МАТЕМАТИЧЕСКОЕ МОДЕЛИРОВАНИЕ МИКРОВОЛНОВОГО НАГРЕВА ПОЛУФАБРИКАТОВ АБРАЗИВНОГО ИНСТРУМЕНТА

Abstract

The authors noted the advantages and disadvantages of microwave heat treatment of semi-finished abrasive tool (AT) and described the method of microwave heat treatment of semi-finished AT using heat insulation of heat units, which ensures uniform heating of the stack of semis. The article represents the physical model of microwave heating of AT bakelite bonded semis in the thermostat, which is the base for construction of mathematical model and determination of initial and boundary conditions. The authors specified the dependencies of thermal and physical characteristics of bakelite bonded semi-finished AT on temperature. The authors determined experimentally the dependence of specific capacity of heat energy released and absorbed in the process of AT polymerization by means of exothermic and endothermic effects on the time of heat treatment, carried out a numerical simulation of the microwave heating of semi-finished AT using the finite-element method in the NX 7.5 software environment. During this simulation, heat emission sources and the dependences of their specific capacity changes on the time are designated, initial and boundary conditions are given in accordance with the designed mathematical model. The article presents the results of numerical simulation in the form of temperature field in the stack of semi-finished AT. The most effective heat-insulator is selected on the basis of the analysis of models of microwave heating of semi-finished AT heat-insulated using various materials. During the microwave heating of AT semis using the radio transparent insulation the authors discovered the significant reduction in the temperature gradient. By means of numerical simulation of microwave heat treatment, the modes providing the required rates of heating of AT semis at various stages of the heat treatment cycle are revealed. Using these modes, the authors carried out the experimental study of the influence of heat insulation on the uniformity of AT semis heating within the microwave field.