Insight into fundamental aspects of the EDM process using multidischarge numerical simulation

The electrical discharge machining (EDM) process is a popular non-traditional machining process, but, although it is widely used in industry, there is still a lack of scientific knowledge about its fundamentals. This paper discusses some aspects of the discharge process at the sight of the results obtained with a previously developed thermal model, which is capable of simulating the superposition of successive discharges which leads to the formation of the “EDMed” surface. Some process characteristics such as the percentage of discharge energy transferred to the workpiece, plasma channel growth, material removal mechanism, and the influence of convective cooling are discussed in this paper, based on the information provided by the adjustments of two different EDM regimes (corresponding to roughing and finishing operations). Predictions of the extension of the recast layer and the heat-affected layer for both regimes are also addressed, and their comparison with experimental measurements shows a good agreement, which confirms the validity of the modeling tool.