An improved grey quality function deployment approach using the grey TRIZ technique

• We develop an improved grey QFD method by integrating interval grey numbers, QFD and TRIZ techniques.
• The proposed TRIZ method can effectively resolve contradiction problems between conflicting EC pairs.
• The input values and output results of the proposed method are interval grey numbers.
• A new grey ranking method is designed to precisely rate interval grey numbers.

Quality function deployment (QFD) can simultaneously consider both product functions and consumer needs during the product design and manufacturing stages. Traditional QFD often relies on market research or customer questionnaires to collect customer opinions in order to establish customer requirements. However, market research results (or those of customer questionnaires) usually contain a good deal of uncertain and incomplete information. Moreover, there is a practical problem in implementing QFD as experts in specific fields are often rare and difficult to find. In order to resolve these issues, this study integrated interval grey numbers, QFD and TRIZ techniques to develop an improved grey quality function deployment (GQFD) method. GQFD can assist product developers in identifying important engineering characteristics and can provide suggestions for possible improvements in engineering characteristics. Furthermore, this study developed a new grey ranking method to determine the ranking order of interval grey numbers. Finally, a real-world case study in Taiwan was used to explain the research process of the GQFD method and validate the practicality of the proposed method.