An object-oriented data model for managing computer-aided design and computer-aided manufacturing data bases

As a result of strong and steady CAD/CAM (Computer-Aided Design/Computer-Aided Manufacturing) growth over the past 20 years, special facilities for managing design and manufacturing data have been required. CAD/CAM Data Base Management Systems (DBMS) fill this role. The most widely used CAD/CAM DBMS manage data for only a single CAD or CAM application and cannot integrate graphical, geometrical, manufacturing, and administrative data. Furthermore, current modeling facilities are inadequate for representing semantic features and constraints captured by an engineering drawing. These limitations cause data flow gaps, inconsistent and redundant data, and unnatural data organization in existing CAD/CAM data bases. The purpose of this dissertation is to develop sophisticated facilities for managing CAD/CAM data bases. This work focuses on mechanical design, engineering, and manufacturing, specifically product definition data generated during initial design phases. Based on a detailed analysis of CAD/CAM data management requirements, and interaction with data management and manufacturing personnel at Lockheed Corporation and Rockwell International, I propose the following goals for integrated CAD/CAM DBMS: (1) conceptual centralization; (2) part-oriented BOM hierarchies; (3) customized representation of assemblies and parts; (4) incorporation of domain knowledge. The product of this research is the theoretical design of an object-oriented data model, ODM, and the implementation of an ODM computer software prototype supporting CAD/CAM DBMS goals. The ODM software system is written in T, a lexically scoped dialect of Lisp, and currently runs on Vax and Apollo networks in UCLA's Computer Science Department. The ODM system provides the following unique features: (1) object-oriented semantic modeling facilities; (2) dynamic schema capabilities; (3) semantic constraint maintenance; (4) heterogeneous data types. I conclude with an evaluation of ODM toward achieving the goals of integrated CAD/CAM DBMS. Data bases supporting Hughes' PWA (Printed Wiring Assembly) and Producibility Feedback applications were obtained for evaluation testing. Although most discussion concentrates on mechanical manufacturing; the developed methodology and tools for CAD/CAM data management also apply to other design and manufacturing domains such as architecture and electronics.