Computer-Aided Design for E.C.M. Electrodes

Summary

A method is described for finding tool electrode shapes from a given workpiece shape. Originally a graphical procedure was envisaged but the limited accuracy and tedium of this led naturally to the adoption of a numerical solution by digital computer with a graphical print-out. Starting from a defined equipotential workshape boundary, a model of an electric field can be constructed where each new equipotential surface is a possible tool electrode surface which will produce the original workshape. The method rests on the assumptions that Ohm’s Law applies across a small element of electrolyte and that the current flowing between a pair of flux lines in an electric field is constant. This second assumption expresses the continuity of current flow and because this is the basis for the method, the author has called it the ‘continuity’method.