INFLUENCE OF RADIAL DEPTH OF CUT ON INITIAL CONDITIONS OF OSCILLATIONS DURING END-MILLING OF THIN-WALLED PARTS

Abstract

Milling is widely used in mechanical engineering and other industries. Optimization of this process can lead to improved quality of machined parts, increased productivity and reduced wear of equipment. The paper investigates an important aspect of the milling process, namely the influence of radial depth of cut on the properties of the tool-part technological system (TS) and the amplitude of vibrations during machining. Vibrations can be a direct cause of reduction of quality and accuracy of machined parts. When the amplitude of vibrations increases, their impact on accuracy becomes critical. The analysis of studies of up and down end-milling with different radial depths of cut in the third speed zone of oscillations shows that with increasing radial depth of cut the cutting time and maximum thickness of the cut layer increases. This affects the length of the cutting surface and the character of the workpiece oscillations during up and down-milling. The length of the cutting surface determines how many waves of accompanying free oscillations of the TS and with what intensity will leave their trace on the cutting surface. In up-milling, the thickness of the cut layer increases with increasing radial depth of cut, while the amplitude of the accompanying free oscillations TS and their period decrease. At down milling the thickness of the cut layer decreases, and the amplitude of accompanying free oscillations of the TS and their period increase. A common characteristic feature of up and down-milling is the shaping of the machined surface in the cutting zone with a small thickness of the cut layer. In up-milling, this area is at the beginning of cutting, when the oscillation conditions are the same for all radial cutting depths. Therefore, the machined surfaces after up-milling with different radial cutting depths have close values of pitch and undulation height. At down-milling with increasing radial depth of cut, the amplitude of accompanying free oscillations of the TS in the profiling zone increases. This leads to an increase in the pitch and height of undulations on the machined surface. When milling in the third speed oscillation zone, it is necessary to select the radial depth of cut so that the cutting time is less than the period of the accompanying free oscillations of the TS. This will avoid undesirable oscillations and improve the quality of machining. The paper provides important results and recommendations for optimizing the milling process, considering the influence of radial depth of cut on TS properties and vibration amplitude. These findings may be useful for professionals working in the field of cutting materials processing to improve the efficiency and quality of production processes.