Simulation And Experimental Research On The Mechanism Of High-Speed External Cylindrical Grinding

High-speed grinding can not only improve the processing efficiency, but also can improve the surface quality and has become today's trend in the field of sophisticated and efficient processing. However, due to the highly non-linear power, thermal, chemical and their coupling in high speed grinding process, it has a lack of sufficient knowledge for high-speed grinding mechanism, and can not control the effects of grinding process parameters, materials of grinding wheel and its performance on the grinding quality and efficiency with different workpiece materials, so to carry out the research on high-speed grinding mechanism, especially high-speed cylindrical grinding mechanism has important practical significance and practical value. Due to limitations of test equipment and instruments, the study of the mechanism in domestic high-speed cylindrical grinding with CBN grinding wheel is still in its infancy, so to carry out the simulation studies of high-speed CBN cylindrical grinding mechanisms to reveal the effect of grinding force, grinding heat and its thermo-mechanical coupling on surface quality, and even the related research on key components of high-speed grinding wheel spindle system to reduce the consumption of physics experiments, and further establish and improve high-speed cylindrical grinding theory seems particularly important.This dissertation described the research history and current situation of domestic and foreign high-speed grinding technology. According to the summation and deduction of the theory of cylindrical grinding, the cylindrical grinding research method based on thermo-mechanical coupling of high-speed cylindrical grinding simulation model using DEF0RM-3D software is proposed. After verifying the reasonableness of the model by the use of the experiments, it carried out the research on high-speed cylindrical grinding mechanism for 40Cr adopting the approach of the relevant experimental study, simulation analysis and the method of combining theoretical derivation. The main work includes:(1) Based on DEFORM-3D on a single diamond grain, it has systematically studied the cylindrical grinding process. According to the test results, the effects of grinding process parameters, specific grinding energy on grinding force, grinding temperature are analyzed. Simulation results show that: grinding force increases with the increase of grinding depth, decreases with the increase of wheel speed, in which grinding depth has the most significant effect; grinding force ratio has increased slightly as a grinding material removal rate increases; and specific grinding energy decreases with the increase of material removal rate and gradually tends to a stable value; grinding temperature increases with the increase of grinding depth, first increases and then decreases with the increase of grinding wheel speed, its changing regularity is basically same with the "Salomon" curve, and the workpiece speed has little effect on the grinding temperature; in a single grinding cycle, along the direction of grinding contact zone, the temperature increases with a significant gradient, reaches its maximum about the center of the arc, and then slowly declines; at the same time, it produces the greatest heat at the center of arc, and the shape of heat flux distribution can be approximated as a quadratic curve distribution.(2) Design cylindrical grinding pilot program, use MK 1432 / H CNC universal cylindrical grinding machine for associated tests. Use the existing surface grinding dynamometer, through the design and processing of measuring base, the three-axis force of the workpiece caused from cylindrical grinding process reaches the surface of the dynamometer, and thus for data collection; design temperature acquisition cards and home-made thermocouples workpiece.(3) High-speed cylindrical grinding test results are analyzed to verify the simulation model presented in this dissertation is reasonable. Engineering test results showed that:when v_s<80m/s, the variations of grinding force and grinding temperature re consistent withthe simulation results; when v_s> 80m/s, due to test equipment limitations, it can not be verifiedtemporarily.(4) The surface roughness test results after the grinding test of the workpiece showed that: the workpiece surface roughness value decreases with the increase of wheel speed, but the effect issmall, the changes of roughness value is basically smaller than 0.1μm ; workpiece surfaceroughness values increase with the increase of grinding depth, and decreases with the increase of workpiece speed, but the decreasing trend is more moderate.