Abstract: A new tool path generation method based on Z-buffer method is proposed for composite surface machining by using torus cutters. Firstly, the examining area is determined by means of Z-buffer method. Then interference-free tool positions with optimal machining strip width are obtained by matching the end surface of the torus cutter to the model surface as close as possible. The discretized points within the examining area are efficiently read in and stored directly by the computer hardware; no extra searching and iterative methods are needed. Interference checking and avoiding methods are combined with the adjusting process of the cutter, so the tool positions generated are interference-free. Triangulated model is used in the newly developed method which is particularly suitable for tool path generation of composite surface. The new method is used to generate tool path for a mold surface and the result shows that, comparing to traditional machining method with ball end cutter, the new method raises efficiency by ten times. Finally, simulation and cutting test are performed.

Key words: Composite surface, Computer graphics, Depth buffer, Interference checking, Tool path generation method