The Application Of Fuzzy Reasoning For Quality Function Deployment

Abstract

The objective of this paper is to apply a fuzzy reasoning approach for the Quality Function Deployment (QFD) of product design in order to achieve product quality assurance prior to manufacturing. This approach, first, applies fuzzy theory for the construction of central relationship matrix to represent the degree of relationship between customer quality requirements and engineering design characteristics of the product for the purpose of quality function deployment. The degree of relationship, expressed as a fuzzy value between 0 and 1, shows the extent that a certain engineering design characteristic satisfies the corresponding customer quality requirement and is acquired from the integrated knowledge of cross-functional expertise. On the other hand, a fuzzy input vector should be formed to represent the degree of membership for each observed customer quality requirement. The degree of membership, expressed as a fuzzy value between 0 and 1, shows the importance of each observed customer quality requirement and is acquired from practical marketing investigation and analysis of customer needs. Then, four steps of fuzzy relational products arc used to compute the fuzzy inferential value of each engineering design characteristic for the QFD practice. The larger tile fuzzy inferential value is, the more degree-of-belief and the more important is the particular engineering design characteristic. This approach will assist the QFD product designer in planning future focus of engineering design characteristics more objectively to achieve overall customer satisfaction. Finally, a demonstrated example regarding to the product design of a lighter will be given to simulate the proposed approach.