Cross-Scale Identification For Friction Damage On The Flank Of High-Energy-Efficiency Milling Cutter And Its Evolution Characteristics

The intense strain for milling cutter is caused by the collision,impact of milling cutter and the workpiece under the high-speed impact load.The compound of milling cutter body peels off under the accumulation of multiple impacts.The falling particles move along the direction of friction load,resulting in micro damage such as deformation and accumulation on the tool fiank.The above processes lead to increased and changing wear of the cutter tooth of milling cutter,which directly affects the life of the milling cutter.Under the milling cutter vibration,axial and radial errors of the cutter tooth,the magnitude and direction of the macroscopic load on the flank of cutter tooth changes with the transient contact relationship of the cutter-workpiece mesoscope.The type of damage,degree of damage and the formation and evolution of the transient wear area of the flank of cutter tooth are diversified.Therefore,the cross-scale identification of frictional damage on the flank of energy-efficient milling cutter tooth is the key to predict the wear level of milling cutters and improve the life of milling cutters.This paper is supported by the National Natural Science Foundation of China(NSFC)project "Multi-scale coupling mechanism of nonlinear frictional dynamics wear of high-feed milling cutter(51875145)" to carry out the research on the method of cross-scale identification of the wear on the tool flank.The evolution process of friction and wear on the flank of high feed milling cutters under vibration is revealed.The instantaneous posture of the milling cutter and cutter tooth,the instantaneous friction velocity on the flank is studied,and the change characteristics of friction stress under the action of milling vibration.Combined with milling vibration and friction and wear experiments on the tool flank.The results of instantaneous thermal coupling field analysis of the tool flank is used,using continuum mechanics and molecular dynamics,the structural deformation and failure characteristics of the tool flank at different time and spatial scales under frictional loads are analyzed.A multi-scale characterization method for instantaneous friction damage behind milling cutters is proposed.In order to identify the formation and evolution of mesoscopic structure deformation and damage of milling cutter,the characterization method of variation of super-cell structure under friction load is proposed.Super-cell model is constructed for the interface of the milling cutter cutter-workpiece frictional sub-interface,and the results of the super-cell configuration change are obtained by loading the macroscopic load to the mesoscopic through the load transfer method across scales.Using the mechanical property parameters such as potential energy and modulus of elasticity and characteristic parameters describing the internal defects of the super-cell structure such as the number of holes and the volume of vacancies,the influence of the damage parameters on the mesoscopic structure deformation is obtained and the mesoscopic friction dynamics of the milling cutter is characterized.The identification method of the change characteristics of the super-cell structure under friction load is proposed.The super-cell model of the friction interface of the milling cutter is constructed.The formation and evolution of the deformation and failure of the mesoscopic structure of the milling cutter are studied by using the crossscale transfer method of the macroscopic friction load.The internal defects and mesoscopic structural deformation of the super-cell structure are described by using the parameters such as the potential energy of the super-cell,the number of holes,the vacancy volume and the elastic modulus,and the formation and evolution characteristics of the mesoscopic friction damage on the tool flank are revealed.Aiming at the formation and evolution process of mesoscopic damage on the tool flank,the variation characteristics of super-cell configuration and the characteristic time of nucleation and expansion are studied.The coupling and competition effects of mesoscopic damage nucleation and expansion rate process are characterized.The evolution motivation of defects such as super-cell vacancies and microvoids on the flank is revealed.The cross-scale identification method of friction damage on the flank is proposed and verified by experiments.The results of response characteristics analysis show that the competition and coupling relationship between the mesoscopic damage degree,damage nucleation and expansion rate of the milling cutter also change after the position of the flank changes.There is a longer expansion rate process near the side of the cutting edge,and the degree of friction damage is more serious.By using scanning electron microscopy and energy spectrum analysis,it is confirmed that the simulation results of the friction damage degree of the tool flank are in good agreement with the experimental results.