Simulation of micro-cutting in the process of finishing anti-friction non-abrasive treatment

Abstract

The influence of the shapes and sizes of microroughnesses on the creation of favorable conditions for micro-cutting of antifriction material by modeling the contact interaction of microroughnesses with the treated surface during the finishing antifriction non-abrasive treatment (FANT) is studied in the work. It is shown that the formation of the anti-friction coating FANT depends on the conditions of contact interaction of the tool with the treated surface, and the shape and size of the microroughness determine the quality of the resulting coating. In the study of FANT at the stage of micro-cutting, a similarity and dimension theory method was used, according to which cutters made of gray cast iron SCh20 were made, the geometry of the cutting part of which simulated a separate microroughness of the surface of the workpiece with different front cutting angles. As a contacting surface and coating material used brass L63. The micro cutting process is considered as a low-temperature process of deep plastic deformations with a predominance of a simple shear of the processed material in the chip formation zone according to the free orthogonal cutting scheme. A scheme for the interaction of microroughness with the treated surface is constructed with the friction-mechanical method FANT. It has been established that the cutting blade of a cast-iron micro-cutter wears out intensively in the process of interacting with a brass surface, and the process of changing the geometry of the tip of the cutter occurs in accordance with the principle of adaptability of the entire system of the cutter - the part according to which the minimum of micro-cutting energy is realized. It is proved that with a decrease in the cutting front angle, the blunting radius of the cutting edge increases, and the actual cutting depth and the volume of microchips decrease. Reducing the cutting front angle contributes to the strain hardening of the rubbed material, which reduces the chip formation process of the antifriction material. In order to intensify micro-cutting and obtain a high-quality FANT coating, single microroughnesses of the treated surface should have a cutting front angle γ ≥ 0°. The obtained experimental data and simulation results made it possible to present contact interaction diagrams of the tool with the surface being machined for various angles during FANT at the stage of microcuts, and also to establish the basic laws of their parameters. An analysis of the characteristic microcutting patterns in FANT by the friction-mechanical method made it possible to recommend the parameters of the initial surface microrelief, thereby creating favorable conditions for micro-cutting of the antifriction material and to improve the quality of the formation of the antifriction coating.