Effect on cutting force in turning hardened tool steels with cubic boron nitride inserts

Numerical simulations of high-speed orthogonal machining were performed to study the finish hard-turning process as a function of cutting speed, feed, cutter geometry, and workpiece hardness. In the simulations, properties representative of AISI 52100 bearing steel, AISI H13 hot work tool steel, AISI D2 cold work steel, and AISI 4340 low alloy steel were assumed for the workpiece. Cubic boron nitride (CBN) or polycrystalline (PCBN) inserts are widely used as cutting tool material in such high-speed machining of hardened tool steels—due to high hardness, high abrasive wear resistance, and chemical stability at high temperature. Cutting forces and feed forces were determined in the numerical simulations. Among process parameters, cutter geometry and workpiece hardness, the feed has the most significant effect on cutting and feed forces. With same cutting conditions, turning AISI 4340 gets the highest cutting force while turning AISIS 52100 has the highest feed force and turning AISI D2 gets the lowest cutting force and feed force. The feed force appears to be a larger force component than the cutting force in the hard turning. Cutting force and feed force increase with increasing feed, tool edge radius, negative rake angle, and workpiece hardness. Results from simulations are compared to experimental results reported in the literature.