Simulation And Experimental Study On Forming Process Of Surface Remelt Layer In EDM

In the process of EDM,when the workpiece absorbs heat under the influence of instantaneous heat source,the material on the workpiece surface melts and vaporizes instantaneously,resulting in a remelting layer of melting and solidification on the workpiece surface.The existence of remelting layer and internal cracks in remelting layer will adversely affect the working performance of the workpiece.Therefore,the simulation research on the size and morphology of single pulse EDM discharge pits and remelting layer is carried out,and on this basis,the numerical simulation and experimental research on the workpiece surface roughness and remelting layer thickness after continuous pulse EDM are carried out,which is conducive to revealing the influence of peak current and pulse width on the remelting layer thickness and surface roughness.The study of the relationship between the thickness of remelted layer and the surface roughness is of great significance for predicting the thickness of remelted layer by the surface roughness.Firstly,a simulation model of the temperature field during EDM single pulse discharge process was established to simulate the temperature distribution on the workpiece surface under EDM single pulse discharge,and to analyze the influence of pulse width and peak current on the maximum temperature,corrosion size and remelting layer thickness.Then,on the basis of the simulation of the temperature field during EDM single pulse discharge process,the simulation model of the temperature field during EDM continuous pulse discharge process was established,and the temperature distribution and surface topography of the workpiece surface under EDM continuous pulse discharge were simulated numerically.The effects of pulse width and peak current on surface morphology,surface roughness and thickness of remelted layer during EDM continuous pulse discharge were analyzed.Finally,the EDM experiments under different peak current and pulse width conditions are carried out based on the central composite design method.The influence of peak current and pulse width on surface roughness and thickness of remelted layer was analyzed.Verify the accuracy of the temperature field simulation model of the continuous pulse EDM process.