Numerical control tool-path generation for subdivision surface using toroidal cutter on 5-axis machine tool

Subdivision surface, as a presentation of free-form surface with the stereo lithography (STL) format, has gained wide application in manufacturing industry recently, because of its simple geometric computation, robustness superior to parametric surface, and high efficiency in tool path generation. However, conventional tool-path generation methods can not be applied directly for STL model, and for 5-axis machine tools it is an even harder job considering yawing angle and tilting angle. Especially for toroidal cutters which machining work piece using the rounded edge, tool contact situation is even more complicated. In this paper an interference-free 5-axis tool-path generation algorithm using toroidal cutter is proposed to reduce tool ware and extend tool life span. A contacting model in cutting process is designed firstly, and profile similarity between ball-end cutter and toroidal cutter is analyzed, which is used to determine tool position. After planning tool-path, a novel step adjusting method is described to make it smoother and reduce cutter fluctuation, providing a substantial protection on machine tool and machining precision. At last, various illustrative complex surface examples are conducted to clarify its efficiency and robust by simulation on a PC with 2.0 G memory and 2.7 GHZ CPU.