Product Redesign Using Taguchi Method, Fuzzy Theory, and TRIZ

In industry, products often need to be redesigned, after they are on the market for some time, to adapt to new market trends. Compared with designing a new product from scratch, product redesign can reduce design cycle time and resources. The concept of product redesign is not extraordinary, but many prior studies only focus on particular products. A generic redesign method is needed. Additionally, product redesign often requires tackling problems related to improving the functions of a product. Introducing or adding new functions might cause some indistinct contradictions between the new and existing functions of the product. Often, such contradictions might not be found until the final design stage is reached. To find out contradictive information in short time and deal with the majority of products, we present a comprehensive redesign method using the Taguchi method, fuzzy theory, and TRIZ. The major assignments of this paper are described as follows.1) Find the contradictive components between the new functions and existing functions.2) Reduce the unnecessary design by selecting more important components.3) Eliminate the contradictions between the contradictive components by TRIZ. In the initial stage of the product design, products which need to be redesigned need to be decomposed into several components first. Then, designers can evaluate the importance of each component by fuzzy theory, based on the designers’ and consumers’ opinions. Thus, the more important components can be found for further analysis. With the proposed approach, the Taguchi method is used to find contradictions after obtaining the more important components. Taguchi control factors are replaced by product components. In the past, designers eliminated or decreased interactions by eliminating interactive parameters or changing the levels of interactive parameters. With the developed approach, component interactions are regarded as contradictive information. After finding interactive components, rather than removing the interactive components, TRIZ is used to eliminate the contradictions by keeping and improving the existing functions of the interactive components. After eliminating all contradictions, a conceptual design solution is created for the new product. Finally, a bike redesign example is introduced to illustrate and support the validity of the developed product redesign method.