Research On Frictional Behavior Difference And Damage Trans-scale Characteristics Of Cutter Teeth In High Speed Milling Cutter

With the impact of intermittent load,the wear of the cutter has a significant influence on tool life and workpiece quality in high speed milling.Meanwhile,the internal energy of milling cutter is constantly changing in the uneven distribution of stress field.Plastic or brittle fracture damage of milling cutter components lead to the decrease of the safety and stability of milling cutter,which restrict on cutting efficiency of milling cutter.It has become a key problem to improve the efficiency,accuracy and reliability of milling cutter.In view of the problem of the increase of frictional behavior difference,which results in overdue service and premature retirement of milling cutters,the frictional behavior difference of flank faces of milling cutter teeth is studied under milling vibration.The solution and evaluation method of the difference of the tooth wear of the milling cutter is proposed to investigate the behavior characteristics of damage of high speed milling cutter components,and the cross scale correlation control method of the high speed milling cutter damage is proposed.The main content of this thesis includes the following parts:By analyzing the cutting contact angle and tool vibration of high speed milling cutter teeth,the contact relationship between the flank face and the machined surface is obtained to solve the the movement trajectory and the instantaneous cutting position of cutter edge.A model of the dynamic friction pair between the flank face and the machined transition surface is established.The dynamic characteristics of the friction process of the flank face of the milling cutter are revealed,the dynamic contact relationship between the flank face of the milling cutter and the friction pair on the machined surface,which reflected by the instantaneous contact vector between the flank face and the machined surface.It provides an analysis basis for further research on the difference of the flank face wear of milling cutter teeth under vibration.The cutting vibration characteristic parameters of milling cutter are extracted to identify the cutting periods of the cutter teeth.It is indicated from the analysis results of vibration behavior of cutter teeth in high speed milling that the vibration period of the milling cutter is different from that of the cutter passing period,which leads to the difference in the friction time behavior of the flank face of cutter teeth under the vibration condition.The instantaneous cutting state of the cutter tooth is identified through the cutting vibration time domain signal and the high-speed camera to obtain the location sequence and speed sequence of friction contact point of high speed milling cutter teeth.The dispersion analysis method and grey correlation analysis method are used to reveal the differences of the time-varying behavior of the vibration friction of the flank face.A method of the friction and time-varying behavior calculation and identification of cutter flank face is proposed and it is verified by wear tests of high speed milling cutter.The method can reveal the discrepancy of the flank wear of milling cutter teeth,and based on this,the formation mechanism of milling cutter damage is studied.In order to reveal the damage behavior characteristics of component materials of high speed milling cutter,a damage state model of the milling cutter is established,and the deterioration degree of the material properties of the milling cutter components under cutting loads is analyzed.Aiming at the locality,concealment and diversity of the milling cutter damage,the parts of the milling cutter,which are prone to damage,are extracted and analyzed through the load analysis of the milling cutter components by the finite element simulation in high speed milling.The Weibull distribution function is used to illustrate the uneven distribution of blade material properties of milling cutter components,and the formation and evolution characteristics of local damage of milling cutter are studied.The damage experiments of high speed milling cutter are carried out to illustrate the obvious differences in the local damage evolution process of the milling cutter components under different cutting parameters.In order to identify damage degree of milling cutter components,a judgment method of the damage behavior of high speed milling cutter is proposed.The damage of milling cutter is classified by analyzing the macro damage form of high speed milling cutter.The characteristic parameters of cutter tooth damage are extracted to study the macroscopic damage behavior by using finite element analysis method and adopting milling cutter damage model.Reasons of damage of milling cutter are revealed by analyzing the damage of different parts of milling cutter teeth from microcosmic level.An atom/finite element overlapping belt model of high speed milling cutter is used to reveal the motion process of milling cutter atoms.The entropy value algorithm for judging the damage of milling cutter is used to quantitatively describe the motion state of milling cutter atoms.The cross scale response characteristics of milling cutter damage were studied by the entropy model of the milling cutter to obtain the response order of the damage behavior affected by milling cutter structure and material parameters.According to the axiomatic design method,the design matrix of the function domain and the domain of the high speed milling cutter is established,and the hierarchical structure relationship of the cross scale design parameters of the milling cutter is revealed.A cross scale correlation design method for high speed milling cutter damage control is proposed,which is verified by high speed milling experiment.