Synthesis of design concepts from a design for assembly perspective

Abstract

Assembly is often a labor intensive and costly process. Techniques such as design for assembly, and automatic assembly planning have been reported in an attempt to lower the high cost of assembly. Automatic assembly planning is concerned with finding the optimal sequence of assembly for a given design. On the other hand, design for assembly (DFA) examines the given design to evaluate its `fitness' for assembly, and where appropriate, to provide high-level suggestions to redesign the components so that they are easy to be assembled. Usually, DFA analysis is performed only when the design details are known (the number, types, and shapes of components and their mating relationships). As a result, designers tend to view this as an extra step/burden. To change this perspective, we investigate a new approach whereby DFA analysis is used to guide the designer in the search for a `good' initial design. In this paper, we propose an architecture that incorporates design for assembly analysis into the conceptual design phase. With this incorporation, timely suggestions are made available to guide the designer in his/her search for a feasible assembly-oriented design. A system has been developed (in the National University of Singapore) to realize this architecture. The system is written in C using the Pro/Engineer platform. the system takes, as input, a description of the product's functional requirements in the form of a state transition diagram. A library of past design cases in the domain of chairs has been created. A simple example of chair redesign has been presented to demonstrate the feasibility of the proposed scheme.