Electrochemical drilling power supply - utilising a negative DC with superimposed negative pulses connected to the electrolyte

摘要

Electrochemical drilling system which uses an insulating hollow electrode through which a highly conductive electrolyte is passed to impinge on a workpiece, has the electrolyte connected to a cathode supply consisting of a negative DC component with superimposed negative pulses. The pulses on the cathode supply provide a ripple which is 75 to 600% of the DC component and provide the sole source of drilling current, while there amplitude is insufficient to cause a spark discharge between the electrode and workpiece. Used to drill extremely small holes in tough metals such as nickel base superalloys. Conventional electrochemical drilling generally produces tapered holes and causes rapid wear of the insulating electrode. Use of pulses produces holes of more uniform dia. and reduces heat generated and the electrode wear.