Focused Product Family Improvement

Manufacturers in various industries are seeking to redesign their existing product families to better satisfy their diverse customer needs while maintaining competitive cost structures. Failure to carefully balance the commonality/variety tradeoff during product family redesign will catastrophically hamper the widely sought benefits of both appropriate commonality and variety. Existing product family redesign approaches often focus on increasing the degree of commonality or variety unilaterally and to their utmost, without considering the appropriate commonality/variety tradeoff based on both marketing and engineering resource concerns. The result is redesigned product families that are unachievable or much delayed. In this paper, the Focused Product Family Improvement Method (FPFIM) is proposed to help manufacturers utilize their limited engineering efforts to efficiently respond to market needs using their own competitive focus and commonality/variety tradeoff analysis. This method uses a graphical evaluation tool, the Product Family Evaluation Graph, to determine the necessary direction of improvement for product family redesign — either increasing appropriate commonality or increasing appropriate variety. A set of indices, the Commonality Diversity Index for commonality and variety, support the FPFIM in identifying components with undesirable commonality or undesirable variety, prime targets of redesign to satisfy the redesign intent. To illustrate the proposed method, an example application with four single-use camera families is presented.