In order to increase the modeling power and productivity of CAD/CAM systems, there have been increased demands for CAD/CAM system customization. Customization of a CAM system involves 1) making it easier to learn and use, 2) adding new modeling features which are not supported in a general purpose CAM system, and 3) providing parametric inputting mechanisms. Thus, a general purpose CAM system is required to have customization supporting mechanisms so that it can easily be customized by the general users. In other words, the CAM system must provide certain "user interface mechanisms" on top of its "general CAM modules".
Proposed in this thesis is a customization supporting structure of a general purpose CAM system. In the propose scheme, the user develops his or her "custom module" using a general purpose programming language together with the "user interface functions" and then connects it to the target CAM system through the user interface mechanisms. The functional requirements of the CAM system structure supporting the user's programming were obtained based on the case developments of dedicated CAM systems for speaker modeling die machining, glass pattern cutting, and shadow mask forming die machining. These case studies revealed that a general purpose CAM system should have mechanisms for 1) involving the custom module to the custom module, 2) passing the user input from the CAM system module to the custom module, 3) calling required library functions from the custom module, 4) preparing and executing part programs from the custom module, 5) displaying geometric entities and handling files in the custom module. The case implementation has been carried out with the commercial CAM system OMEGA on a pentium PC.
