(Dr. Janet Allen, advisor)

"Coupled Design Decisions in Distributed Design"

Abstract

With the current push towards reducing the time required for the completion of the product realization process, rapid prototyping is becoming a tool which designers use regularly. One method of using rapid prototyping technologies in product development is to produce rapid prototypes of a final part. Another application is the rapid production of manufacturing tools, such as injection molds. The fabrication of these tools is commonly referred to as rapid tooling. These tools are then used to produce the final desired parts. When producing these prototypes, parts, and tools, designers and manufacturers are faced with multiple decisions to be made. Of particular interest here is the selection of the most feasible process and material combination for the development of the prototype, tool, and final part, and the determination of their most feasible dimensions. This tool and part design process involves the collaboration of a designer and manufacturer in a design environment which is often forced to be distributed. In addition, designers and manufacturers are often uncertain about exact specifications for materials and processes, as well as those for the tools and final parts. In this thesis, attention-directing tools are presented which allow designers and manufacturers in a distributed design environment to collaborate in the simultaneous, or coupled, selection of rapid prototyping materials and processes and the determination of feasible dimensions for a part prototype, rapid tool, and final part under uncertainty. The examples presented involve a simple rib which must be prototyped using rapid prototyping materials and processes and produced using a rapidly prototyped injection mold. The prototyped part must be able to withstand the loading and application specifications specified for the final part. This allows for testing of the prototype under conditions similar to those of the final part. In addition, the prototype dimensions must model those of the final part as closely as possible. If a mold has been rapidly prototyped, the mold must be able to withstand the forces, stresses and strains imposed on it in the injection molding process. Through the use of several examples involving the coupled decisions necessary for the design of the part and mold, a method by which a designer may intelligently perform coupled decisions for engineering problems in real-world situations is presented.