Erosion prevention and fault detection for electrochemical machining apparatus

摘要

Destructive erosion of the tips of cathodes used in electrochemical machining operations, which is due to reverse current flow through the workpiece and cathode during nonmachining operations, is prevented by continuously passing a small DC current through the workpiece and cathode in the same direction as the normal current flow during machining operations. The voltage drop produced by the current flow may also be used to indicate the occurrence of a fault such as a lower than normal gap resistance between the cathode and workpiece during non-machining operations and thereby prevent actuation of the main power supply until the fault is corrected.