Cross-scale Identification Method Of Friction And Wear Boundary Of Flank Face Of High-feed Milling Cutter

During the milling of titanium structural parts with high-feed milling tools,under the combined action of cutting load and cutting impact load,a small random vibration will occur between the milling cutter and the workpiece,and the internal structure of the milling cutter teeth is prone to micro-damage.The above-mentioned effects will evolve the damage degree of the cutter tooth to a macro scale under the condition of cyclic reciprocating cutting.Under the continuous and intense friction between the cutter tooth and the workpiece,it will eventually lead to severe wear of the milling cutter and decrease in service performance,which seriously restricts the processing efficiency and processing surface.Further improvement in quality.In addition,due to the random vibration between the cutter and the workpiece and the uneven distribution of the cutter tooth installation error,the contact area and angle between the tooth and the workpiece have been changing.The above factors make the flank face of the milling cutter tooth The degree of damage at each point is inconsistent,and there is uncertainty in the formation and expansion of the fretting corrosion of the flank face of the milling cutter tooth.Therefore,the effective identification of the cross-scale evolution process of milling cutter tooth surface damage and its friction and wear boundary is the key to accurately predict the wear degree of milling cutter tooth surface and improve the overall service life of milling cutter.Supported by the National Natural Science Foundation of China(NSFC)project ' Multi-scale Coupling Mechanism of Nonlinear Dynamic Friction and Wear of High Feed Milling Cutter(51875145)',The research across different scales on the friction and wear boundary of the tooth surface of highfeed milling cutter was carried out.It reveals the cross-scale formation and evolution of the tooth surface friction and wear boundary.To investigate to study the formation process of fretting corrosion boundary of milling cutter tooth surface,high feed milling experiments were carried out.The fretting corrosion state of milling cutter tooth surface under different milling parameters was obtained,and then puts forward that the measurement method of fretting corrosion boundary of milling cutter tooth surface.Indicates the boundary range of the fretting corrosion of the tooth surface of the milling cutter;the identification method of the characteristic points of the tooth surface of the milling cutter is proposed.The transformation matrix of the milling cutter cutting motion coordinate system is established,and the solution model of the instantaneous position angle of the cutter tooth is proposed.The characteristics of the transient cutting attitude change on the back of the tooth are obtained.A finite element analysis of the thermal-mechanical coupling field of the flank face of a milling cutter is carried out.Based on the distribution of the thermalmechanical coupling field at different positions of the flank face of the cutter tooth,a solution method for the normal stress and friction stress of the flank face of the cutter tooth is proposed to establish the macroscopic load.The boundary conditions provide a theoretical basis.Based on the element content and crystal structure parameters of the flank material of the cutter tooth,the super cell model of the flank surface of the milling cutter tooth is established;the super cell model is optimized by the energy minimization method;the high temperature relaxation method and rapid condensation are adopted Method to make the atoms in the supercell reach a stable state and meet the requirements of mechanical properties.According to the theory of molecular dynamics,a cross-scale transfer method of milling cutter cutting load is proposed to realize the cross-scale effective correlation of macro-mesoscopic load.The molecular dynamics simulation of the mesoscopic damage of the flank face of the milling cutter tooth was carried out to study the damage formation and evolution characteristics of the supercell mesoscopic structure of the flank face of the cutter tooth.According to the results of supercell stress loading,the criteria for local damage and integrity damage of the supercell on the flank surface of the cutter tooth are constructed.Select the characteristic points of the flank face of the cutter to determine whether the mesoscale of the characteristic points of the flank of the cutter is damaged,the fretting corrosion boundary of the milling cutter tooth is characterized,and the shape of the fretting corrosion boundary of the cutter tooth is compared and analyzed in the medium scale to verify the correctness of the crossing dimension identification method of the fretting corrosion boundary of the flank of the cutter tooth.The response surface model of macro or meso structure damage of flank face of milling cutter is established by response surface methodology,and the relationship between the influencing factors of meso structure damage of flank face and the response variable of flank face damage is studied.Analyze the response characteristics of the formation and evolution of the mesoscopic damage of the flank structure of the tooth under the interaction of the width of cut and the depth of cut.According to the basic principle of significance test,the significance probability of the factors affecting the flank structure damage of the cutter tooth is solved,the sensitivity of the factors affecting the flank structure damage is analyzed,and the selection of process design variables to control the damage of the flank structure is given order.