Incorporating expedited time and cost of the end product into the product structure diagram

This paper presents an algorithm for determining expedited time and cost of the end product in the product structure diagram (PSD) using critical path method (CPM) and time-costing method. The classical PSD provides essential information for the consequent material requirement planning (MRP). Such information includes the parent-child relationship between the end item and its components at each level, the number of components required at the child level in order to produce one unit at the parent level, and the number of periods required for production of each component. Selecting an appropriate acquisition method (either manufacturing process or speed of assembly or specific supplier) for each component is one of the early tasks faced by a product/process design team and it is critical because that the resulting decisions are then translated into the PSD and its subsequent material requirement planning. In this study, we propose a step-by-step decision procedure using the CPM and time-costing method for determining the optimal component procuring alternatives when expediting end product's completion time is desired. A numerical example demonstrates its practical usage.