Identification Method For Unsteady Friction Characteristics Of Flank Face Of High Efficiency Milling Cutter

Under the action of high-speed and intermittent cutting load,the contact friction between the flank surface of the milling cutter and the machined transition surface is time-varying,which directly affects the friction and wear resistance of the milling cutter and the machined surface morphology.The existing identification methods of the friction and wear characteristics of the flank face of the milling cutter focus on the variation characteristics of the specific friction variables and the overall cumulative wear of the flank face of the cutter teeth.The dynamic distribution characteristics of the instantaneous friction of the flank face of the cutter teeth need to be revealed.In this paper,under the support of the National Natural Science Foundation of China ’s ’ multi-scale coupling mechanism of nonlinear friction dynamics and wear of high-efficiency milling cutters(51875145)’ and the key project of Heilongjiang Natural Science Foundation ’ orderly multi-source flow evolution mechanism and key technology of high-efficiency milling heavy machine tool basic components(ZD2020E008)’,the unsteady characteristics of instantaneous friction velocity,friction energy consumption,friction stress and friction coefficient of high-efficiency milling cutter tooth flank are studied,and the influence of milling cutter vibration on friction characteristic variables is identified.Considering the influence of cutter tooth error and milling vibration,the instantaneous contact relationship between the flank face of the cutter tooth and the machining transition surface is studied,and the calculation method of instantaneous friction velocity and instantaneous contact stress of the flank face is proposed.Combined with the cutting experiment of high efficiency milling cutter and the analysis results of thermo-mechanical coupling field,the variation characteristics of the instantaneous contact friction boundary between the flank surface and the machining transition surface are studied.According to the energy conversion relationship between the atoms at the tool-work interface,the instantaneous friction energy consumption,instantaneous friction coefficient and instantaneous friction stress calculation model of the flank face are constructed to obtain the time-domain variation characteristics of the friction characteristic variables of the flank face of the milling cutter.The time domain variation characteristic parameters of friction variables at different positions of the flank face of the cutter tooth are compared and analyzed,and the time domain unsteady characteristics of friction variables are studied.Through Fourier transform,the spectrum and power spectrum analysis of the instantaneous friction variable of the flank face of the cutter tooth are carried out,and the composition and proportion of the unsteady characteristic components and the frequency range of the main components are revealed.The power spectrum entropy is used to quantitatively express the complexity of the power spectrum of the instantaneous friction variable of the flank face of the cutter tooth.The cross-correlation function of the milling vibration and the instantaneous friction characteristic variables of the flank face of the cutter tooth is constructed.Using the variation characteristics of the cross-correlation coefficient with the cutting cycle of the milling cutter,the vibration components along the feed,cutting width and cutting depth of the milling cutter are revealed.The variability of the influence of instantaneous friction velocity,friction energy consumption,friction coefficient and friction stress on the flank face of the cutter tooth.The identification method of unsteady friction characteristics of flank face of milling cutter is proposed.This method is used to analyze the response characteristics of time-frequency characteristics of friction variables of flank face of milling cutter under different process parameters.Combined with the experimental results of vibration and wear of milling cutter,the variation of frequency domain characteristic parameters of friction energy consumption and the degree of chaos of flank face of milling cutter in multiple cutting cycles are used to analyze the position variation characteristics of flank face,and the results of cumulative wear morphology detection and wear non-uniformity distribution analysis at different positions of flank face of milling cutter are used to verify the validity of the analysis model and identification method of unsteady friction characteristics of flank face of milling cutter.