A metric for evaluating design commonality in product families

Many companies develop a market strategy built around a family of products. These companies regularly add new product variations to the family in order to meet changing market needs or to attract a broader customer base. Although the core functionality remains essentially unchanged across the products within a family, new functions. feature combinations and technologies are incorporated into each new: product. If allowed to grow unchecked, these component variations, commonly: referred to as ''complexity", can result in a loss of productivity or quality. The challenge lies in an effective management of product variations in the design studio and on the manufacturing floor. The key is to minimize non-value added variations across models within a product family without limiting customer choices. In this paper we discuss the factors that contribute to product complexity in general, and present an objective measure, called the Product Line Commonality Index, to capture the level of component commonality in a product family. Through our Walkman case study, we present a simple yet powerful method of benchmarking product families. This method gauges the family's ability to share parts effectively (modularity) and to reduce the total number of parts (multi-functionality).