Optimal timing of reviews in concurrent design for manufacturability

Concurrent design can reduce the time required to develop new products and redesign old ones. In contrast to the conventional approach, in which the product design is (nearly) completed before it is ‘thrown over the wall’ to the process design group, concurrent design for manufacturability, as conceptualized here, conducts a number of progress reviews during the product design process. Frequent reviews have two benefits: (1) (Parallel Development) process designers receive sufficient information about the design to enable them to work in parallel with the product designers, and (2) (Quality Control) flaws in the design are discovered soon after they are introduced, saving the time and resources required for redesign later. The disadvatnage of frequent reviews is that each review requires setup/penalty time that overwise would not be required. The optimal policy is derived for some special stationary cases of the model. When the parallel development benefit dominates, the review periods either increase or decrease according to the rate at which product design work empowers useful process design work to be conducted. When the quality control benefit dominates, the review periods will vary only to the extent that the quality related parameters change. Numerical examples illustrate the insights gained from the analysis.