The Dispersion of Arc Spots Formed by the Impulse Discharge in the EDM

This paper describes some experiments with the dispersion of the arc spots. In the EDM, it is generally known that only one crater of the arc spot at the surface of the electrode is formed due to a single transient arc discharge ignited in a liquid. In this experiment, many craters of the arc spot can be easily formed within the arc duration by the use of a certain kind of the electrode material. These many arc spots are formed by the use of the conductive material of the tool electrode with a special shape, too. The dispersion of the arc spots is caused by the occurrence of parallel arcs and the reignition arc. These unique phenomena are discussed from the point of view of the internal equivalent resistance of the tool electrode. If the dispersion of the arc spots can be applied to the EDM, it will be useful to increase in the removal rate without an increase in the surface roughness of the work. This paper introduces these phenomena into one method of improving the removal rate in the EDM.