NUMERICAL AND EXPERIMENTAL ANALYSIS OF CHIP FORMATION AT ULTRAHIGH CUTTING SPEED

The tendency of substantially increasing the cutting speeds in the cutting processes of metallic materials leads to an increase in the productivity of the machining processes. In order to ensure such increase, the regularities of the cutting characteristics at the high cutting speeds should be examined more closely. For the analysis of chip formation at high cutting speed, cutting simulations were used together with experimental investigations of the orthogonal cutting process. Kinetic machining characteristics and characteristics of the chip morphology were investigated by experiment and analysed for cutting speeds from 1.17 to 25 m/s and different geometries of the cutting wedge. In addition, the characteristics were simulated with the help of the developed 2D FEM cutting model. The parameters of the constitutive equation for the FEM model were determined by experiment at correspondingly high cutting speeds. This ensured a good agreement between experimentally determined and simulated machining characteristics. In particular, chip formation was analysed for the critical cutting speeds at which the chip flow changes into a periodically serrated chip flow. When analysing the distribution of strain and temperature in the shear zones and the chip, it showed that these characteristics change depending on cutting speed for different tool orthogonal rake angles of the tool wedge.