GENERAL GEOMETRIC MODELING APPROACH FOR MACHINING PROCESS SIMULATION

Machining process simulation systems can be used to verify NC (numeric ally controlled) programs as well as to optimise the machining phase o f the production. These systems contribute towards improving the relia bility and efficiency of the process as well as the quality of the fin al product. Such systems are particularly needed by industries dealing with complex cutting operations, where the generation of NC code repr esents a very complex and error-prone task. A major impediment to impl ementing these systems is the lack of a general and accurate geometric method for extracting the required geometric information. In this pap er, a novel approach to performing this task is presented. It uses a g eneral and accurate representation of the part shape, removed material , and cutting edges, and can be used for any machining process. Solid models are used to represent the part and removed material volume. Bez ier curves (in 30 space) are used to represent cutting edges. II is sh own that by intersecting the removed material volume with the Bezier c urves, in-cut segments of the tool cutting edges can be extracted. Usi ng these segments, instantaneous cutting forces as well as any other p rocess parameters can be evaluated. It is also shown that by using B-r ep (Boundary representation) polyhedral models for rep resenting solid s, and cubic Bezier curves for representing cutting edges, efficient, generic procedures for geometric simulation can be implemented. The pr ocedure is demonstrated and verified experimentally for the case of ba ll end-milling. A very good agreement was found between simulated cutt ing forces and their experimental counterparts. This proves the validi ty of the new approach.