Inverse electro-thermal analysis of the material removal mechanism in electrical discharge machining

Abstract

This paper shows the integrated mathematical and experimental investigation of material removal in electrical discharge machining (EDM), on the basis of electro-thermal approach. In the present model, the amount of heat energy is the equivalent to EDM’s electrical energy, so that the heat source characteristics of the discharge zone are a function of the discharge current and discharge duration. Modeling and optimization of the EDM process were conducted using the inverse heat conduction problem based on the desirable temperature distribution within a workpiece. The developed inverse model is able to determine temperature and heat flux in electrodes for the machining conditions installed during the material removal EDM process. By using the heat flux density, in contrast to previous approaches, the concept of this study enables the optimization relation between the power and duration of the heat source of a single pulse discharge. The crater dimensions at the workpiece are obtained on the basis of temperature isotherms above the melting temperature of the workpiece. The crater size enables good prediction of material removal rate and surface roughness for different EDM parameters. The inverse electro-thermal model’s predictions are compared with the experimental results.