An Axiomatic Approach to Managing the Information Content in QFD: Applications in Material Selection

Material selection takes on a strategic importance to meet the highest level standard of a product/process design. The evolution of legislative, regulatory and functional needs makes this selection extremely complex as it is the result of several compromises involving the consumer. Choosing the wrong material produces product failures, reliability problems and high costs. On the other hand, the many compromises needed during product design are often responsible for a non-optimal final design and for a reduction in the design process efficiency (delays in schedule or a rise in the cost). In the material selection process, the designer has to deal with a lot of trade-offs. These are often caused by a failure to identify the functional specifications that are related to the materials (i.e. limited weight, ability to conduct heat, wear resistance, etc.). In many cases, however, the designer has correctly understood the functional specifications but there is a deficiency in the mapping of the connections between the functional specification and the physical characteristics (i.e. density, thermal conductivity, hardness, etc.). A systematic strategy to drive the designer to discover and map the correlation between the different physical characteristics is also missing. This paper shows how, using the Information Axiom of Axiomatic Design Theory, the designer can clearly define the functional specifications as functional requirements (FRs) and identify the mutual correlation between the different physical characteristics (the design parameters used in Axiomatic Design). In this way, material selection during the development of new product can be made more effective and innovative.