Research On Mechanical Behavior In Ultra-Precision Machining

Some machining phenomenas in the developed ultra-precision machining cannot be explained by traditional cutting theory.Existing cutting theory cannot fully consider the non-uniform force of the material and the elastic recovery of the processed material.The laws of traditional cutting theory cannot be used in ultra-precision cutting.On the premise of comprehensive analysis of the deformation of ultra-precision cutting materials and the distribution of tool forces,a new theoretical model of cutting force prediction for ultra-precision machining is established.The model obtains the distribution law of strain energy per unit volume in different regions and the size of the strain region by considering the stress distribution characteristics of different cutting deformation regions,so as to calculate the material strain energy and cutting force more accurately.In this paper,the main research contents are analytical modeling of ultra-precision cutting forces,finite element simulation analysis,and verification of test results during the cutting process.The research is carried out from the following three aspects.Firstly,by studying the source of cutting force,an analytical model of ultra-precision cutting force is established.The first source of the cutting force is that the tool in the chip shear deformation zone generates shear strain energy in the direction of the shear angle during the cutting process.The second source of the cutting force is the energy of the tool-chip friction zone is mainly the relative slip between the chip and the tool surface.The internal frictional energy generated by the shift and the tensile and compressive strain and shear strain generated by the chip surface due to the positive pressure and friction force.The third source of the cutting force is the compressive strain energy and shear strain energyy of the tool's blunt radius.By integrating the strain energy per unit volume in the strain zone,the strain energy in different deformation zones is obtained.Through the theoretical calculation of the cutting force,a relatively general calculation formula is obtained,which is suitable for the theoretical study of cutting force.Secondly,using ABAQUS cutting simulation software and modeling based on Johnson-Cook constitutive model and ALE adaptive grid.,finite element simulation of copper and aluminum materials was carried out.And the influence of the cutting thickness,cutting speed,tool blunt radius and tool rake angle on cutting force were studied.Analysis of the cutting simulation results shows that the calculation method for calculating the cutting force according to the strain energy of the cutting material can accurately obtain the ultra-precision cutting force At the same time,it can be found that among the four cutting parameters,the factors that have the greatest impact on the cutting force are the cutting thickness and the front of the tool angle.Finally,using the experimental data of the cutting force of different materials in the existing literature,the cutting force under the same cutting conditions is obtained through the theoretical calculation method,and the calculated and measured values of the cutting force at different cutting thicknesses and cutting speeds.The comparative analysis shows that the error between the calculation result of the model and the test result is small,and it can predict the cutting force of various metal materials.