Toolpath Pattern Comparison: Contour-Parallel with Direction-Parallel

During rough cut machining of sculptured parts, appropriate selection of a tool path pattern in each cutting plane can significantly improve productivity. In this paper, various feasible toolpath patterns are investigated. A feedrate machining time model that takes into account CNC machine acceleration and deceleration for automatically identifying the most productive toolpath pattern is developed. This model is then used to compare the total machining time for common five types of toolpath patterns. The compared toolpath patterns are normal zigzag, smooth zigzag, normal spiral, smooth spiral and fishtail spiral. The results show that the optimal toolpath pattern is dependent on part geometry, physical characteristic of used CNC machine tool (accelerator and decelerator, continuous path, look ahead, and etc.) and cutting conditions (tool diameter, feedrate, and etc.). The developed comparing method has been implemented in Visual C++. Many examples are used to illustrate the developed method.