Design Of End Milling Cutter With Unequal Tooth Pitch For Manufacturing

As a modern advanced manufacturing technology,high-speed cutting has significant advantages.Milling occupies a large proportion in cutting.Unequal pitch end mills are widely used in high-speed machining because of their unequal inter tooth angles,which can reduce the vibration in the process of milling and have good dynamic performance.However,the characteristic of unequal tooth pitch causes the offset of the center of mass of the end milling cutter.Under high-speed working conditions,it will cause a certain centrifugal force,cause the self-excited vibration of the cutter,and reduce the service life of the end milling cutter and the surface quality of the workpiece.At this time,the stability of unequal pitch end milling cutter becomes worse than that of equal pitch end milling cutter.Therefore,we must pay attention to the dynamic balance of unequal pitch end mills.At the same time,tool grinding technology also hinders the wide application of unequal pitch end mills.Therefore,on the basis of not sacrificing unequal tooth structure,how to improve the dynamic balance performance of this kind of tools and realize accurate grinding is of great significance.Therefore,on the basis of practical manufacturing,this paper optimizes and designs an unequal pitch end mill which tends to dynamic balance in theory,verifies the effectiveness of optimization through simulation and experimental means,and forms a high stability unequal pitch end mill design optimization grinding application integration technology,This provides technical support for the application and promotion of unequal pitch end milling cutter in high-speed milling.Firstly,using the reverse idea,with the help of coordinate system transformation and projection transformation,the grinding trajectory is studied,the grinding equation of unequal tooth pitch end milling cutter based on the manufacturing process is deduced,and the relative pose of bar grinding wheel and grinding wheel angle of end milling cutter are calculated,which lays a theoretical foundation for the next end milling cutter structure design optimization and subsequent tool actual manufacturing.Secondly,based on the specific shape of chip holding groove end section of integral unequal pitch end milling cutter deduced by using the principle of dynamic balance,the centroid offset equation of integral unequal pitch end milling cutter is calculated;Particle swarm optimization algorithm is used to optimize the chip holding groove,and the removal amount of chip holding groove is controlled by changing the grinding wheel angle,so as to reduce the centroid offset of end milling cutter;The accuracy of the equation is proved by Solid Works quality analysis function to verify the effectiveness of optimization.Then,the unbalanced end milling cutter with equal chip holding groove and the end milling cutter model with relative balance of unequal chip holding groove are imported into the simulation software for modal and harmonic response analysis.The influence of the mesh element size on the simulation results is discussed,the most ideal mesh element size is selected,the results are obtained and compared.By comparing the vibration mode,natural frequency,maximum deformation and response displacement of the two end milling cutters under the same mode,it is verified that the dynamic balance of the end milling cutter is improved after optimization.Finally,the scheme of manual grinding path is selected in the tool grinding simulation software numroto,and the specific parameters of the relative pose of the bar grinding wheel and the rotation angle of the grinding wheel are input to simulate the specific trajectory of grinding end milling cutter.Two unequal pitch end milling cutters are ground on a five axis grinder.The accuracy test and dynamic balance experiment of two end milling cutters are carried out to verify the accuracy of grinding and centroid offset equation.A comparative milling experiment is carried out under high-speed working conditions to reveal the influence of centroid offset on the machining stability of unequal pitch end milling cutter,which provides evidence support for the design and optimization of end milling cutter in this paper.