Theoretical model for CNC whirling of screw shafts using standard cutters

Widely increased use of screw components with complex helical surfaces in contemporary machinery makes a huge demand for high-efficiency fabrication of these components. In this paper, a typical whirling process is introduced and the helical surface of a screw shaft is mathematically modeled based on its axial section profile, which is depicted usually by a number of sampled points. Following this, a theoretical approach is proposed to whirling the screw by using standard cutters, aligned with a detailed investigation into related issues including calculations of the cross section profile and the cutting tool location points. In this approach, the helical surface can be generated according to the shaft cross section which is used as the envelope of the cutting-tool motions in the machining process. The machining error is also analyzed with focuses on the axial- and cross section scallop height. Finally a case study is presented, which demonstrates the whole process including CAD models and cutting tool in-process positioning geometry data. The error distribution of the machined component along the profiles is also simulated.