RESEARCH OF OSCILLATIONS DURING END-MILLING AND THEIR INFLUENCE ON THE FORMATION OF THE MACHINED SURFACE

Abstract

Purpose. Study of oscillations that occur during end-milling and their influence on the formation of the processed surface. Research methods. The research was carried out using the experimental method, in which oscillograms of part oscillations were recorded with the allocation of cutting time during milling. Basic fragments of oscillograms were studied using the analytical method, on which the parameters characterizing the milling process were measured, and their relationship with the processed surface was determined. Results. When milling with low spindle rotation frequencies, with down and up direction of feed, the part is affected by various types of oscillations, which are characteristic of the first and second speed zones of oscillations. During up and down end-milling, only forced oscillations operate in the first high-speed oscillation zone. In the second speed zone during up milling, the accompanying natural vibrations of the technological system are superimposed on the forced oscillations. It has been experimentally and analytically proven that the resulting deviation from the position of elastic equilibrium of the first wave of the accompanying oscillations affects the pitch and height of the waviness of the processed surface, which confirms the connection between the dynamics of end-milling and shaping. Scientific novelty. The impact of accompanying free oscillations of the technological system during cutting on the formation of the processed surface is evaluated using parameters characterizing the dynamics of end-milling. Practical value. The obtained results prove the influence of the cutting speed on the amplitude of the accompanying free oscillations of the technological system and provide an opportunity to choose cutting modes that ensure vibration stability of milling.