ВЛИЯНИЕ ТЕХНОЛОГИЧЕСКИХ ФАКТОРОВ НА ЛОКАЛЬНЫЕ ТЕМПЕРАТУРЫ ПРИ ШЛИФОВАНИИ С НАЛОЖЕНИЕМ УЛЬТРАЗВУКОВЫХ КОЛЕБАНИЙ

Abstract

The application of ultrasonic vibrations (USV) power is one of the means for heat depression of the grinding process. However, the existing studies do not reveal the mechanism of USV influence on the local temperatures. To identify the significance of technological factors influencing the temperature of ultrasonic assisted grinding process, it is necessary to develop physical and mathematical models for heat-transfer factor calculation, the methodology, the algorithm and the software for the local temperatures calculation, and to carry out the numerical simulation of temperatures. The author specified the factors having prevalent influence on the local temperatures during ultrasonic assisted grinding and gave the dependencies for calculation of the lubricating-cooling fluid motion speed in the area of contact of a grinding wheel with a workpiece, lubricating-cooling fluid consumption through the area of contact and the heat-transfer factor of work piece, abrasive grains and wheel bond to the lubricating-cooling fluid. The paper presents the results of numerical simulation of the local temperatures in the area of contact of a grain with a workpiece and a chip during micro-cutting by the first of the subsequently working grains. When applying USV, the temperatures reduce mostly in the result of the change of the strain-stress state in the treatment area due to the strength characteristics degradation including the tensile strength of a workpiece material and the change of kinematics of the workpiece material micro-cutting by the single abrasive grains of a grinding wheel. The increase of consumption of lubricating-cooling fluid through the treatment area and the intensification of its cooling action influence the local temperatures insignificantly. The author identified the influence of the USV parameters (amplitude and phase) on the local temperatures change depending on the duration of contact of a grain with a workpiece. As a result, the degree of technology factors influence on the local temperatures during the ultrasonic assisted grinding was established analytically for the first time. The author determined that the USV application allows reducing local temperatures by a mean of 12 … 24 %.