RESEARCH ON THE INFLUENCE OF THE COATING OF THE CUTTING PART OF THE CUTTER ON VIBRATION DURING TURNING

Purpose. The aim of the work was to investigate the influence of the coating of the cutting part of the cutter on vibrations during turning. Research methods. The research was conducted by an experimental method, in which oscillograms of oscillations of the cutting edge of the cutter-oscillator were recorded. The analytical method was used to study the oscillograms on which the parameters of the oscillatory system of the cutter-oscillator were measured, which characterize the law of motion of the cutting edge during self-oscillations. Results. The results of the study confirmed that when applying a coating to the cutting part of the cutter, the friction coefficient in the tool-part contact zone decreases. This leads to a change in the chip formation conditions and is reflected in a decrease in the chip shrinkage coefficient by 1.2…1.35 times. Analysis of the oscillograms of the oscillation of the cutting edge of the cutter-oscillator showed that the application of the coating almost did not change the static deviation. At the same time, the amplitude of the oscillations decreased by 1.1…1.3 times. The change in the oscillation of the cutting edge was reflected in the vibration pattern of the machined surface. When using a cutting insert with a coating, the surface roughness decreased by 1.05…1.17 times. Scientific novelty. The obtained results confirm the influence of the friction effect on the excitation and maintenance of self-oscillations. However, taking into account the small magnitude of the change in the intensity of oscillations with a significant change in friction conditions, it can be concluded that the influence of the friction effect is much smaller compared to the regenerative effect. Practical value. The obtained results prove the influence of friction conditions in the tool-part contact zone on the intensity of self-oscillations during turning and provide an opportunity to choose the coating of the cutting part of the tool to reduce vibrations.