REQUIREMENTS AND ARCHITECTURE OF A CAM-ORIENTED CAD SYSTEM FOR DESIGN AND MANUFACTURE OF MECHANICAL PARTS.

摘要

This work focuses on the Computer Aided Design and Computer Aided Manufacturing (CAD/CAM) of mechanical parts and on the advantage of an approach to solid definition based on a three-dimensional geometric model that considers manufacturing processes during the design phase. We refer to this as CAM-oriented CAD methodology. Much effort is being spent on establishing the cliched "bridge between CAM and CAD". In pursuit of integrated CAD/CAM systems, we believe that our CAM-oriented approach to CAD promises significant benefits in the design-to-manufacture cycle of production.; Geometric solid modeling is a fundamental requirement for CAD/CAM systems that deal with mechanical parts. Several such modeling schemes have been proposed and are used in existing systems. This work includes an extended introduction to several commercially available and experimental systems, and reviews popular solid representation schemes, discussing their potentials as candidate models for integrated CAD/CAM systems. A new mathematical formalism for modeling of solid, rigid bodies, called Realizable Shape Calculus (RSC), is developed. This new model is similar in spirit to Constructive Solid Geometry (CSG), except that it is also capable of consistently modeling assemblies of real-world objects, and covers a wider class of realizable shapes.; Descriptive solid modeling schemes such as CSG or RSC, are not suitable user-level part definition models for integrated CAD/CAM systems. Following our CAM-oriented methodology, it is shown how an operational approach to mechanical part definition can serve as a foundation for a manufacturing-oriented integrated design language. Such a language must provide operations meaningful to both designer and manufacturer, resulting in part definitions expressed in terms of components with meaningful counterparts in production cycles. Reflecting this view of mechanical part design, a skeleton design language called DSG, based on RSC and suitable for a truly integrated CAD/CAM system, is proposed and its major features are discussed.