Study On The Grinding Force Variation And Its Influence Of Helical Flute Of End Mill

The spiral groove is an important part of the end mill,which has important influence on strength,stiffness,geometric parameters and service life of mill.The torque generated during the grinding process of the spiral groove can cause the milling cutter deformed,which affects the manufacture of high precision mills.Based on the research and production status of spiral groove of mills at home and abroad.Knowledge of differential geometry,grinding principle,material mechanics and so on,the theoretical analysis and ANSYS Workbench simulation analysis are used to study on torque variation and its influence in grinding process,which has a strong practical significance for the manufacture of high-precision end mill.Firstly,the contact line equation,the mathematical model of the axial truncation of the helical groove grinding of the end mill and the mathematical model of the front angle,the core thickness and the blade width of the end mill were established by using the envelope principle.The equal chord length micro-segmentation of the contact lines was carried out by the parameter micro-segmentation method.The surface grinding forces in the grinding process of the end mill were equivalent to several plane grinding forces and be superimposed.The force model in the grinding process of the helical groove of the end mill was obtained,and the calculated grinding installation parameters were taken into the grinding force model to obtain the calculation data of the main grinding force and the deep shear resistance model.Secondly,the grinding torque model in the grinding process of the end mill was established,and the calculation data of the grinding moment model of the origins of the grinding wheel and the milling tool were calculated respectively.The results show that the calculated data of the torque model were in good agreement with the experimental results,and the torque model of the grinding force was verified by the comparison of the torque on the ZG axis(the torque produced by the spindle)and experimental results of the five-axis CNC WALTER tool grinder.Thirdly,according to the theory of material mechanics,the bending,twisting and compression deformation of the end mill caused by the grinding torque were calculated.The results were compared with the simulation results of ANSYS Workbench.It was found that the deformation results of the end mill calculated theoretically was consistent with the results of the simulation analysis.Change of end mill front corner,core thickness and blade width caused by deformation was analyzed furtherly.The results showed that the deformation of the end mill caused front axle to decrease,the core thickness to increase,the blade width to increase.It was found that the mass eccentricity was produced during the grinding process of the milling cutter.The influence of effect of centrifugal force produced by mass eccentricity on bending deformation and dynamic balance quality of end mill is was also analyzed.And centroid deviation produced when the spiral groove is not uniformly distributed was analyzed.Finally,the grinding wheel must be dressed continuously during the grinding process of the end mill,thus the influence of grinding wheel dressing on the grinding force and geometric angle of the cutter is studied.Within the scope of the study on the grinding depth,the angle of the front angle remains unchanged and core thickness increases while the blade width decreases compared with unfinished grinding wheel dressing;with the size decrease end face of the grinding wheel,The grinding force and grinding torque during the grinding process are reduced linearly and the bending,twisting,extrusion deformation of the end mill are also decreased linearly.In this paper,the grinding force and torque variation and its influence of the grinding wheel are analyzed in detail.Some research conclusions are negligible for the manufacture of ordinary end mill,but for the manufacture of helical groove in high speed and high precision tools cannot be ignored.Therefore,The results are of great reference value for the manufacture of spiral groove of high precision cutter and high speed rotary tools.