Design by functional decomposition for a high strength EDM wire electrode

A general EDM wire electrode can consist of four components. First of all the core of the wire, that is mostly responsible for tensile strength and electrical conductivity. On the core there can be an intermediate layer that gives extra conductivity to a high tensile but less conductive core. Then there is the coating which is intended to provide the wire with a high (economic) cutting speed. And fourth: on top of a wire a very thin superficial layer may be applied with variant purposes. The presence of all four or just some of these components depends on the intented use of the wire. This paper discusses the design and testing of two high tensile strength wires for EDM meant for accurate cutting, one with small diameter and one with large diameter. The design phase starts from this functional decomposition. The results clearly illustrate the benefits of a high strength wire electrode, i.e. a considerable raise in accuracy, especially in corner cutting.