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.@en

Reliable change propagation is the key for successful change management. However, only a small number of support tools exist for the analysis of change propagation information. As change propagation data has many different facets, a set of different visualisation techniques is needed to assist designers in predicting change in complex products. In this paper we introduce different views on change propagation data. We show how this can be visualised using the CPM (Change Prediction Method) tool, a software tool currently under development for predicting change propagation. On the basis of an example case study at a UK diesel engine manufacturer, we show how different graphs can benefit design change management and which graphs are suitable for displaying which aspects of change propagation data.@en

A thorough understanding of change propagation is fundamental to effective change management during product redesign. A new model of change propagation, as a result of the interaction of form and function is presented and used to develop an analysis method that determines how change is likely to propagate. The analysis produces a Design Structure Matrix, which clearly illustrates change propagation paths and highlights connections that could otherwise be ignored. This provides the user with an in-depth knowledge of product connectivity, which has the potential to support the design process and reduce the product's susceptibility to future change.

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The relationship between a product and its design process is generally complex and not fully understood. When modifying a product, industry still rarely considers the implementation process and its consequences for other design activities in the company, which is hard to assess with conventional planning methods. Although change processes are highly constrained, product and process constraints are not usually considered together or traded off against each other when planning the change. Inadequate assessment and planning of the change implementation process can lead to costly knock-on effects across the product and the design process. This paper argues for a combination of change and process research and discusses requirements for a change process planning tool. It proposes a system for the analysis of the impact of change on the product as well as other company activities. Then, a more informed selection between change alternatives is possible.@en