Concurrent design of machined products: a multivariate decisionapproach

摘要

In the traditional process of product design, a sequentialnapproach treats each of the design steps individually withoutnconsidering requirements of manufacturing, assembly and other downstreamnactivities in the product life cycle. The lack of systematic andnsimultaneous consideration on the impact of design decisions onnmanufacturing and assembly leads to repeated and excessive changes inndesign and processes. To resolve this problem, the concurrentnengineering approach to product design foresees and avoids potentialndesign flaws by incorporating design requirements from downstreamnactivities of the product development life cycle early in the designnstage. This research develops a methodological framework for productnlife cycle design in concurrent engineering. Through a cohesivenorganization of semantics of high-level design features andnrelationships, this representation provides a means to evaluate thenimpact of design on subsequent activities in the product life cycle,nincluding design for manufacture (DFM), design for assembly (DFA), andndesign for productivity (DFP). In the first stage of a two-level design,nselection of design candidates is made based on multiple design criterianusing utility theory taking into account imprecision of designninformation and user preference. The second stage of design furthernfine-tunes attribute values of the selected design by a geneticnalgorithm based parametric optimization procedure. An illustrativenexample of two alternative designs of a milling fixture demonstrates theneffectiveness of the framework and its implementation methodology