Optimal Review Frequency in Concurrent Engineering

Concurrent engineering can reduce the time required to develop new products. In contrast to the conventional approach, in which the product design is (nearly) completed before it is “thrown over the wall” to process design group, concurrent engineering, as conceptualized here, conducts a number of progress reviews during the 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 disadvantage of frequent reviews is that each review requires setup/preparation time that would otherwise not be required. The form of the optimal policy is derived when the number of reviews is fixed and the review periods are continuous variables. In one case, the optimal review periods are equal and are given by an EOQ-like formula. In another, the review periods form a geometric sequence. In others, a hybrid, with a geometric phase and constant phase, is optimal. Explicit solutions for the optimal review policy are obtained when a first order approximation of the objective function is used. A numerical example illustrates the results.