Research On Machinability In High Speed Milling

The process of high speed milling is very complicated,and the existing scientific research is still unable to give a comprehensive explanation of the special phenomena in the process of high speed milling.Therefore,we need to understand the machinability in high speed milling.This paper carried out the research of high speed milling of 3Cr2 Mo steel and 45 hardened steel,provide a theoretical basis for further improving the processing efficiency and quality.In this thesis,the cutting machinability in high speed milling is studied by means of experimental observation,theoretical analysis and modeling.In this thesis,the whole cylindrical end milling cutter with TiAlN coating and TiAlN coated carbide ball milling cutter are selected,and the milling tests are carried out in the range of 270~945m/min.The main contents and results of this study are as follows:(1)High speed milling experiments of 3Cr2 Mo steel and 45 hardened steel,and milling conditions on chip morphology and deformation analyses.The test results are as follows:(1)With the increase of milling speed,the shape of chip gradually appears as zigzag,and when the speed of milling reaches critical value,adiabatic shear deformation occurs.(2)For workpiece materials with higher hardness,the sawtooth degree of chip is relatively high,and the milling speed needed to form such chips is low.(2)The advantages and disadvantages of JC model and power exponent model were analyzed comprehensively.A new material dynamic mechanical model for 3Cr2 Mo steel was established by ABAQUS software.The simulation results are basically consistent with the actual test results.(3)The influence of milling speed on milling force and its dynamic characteristics is analyzed by high-speed milling test.The conclusions are as follows:(1)At the initial stage,milling force increases with milling speed increasing,but when milling speed exceeds critical value,milling force decreases with milling speed increasing.(2)In high speed milling,the milling force waveform is different from the conventional milling force waveform,and it has signal output in the cutting and non cutting areas.(3)The milling force in frequency domain appears only at the multiple times of the fundamental frequency.When the dominant frequency of the dominant frequency is the same as that of the cutter tooth,the harmonic vibration is generated.