AN AUTOMATIC PATH GENERATION METHOD OF NC ROUGH CUT MACHINING FROM SOLID MODELS

This paper presents a Grid Height method for tool path generation of N C rough cut machining. Solid models that contain planar surfaces, gene ral quadratic surfaces, B-spline surfaces and compound surfaces can be treated. This rough cut scheme transforms a B-rep solid object into a grid model, allowing a 3D object to be approximated by a 2D array, th e spatial array. The cutter locations (CL) data file will be automatic ally generated from the spatial array. The height change of stock mate rial in each grid is also recorded in a 2D stock height array during t he machining process. The tool paths generated from the proposed metho d are proved to be gouge free by checking the height change of each gr id. In addition, the feasibility of this NC verification concept has b een tested by the implementation of a computer simulation for the tool path. Finally, two example parts, the CAM-I benchmark workpiece and a part constructed with the B-spline surface, are machined successfully to demonstrate the applicability of the developed method.