Ultra High-Speed Metal Cutting Mechanism with Shock Waves

Abstract

A dynamic explicit thermo-elastic plastic FEM simulation is established in order to clarify ultra high-speed metal cutting mechanism in detail. Geometrical and thermal penalty methods are applied to the chip-tool contact problems. The node separation technique is used for the chip generation. When cutting speed exceeds the speeds of plastic waves, the shock waves are developed ahead but close to the rake face. Especially when the cutting speed is much higher than the speeds of plastic waves, the shock waves can be seen clearly. Since the shock waves induce the high levels of hydrostatic stress, the cutting force increases rapidly with cutting speed, resulting in very high levels of normal stress on the rake face though the shear angle rises up to 40 degrees.