, 1978). The associated considerations, such as safety, become a part of the set of purposes. The set of the purposes of the system is often called the requirements. The net effect is that we must design the system holistically and we must design the system for many purposes.
Given the above thoughts and almost 40 years of designing, I submit that, in the general sense, design is the definition of form to satisfy desire. That is why I also suggest that comprehensive QFD, implemented under total quality control, is the current process which most exemplifies the basic function of design.
All students of and teachers of engineering design should have read Jones (1981), Hollins and Pugh (1990), Pugh (1991) and Pugh (1996). Bralla (1996) addresses a number of things we now understand we must design for. Norman (1988) provides a refreshing perspective on user centered design.
My latest thoughts on design are here.