2 nd Nordic Conference on Product Lifecycle Management – NordPLM’09, Göteborg, January 28-29 2009 ESTIMATING THE PROCESS COST OF IMPLEMENTING ENGINEERING CHANGE ALTERNATIVES Naveed Ahmad, David C. Wynn and P. John Clarkson Abstract Requirement changes can arise at many points throughout the product life-cycle. Meeting these changed needs necessitates engineering changes to the design. There are various methods and tools to understand such engineering changes in terms of the knock-on effects which could propagate through the system and require change to many other elements of the design. However, there is currently little support to help designers and managers evaluate proposed changes in terms of the total process cost of implementing them and executing any knock-on rework which may occur. Such support would be useful since there are often multiple ways to implement a requirement change, and it is thus important to identify the most cost-effective option prior to beginning its implementation. This paper proposes the basis of a model-based approach to provide such support. The approach is illustrated by discussing its application to the example of bicycle design. Further work to enhance and implement the approach is outlined. Keywords: Engineering Change Implementation Process, Change Prediction Method, Applied Signposting Model (ASM) 1 Introduction Designers can often identify alternative ways to implement a change request. However, evaluating which of the multiple options would be most cost-effective to implement – or whether the change is feasible at all – can be difficult. This arises in large part since change implementation cost is influenced by the product, the redesign process and other processes which are executed concurrently in the organisation: 1. The product. Engineering change initiated in one element of the design tends to propagate between other, related elements [1]. The total cost of implementing a given change therefore includes the cost of redesigning not only the initiating aspects of the design, but also all other aspects which will ultimately require modification due to change propagation. 2. The redesign process. Each aspect of the design which requires change must be modified by undertaking one or more redesign tasks. This might involve rework of tasks which were completed earlier in the design process as well as the execution of ‘new’ redesign tasks. Since processes can be viewed as networks of interconnected tasks which derive output information from input information, knock-on rework could also be required to many tasks downstream of those originally executed to redesign the affected elements of the product. Total implementation cost thus includes the cost of executing not only those redesign tasks initiated directly, but also those requiring indirect rework. Cost is also influenced by the amount of rework required for each task, which may be different from the amount of work required on the first attempt. 1