Study On The Compound Alternating Moving Heat Load And Transient Grinding Temperature Field Of Large Spiralangle Groove Grinding Wheels

Grinding is one of the main methods of precision manufacturing,which plays a very key role in the development of aerospace,rail transit and other high-end manufacturing industries,high grinding temperature is an important reason for the surface quality of the grinding process.The large spiral angle groove grinding wheel can improve the heat transfer performance in the grinding arc area and thus improve the surface quality,which is an effective way to break the technical bottleneck of high temperature of traditional grinding process.However,during the grinding process,the contact area between the large spiral angle groove grinding wheel and the workpiece is not stable,and the path and process of dissipation of grinding heat generated at the interface of the contact area will become extremely complex,which makes it extremely difficult to study the distribution and dynamic change mechanism of the grinding temperature field.Therefore,the study of the transient grinding temperature field distribution of large spiral angle groove wheels and revealing its dynamic change mechanism is a key problem that needs to be solved.Based on this,this paper takes the surface grinding of groove wheel with large spiral angle as the research object.The relationship between the numerical geometry model of the big spiral Angle grooved grinding wheel and the workpiece movement was analyzed,the compound alternating moving thermal load model in the grinding arc was established,and the change of the transient grinding temperature field of the big spiral angle grooved grinding wheel was investigated.The effectiveness of the numerical model was verified by experiments.The main research work of this paper is as follows:1.Numerical modeling of the grinding wheel geometry based on the wheel kinematics during grinding.Spiral lines are created on the grinding wheel surface to create a grinding wheel with a large spiral angle groove that can be varied in terms of the number of spiral lines,the width of the groove and the size of the spiral angle.The discrete points of the "contact zone" and "non-contact zone" are calculated at different points in the grinding arc of a large helical gullet wheel by dispersion of the wheel in the circumferential direction and by cutting the workpiece with a flaky cutting edge.Numerical analysis of the exact position of the load to be applied in the grinding arc during the plunge,full cut and cut-out phases.2.The maximum undeformed chip thickness is calculated based on the state of contact between the abrasive grain and the workpiece in the grinding arc during the grinding process.The number of grinding grains involved in the grinding of a large spiral groove wheel is analysed and the number of effective grinding grains involved in the grinding arc is obtained,leading to the calculation of the grinding forces.Based on the magnitude of the grinding force,the heat flow density transmitted to the workpiece is obtained through the heat distribution relationship in the grinding arc zone,and combined with the calculated convective heat transfer coefficient,a composite alternating moving heat load model is established.3.A finite element analysis model of the transient grinding temperature field of a large spiral fluted grinding wheel is established,and a composite alternating moving heat load model is applied to it based on the discrete points of the "contact zone" and "non-contact" of the analysed grinding arc area to study the variation of the transient grinding temperature field of the large spiral fluted grinding wheel.To compare and analyse the variation of grinding temperature on the workpiece surface of ordinary grinding wheels and large spiral angle groove wheels and the effect of grinding temperature on different depths from the workpiece surface,and to vary the surface parameters of groove wheels to study the effect of different surface parameters on the grinding temperature field.The results show that the maximum temperature of grinding with a large spiral angle groove wheel is about 24.5% lower than the maximum temperature of grinding with a common wheel under the same grinding process parameters,that the range of influence of the grinding temperature of a common wheel is greater at different depths from the surface of the workpiece,and that increasing the spiral angle,the number of spiral lines and the width of the groove will reduce the grinding temperature of the groove wheel.4.An experimental platform was built to study the variation of grinding temperature of 718 H steel,with thermocouples placed in the workpiece to measure the grinding temperature by means of an oscilloscope.A comparison was made to verify the temperature variation of the finite element analysis of the large helix angle groove wheel and the experimental process,and to verify the variation of grinding temperature on the surface of the workpiece and at different depths from the surface.The results show that the theoretical model created is in good agreement with the measured experimental data.