1999_Kazmer_RiED Evaluation of Product and Process Design_preprint

1999_Kazmer_RiED Evaluation of Product and Process Design_preprint

Critical design decisions are commonly made throughout product development assuming known material and process behavior. However, the final manufactured product properties depend upon the specific tool geometry, material properties, and process dynamics encountered during production. Moreover, slight random variations during manufacture can inadvertently result in inferior or unacceptable product performance and reduced production yields. Stochastic simulations have been developed to estimate the end-use performance distribution prior to the commitment of hard tooling. This paper extends these methods to model the important role of the manufacturing response in process optimization and elimination of defects. Small changes in the manufacturing method can frequently improve the product quality and eliminate small flaws in the product design. Three contributions are made in the domain of net shape manufacturing. First, a definition for robustness is presented. In addition, in the appendix, this definition of robustness is proven to be convex, making it extremely suitable for optimization techniques. Second, a robust design methodology is introduced and contrasted with conventional development methods. Finally, this methodology is applied in the example of the concurrent design of a molded plastic part.