Analytical modeling on 3D chip formation of rotary surface in orthogonal turn-milling

Orthogonal turn-milling is a relatively new process technology, the coupling turning and milling processes together and enjoying the advantages of both. However, to the best knowledge of the authors, few studies on the chips of the orthogonal turn-milling have been reported, although the understanding of the chips is important when studying turn-milling mechanism, machining heat and tool wear. In this paper, the analytical models of 3D chips (under both centric and eccentric situations) are proposed based on the orthogonal turn-milling principle and the mathematical expressions of chip thickness and height are obtained considering both side and end cutting edges. Based on the models, numerical analysis is performed to understand the relationships between chip dimensions and cutting parameters. To verify the proposed models and numerical results, the validation experiments are conducted. The comparison shows the consistency between theoretical and experimental results in terms of chip geometries and volumes under different cutting speeds and feed rates. Some findings are presented based on this study, which might provide a theoretical foundation and reference for the orthogonal turn-milling mechanism research.