Tool path generation for milling of the screw surfaces with varying pitch using standard cutters

Screw surfaces have gained more and more applications in industry. While, they are difficult to be machined due to their complex geometry, especially the ones with varying pitch. To effectively machining these surfaces using standard cutters, a tool path generation method is proposed which also includes the tool nose radius compensation and path optimization. The tool path generation is based on the model of the screw surfaces and the coordinate relationship between the cutter and workpiece. The tool nose radius compensation is achieved via coordinate transformation and local fitting using moving least squares method. And the tool path is optimized by data interpolation of the reference surface which generated by the reference points that generated from the tool nose radius compensation. After the optimization, the complexity of the path can be effectively reduced leading to smaller acceleration of each motional axis. The machining results further validate the proposed methods. It also can be seen that the proposed method also has the advantages of easy application and good generality.