Engineering change analysis during ongoing product development

Engineering changes are part of any design process. Changes are often requested even before a product design has been completed. However, change requests during an ongoing design process are difficult to assess because the design is still evolving. Some parts, where only conceptual designs exist, may be easy to change; other parts may already be frozen and hence more difficult and probably more expensive to change. In order to find the best way to implement a change at a given time, the designer needs to be aware of not only the design and the interactions, but also of the state of development of every part. However, many designers are not always aware of all interactions and, hence, unexpected and expensive change alternatives are chosen. This paper focuses on the question of how designers can be made aware of the impact of a proposed change before they commit. It discusses the links between the product, process and people domains that interact during product development, listing limiting factors that make change implementation risky and lead to increased change cost. The paper presents a tool to evaluate change proposals during ongoing design processes where the state of the development of parts is taken into account. The tool extends the Cambridge Change Prediction Method which assesses the risk of changes propagating between two parts. The paper concludes with the findings of two tool evaluation studies.