Study On Finite Element Simulation And Experiment Of WEDM In Gas

Cr12MoV has good abrasion resistance and corrosion resistance after quenching process.It also has high hardness.Through traditional method,it is difficult to carry on the processing,and tool is damaged severely.In order to reduce tool damage and obtain a good surface quality,Cr12MoV is processed by WEDM in gas.Compared with WEDM in liquid,it is not easy to give off harmful gases and produce decomposed substances,and it also has good molding characteristics.However,due to the limitation of existing experimental conditions,WEDM in gas is still in the theory and experimental research stage.Through the study of processing mechanism of WEDM in gas,this paper set up the heat transfer model of moving single pulse discharge in WEDM.The initial and boundary conditions of the temperature field and stress field were set,meanwhile,the heat conduction equation,elastic and plastic constitutive equations,and the thermal stress and strain relation equations were solved.Based on the finite element theory,finite element simulation models of WEDM in gas were established by the finite element analysis software ABAQUS,which revealed surface heat transfer evolution rule of Cr12MoV,also revealed the distribution and change rule of temperature field,stress and strain field in the manufacturing process.And the electric erosion pit morphologies with heat sources under different conditions were analyzed.Under dynamic condition,geometric model of a single electrical corrosion pit was half of the double ellipsoid.According to actual processing condition,the geometry model of a single electric erosion pit was revised.The volume calculation of revised electrical erosion pit was processed,then the influences on the electric erosion pit geometry morphology by the peak current,pulse width and wire walking speed were discussed.On the basis of theoretical research and simulation analysis,this paper formulated many processing experiment programs of WEDM in gas.Cr12MoV was processed by wire cutting processing,and surface morphologies of workpiece of WEDM in gas and liquid were analyzed.Through single factor method,material removal rate and surface quality of workpiece were obtained under different process parameters such as the peak current,pulse width,the offset and the workbench feed speed.After the simulation data and real data were compared,the error was in theallowed range,and the rationality of the model was verified.Through the finite element simulation analysis,the surface geometry morphology of discharge pit and its influencing factors are effective,which has great significance on the prediction of processing speed and surface quality.