Research on the energy distribution of micro EDM by utilization of electro-thermal model

In electrical discharge machining (EDM), material is heated to an extremely high temperature then moved by melting and vaporization. Understanding the energy distribution and heat transfer during the process is conducive to knowing more about the machining mechanism of EDM. Many researches have been conducted to explore the energy distribution in micro EDM. Almost all of these efforts did not consider the difference in material removal mechanism between conventional and micro EDM, which has severe effects on the accuracy of their research. This paper proposes a method in regard to micro EDM for estimating plasma radius and energy distribution through comparing the results of experiment and theoretical calculation. In this method, the differences in the material removal mechanism between conventional and micro EDM are properly considered. The results of single discharge experiment were analyzed by this method. The plasma radius and fraction of energy transferred into workpiece are determined by the discharge current and discharge duration. The increase of discharge current and discharge duration led to the increase of plasma radius, while low discharge current and high discharge duration is helpful for improving the fraction of energy transferred into workpiece.