Method and apparatus for electrochemical machining including servo means sensitive to a phase shift in an lc circuit for controlling the machining

Claim 1

IN THE PROCESS OF ELECTRICALLY REMOVING STOCK FROM A CONDUCTIVE WORKPIECE BY A CONDUCTIVE ELECTRODE, THE STEPS INCLUDING MANEUVERING THE WORKPIECE AND THE ELECTRODE RELATIVE TO EACH OTHER SO AS TO FORM A PREDETERMINED GAP THEREBETWEEN, FLOWING ELECTROLYTE TO THE GAP, APPLYING ELECTRICAL ENERGY ACORSS THE GAP SO AS TO EFFECT STOCK REMOVAL FROM THE WORKPIECE, APPLYING A.C. ELECTRICAL ENERGY TO AN LC SERIES CIRCUIT INCORPORATING A PREDETERMINED INDUCTIVE REACTANCE ARRANGED IN SERIES WITH THE GAP, WHICH CONSTITUTES THE CAPACITIVE REACTANCE, SO THAT CHANGES IN THE GAP SPACING FROM THE PREDETERMINED GAP CAUSE CORRESPONDING CHANGES IN THE LC CIRCUIT IMPEDANCE, DETECTING THE IMPEDANCE CHANGES, AND ALTERNATING THE MANEUVERING OF THE WORKPIECE AND THE ELECTRODE RELATIVE TO EACH OTHER IN RESPONSE TO THE ELECTRICAL QUANTITY SO AS TO MAINTAIN THE PREDETERMINED GAP.