Research On Heat Transfer Mechanism Of High-speed Dry Grinding Of Core Block Ceramic Based On Fractal Theory

The core ceramic material has the characteristics of high strength and poor thermal conductivity.The grinding energy of the core block ceramic produced by the resin diamond wheel dry grinding is almost converted into grinding heat,and the temperature in the grinding zone is rapidly increased,which greatly affects the life of the grinding wheel,the processing cost and the quality.Therefore,it is of great theoretical and practical significance to study the formation and distribution mechanism of grinding heat of core block ceramic dry grinding and the temperature field in the grinding zone,which is also the key to perfect the processing technology of core block ceramics.This paper mainly researches the grinding heat of the core block ceramic mat erial grinding by resin diamond wheel.In the research process,the equivalent thermal conductivity of the grinding wheel and the heat distribution coefficient of the workpiece are determined based on the fractal theory;the dry grinding experiment of the ceramic block simulation of the core block is conducted;and the temperature field in the grinding zone is numerically simulated.The specific research work includes the following aspects:(1)Firstly,three-dimensional surface profiler is used to collect the topographic information of the grinding wheel.The digital filter method is used to process the obtained wheel topography information,and the topography of the grinding wheel is reconstructed.Then using the box dimension method to calculate the fractal dimension of the grinding wheel at different grinding depths,the equivalent thermal conductivity of the grinding wheel at different grinding depths are calculated based on the parallel heat conduction model,Finally,M.C.Shaw's grinding zone heat distribution model is used to calculate the heat distribution coefficient of the workpiece based on the equivalent thermal conductivity,equivalent specific heat capacity,and equivalent density of the grinding wheel and workpiece.(2)The dry grinding technological experiments of ceramic block simulation pieces are conducted,and the grinding speeds and grinding temperatures at different feed depths v_w,different grinding depths a_p are measured,the effects of v_w and a_p on the experimental results are analyzed.The experimental results show that within a certain range of grinding depth,the grinding temperature of the workpiece surface has a downward trend with the increase of the grinding depth.(3)Based on the heat distribution analysis of the workpiece and the experimental results,an arc-shaped moving heat source model was used to simulate the temperature field in the grinding zone of the cup-shaped grinding wheel in the ANSYS environment.Under certain conditions,the simulation and experiment consistency are better.