Integration of tool geometry in prediction of cutting forces during milling of hard materials

Knowledge of the cutting forces owing to a predictive model is very interesting with respect to the choice of a machine tool power, the cutting tools, the optimization of cutting conditions for a given machining operation or the control of the occurrence of vibrations. It could also be helpful in online wear monitoring during milling. As this technique is usually based on a limit level of the cutting forces, it could allow the number of long and expensive tests to be limited and the best tool geometry to obtain quasi-constant and low cutting forces, which lead to a reduced tool wear, and consequently, a better tool-life, to be found. The objective of this study is the prediction of the effects of the rake and helix angles on the cutting force variations, and to integrate it into a cutting relation. Tests were made on X38 CrMoV 5 (AISI H11) die and mould steel, with solid carbide milling cutters of various rake angles. A specific configuration has been used to create obliquity. Cutting forces were measured for various feed rates. The results have improved the cutting force model, making it possible to choose the optimal rake and helix angles in a particular machining operation.