Abstract
In this study, we aim to obtain the quantitative relation between debris concentration and gap width in sinking electrical discharge machining (EDM). To simulate the machining accuracy of sinking EDM, it is necessary to determine the discharge location where the dielectric breakdown strength is lowest in the gap. The discharge location is determined on the basis of the fact that the dielectric breakdown strength of the gap decreases with decreasing gap width and increasing concentration of debris particles suspended in the dielectric fluid. Hence, the relation between debris concentration and gap width was obtained. The distribution of the debris concentration in the radial direction of a circular working area was obtained by simulation, and the gap width distribution in the same direction was measured experimentally. Thus, by correlating the debris concentration with the gap width at each radial position, the relation was obtained. The gap width was expressed as an exponential function of the debris concentration whose index was lower than unity.
