Electrode drive and controls for electrochemical machining

摘要

An improved apparatus for electrolytically removing material from a workpiece includes a plurality of electrodes which are movable relative to each other through working strokes. In order to coordinate the movement of the electrodes, they are stopped at one or more predetermined intermediate positions during their working strokes. When all of the electrodes have arrived at intermediate positions, the electrodes are simultaneously moved away from their intermediate positions toward their end of stroke positions. In order to accommodate variations in the rate at which material is electrolytically removed from a workpiece, the speed of movement of the electrodes and/or the electrical potential established between the electrodes and the workpiece can be varied. Relatively large diameter rams connected with the electrodes are supplied with fluid from relatively small diameter piston and cylinder type pumps. During each electrode working stroke, the piston and cylinder type pumps are driven through a plurality of pumping strokes by reversible driving motors which are connected with the pumps by relatively short linear ball screw and nut drive arrangements. To insure that a reversal in the direction of operation of a typical screw and nut drive arrangement does not occur during the final portion of a working stroke, each of the electrodes is stopped at an intermediate position shortly before the end of its working stroke.