A DECISION SUPPORT SYSTEM FOR MATERIAL AND MANUFACTURING PROCESS SELECTION. RONALD E. GIACHETTI. Manufacturing Systems Integration Division, National Institute of Standards and Technology, Bldg. 304 Rm. 4, Gaithersburg, MD, 20899, phone: (301)975-4560, email: giachett@cme.nist.gov

Designers are faced early on with the daunting task of selecting materials and manufacturing processes when the information content of the design is imprecise and inherent uncertainty exists. These preliminary engineering decisions are important since they have a great effect on the overall product costs. Insufficient evaluation of the alternatives can lead to suboptimal designs or impose unnecessary restrictions on the design. It is becoming increasingly clear that the tremendous number of materials precludes an iterative search for alternatives. Many of the existing systems rely on highly specialized knowledge and require a significant amount of time and cost that make these tools in general unavailable early in design. This paper describes the development of a prototype material and manufacturing process selection system that integrates a formal multi-attribute decision model with a relational database. The imprecision in preliminary design specifications is modeled using a set representational formalism. A relational algebra is developed to allow imprecise queries on the material and process database. The compatibility of a material and manufacturing process alternative is assessed using possibility theory. This integrated decision support system allows a more efficient search of the design space by identifying different material and process alternatives early in the design process when it is easier to make design changes. The alternatives are ranked enabling the designer to concentrate on those alternatives that have the greatest potential for balancing the product s functional requirements with the economic concerns realized in manufacturing.