A Computer Integrated Machining Strategy for Planetary EDM

In order to optimize planetary EDM, an appropriate machining strategy was defined and implemented using a micro computer. The strategy calculates and adapts on-line the pulse current and the discharge duration based on a continuous measurement of the eccentricity. A number of independent sectors on the planetary orbit were defined. The generator settings that are to be applied in a sector are calculated one turn of the planetary orbit in advance. A machining time gain of about 50% could be observed for a cylindrical electrode. Alternative planetary motions are investigated to overcome some specific problems related to the circular planetary motion. It is proposed to combine the circular orbit with a lateral uni-directional machining mode in function of an on-line form recognition of the planetary orbit. This planetary motion is introduced in the machining strategy, yielding an additional time gain of about 30% for a rectangular electrode