Electrical discharge machining apparatus with discharge current control

摘要

A discharge machining apparatus adapted to permit the supply of discharge current to be cut off without increasing electrode consumption. Arrangements are made to gradually increase the level of discharge current, rather than maintaining the current level of discharge pulse. By doing so, electrode consumption becomes independent of the pulse width of the discharge pulse, so the discharge current can be cut off immediately after an abnormal state such as short circuiting or an instantaneous interruption of the discharge current occurs, eliminating the danger of deteriorating the quality of the machining surface of a workpiece.