Rating design requirements in fuzzy quality function deployment via a mathematical programming approach

Quality function deployment (QFD) is an important tool for translating customer requirements into product features. Identification of critical design requirements is a key factor for product development to satisfy customer needs. When the relative weights of customer attributes and the relationship measures between customer attributes and design requirements are fuzzy numbers, the determination of the design requirements becomes more complicated in QFD planning process. The calculation of the technical importance of design requirements falls into the category of fuzzy weighted average. Since the derived membership functions of the technical importance of design requirements are not explicitly known, the paper devises a method that can prioritize the design requirements without knowing their exact membership functions. The ratings of the design requirements are determined by solving a pair of nonlinear programs for each design requirement. The impacts of correlation among design requirements and the budget factor are also considered for achieving higher customer satisfaction. An example of a flexible manufacturing system design is given to illustrate the application of the proposed method.