Abstract:
A method of electrical discharge machining a workpiece, while maintaining the desired size, shape and surface finish of the cut. After an initial machining operation at an initial power setting forms a cut of the desired size and finish in the workpiece to some initial depth, a multi-phase machining cycle is established to carry the cut deeper. Machining is carried out for most of this multi-phase cycle at a reduced power setting, which results in the reduction of at least the rate of particulate debris production. If reduced on-time power settings are employed, the average particle size of the debris is also reduced. At the very end of the multi-phase machining cycle, the power setting is abruptly increased to a level which is sufficient to cause substantial agitation of the dielectric fluid in the spark gap. If the on-time power level has been reduced, the cut is enlarged to the desired size by the terminal power pulse. Hydraulic flushing by physically stroking the electrode in and out of the spark gap may also be employed, if desired.