Method of operating electrochemical machine tool

摘要

Multiple hole drilling by the electro-chemical process, in which individual jets of electrolyte impinge upon a workpiece, presents problems in assessment of hole depth reached and/or of jet deflection through jet orifice blockage. The invention provides a device which looks for the corona at the head of each jet. If the corona is present, the device generates and electrical signal which inhibits the actuation of a further device the function of which is to remove the jet, the corona of which has extinguished. Device also senses the displacement of the corona from a datum and in response, initiates switch off the machine tool.