Study On Vibration Assisted Diamond Cutting Proess Of Pure Iron

Pure iron materials have excellent plasticity,impact toughness and electromagnetic properties,which are widely used in the manufacturing of key components in aviation instruments,accelerators and other products.Such parts are generally in high temperature,high pressure and other extremely complex special environment.Therefore,more stringent requirements are put forward for the machining accuracy and performance of the parts,which not only require high dimensional accuracy,shape and position accuracy,but also put forward higher requirements for surface physical and mechanical properties such as work hardening and residual stress.However,due to its poor rigidity,the surface deformation is serious in the process of machining,and it is easily deformed by the initial stress,machining residual stress,cutting force,cutting heat and other factors,which affects the machining accuracy of the parts.Compared with the traditional cutting method,the ultrasonic vibration assisted cutting method can effectively reduce the cutting force and the heat generated by cutting,and prolong the tool life due to the processing characteristics of the intermittent contact between the tool and the workpiece.Therefore,it is of great significance to carry out the basic theoretical research on the diamond machining process of pure iron materials,study the vibration assisted cutting process and clarify the influence of process parameters on the surface morphology of workpieces around the precision machining of pure iron parts.In this paper,the orthogonal cutting process of diamond assisted by pure iron vibration is taken as the research object.Through the combination of finite element simulation and cutting experiment,the specific research contents are as follows :The basic theory of pure iron vibration assisted diamond cutting is studied.According to the need of solving calculation,the display solver is selected to model the temperature-displacement coupling.According to the material mechanical properties of pure iron metal,the Johnson-Cook constitutive model is selected to simulate the strain state in the machining process.The chip failure criterion based on fracture energy is adopted to prevent the influence of mesh size on the unit failure.In order to solve the problem of CPU performance limitation,the mass scaling technology is used,which greatly improves the simulation calculation efficiency.Based on the relationship between duty ratio and cutting speed in the vibration cutting process,the influence of speed on the contact rate between tool and chip in a single vibration period is obtained.The vibration assisted cutting principle is studied,and the harmonic vibration module is added to the ABAQUS finite element model to realize the vibration assisted cutting process analysis of the tool.The finite element simulation of the influence of process parameters on the cutting force,surface residual stress and surface roughness in the vibration assisted diamond cutting of pure iron was carried out.The stress field distribution,cutting force,surface roughness and residual stress distribution of machined workpiece in the process of pure iron vibration assisted diamond cutting are systematically studied.The validity of the finite element simulation model is verified by comparing the simulation with the actual theoretical process.Through the analysis of the established vibration model,the effects of cutting speed,cutting depth,tool rake angle,vibration amplitude and vibration frequency on the surface characteristics of the workpiece after cutting are studied.Experimental study on pure iron vibration assisted diamond cutting process was carried out.The experiments of variable cutting speed and cutting depth were carried out on the ultra-precision lathe.The surface roughness of the machined pure iron was detected by white light,and the chip morphology was observed by SEM electron microscope.The effects of cutting speed and depth on the surface characteristics of the machined pure iron workpiece were analyzed.The simulation results were compared with the experimental results by single factor control variable method,and the influence of cutting parameters on the surface characteristics of pure iron was obtained.