An index-based method to manage the tradeoff between diversity and commonality during product family design

The competitiveness in today's market forces many companies to rethink the way they design products. Instead of developing one product at a time, many manufacturing companies are developing families of products to provide enough variety for the marketplace while keeping costs relatively low. Although the benefits of commonality are widely known, many companies are still not taking full advantage of it when developing new products or redesigning existing ones. One reason is the lack of appropriate methods and useful indices to assess a product family based on commonality and diversity. Although many component-based commonality indices have been proposed in the literature, they emphasize commonality at the expense of diversity in a product family. In this study, the design for commonality and diversity method based on two new commonality indices - the commonality diversity index and the comprehensive metric for commonality - is introduced to help designers manage the inherent tradeoff between commonality and diversity during the product family design process. To illustrate the proposed method, an example application involving a family of single-use cameras is presented. The proposed method provides useful recommendations at both the functional and component levels during product family design.