Development of a Decision Support System for Making Mold Specifications

Abstract

This paper deals with the development of computer-aided design systems for mold designers. Specifically a model of design process for working out mold specifications and the program structure of a decision support system developed on the basis of such a model are considered. These are the nuclei of AI-CAD and design expert systems for mold designing. Major features of the design process model and the program architecture discussed in this paper may be summarized as follows : (1) The design process is presented in a new form different from such a fixed designing process as described in the existing CAD systems for molds. (2) All items in mold specifications which are called “design variables” in the design process are given as a set of attributes or functions. (3) The process for deciding on the solutions of design variables forms a hierarchical model consisting of three phases represented in the so-called “design knowledge”, including design strategy, a graphic representation of correlations, the values of attributes or functions, and design equations. (4) The knowledge base that forms an integral part of this system can be developed by directly rewriting the design knowledge formulated in the hierarchical model in accordance with the production rule. (5) Knowledge engineering and an optimization method are used in deciding on the values of those variables which are called “design solutions” in the design process. Choosing specifications of injection molds for a design task, this paper also discusses the development of knowledge and optimization processing modules for the decision support system for working out such mold specifications, and then proves the validity of these processing modules through case studies.