Multiple electrode electrical discharge machining

摘要

Electrical discharge machining apparatus in which a plurality of generally parallel electrodes are moved during machining and during refeed in generally parallel paths. A drive roller assembly is provided for refeeding the electrodes after each machining cycle to compensate for erosion of the electrodes that occurred during the preceding machining cycle. The drive roller assembly consists of a plurality of rollers arranged on opposite sides of the electrodes so that the electrodes are drivingly engaged between the rollers. In one embodiment of the invention, the rollers slip on the electrodes after the electrodes have been moved to positions engaging the work until all of the electrodes have been moved into engagement with the work. In another embodiment of the invention, each electrode is independently driven and engagement of each electrode with the work is electrically sensed and in response to such sensing, the drive for that electrode is discontinued. In all cases, the drive roller assembly for refeeding the electrodes is deactivated during machining and the electrodes are firmly clamped against the carriage on which the drive roller assembly is supported.