Electrode for electrical discharge machining

In combination with an EDM apparatus, a filament electrode for electrical discharge machining of a workpiece wherein said filament electrode is displaced longitudinally and laterally through the workpiece, said filament electrode comprising a core made of material having a relatively high mechanical strength and a relatively thin metallic surface coating on said core, said metallic surface coating comprising at least 50% of a metal having a low temperature of vaporization selected from the group consisting of zinc, cadmium, tin, lead, antimony, bismuth and an alloy thereof, wherein the core of said filament electrode is metallic and is selected from the group consisting of copper, brass and steel.

A process for EDM machining, said process comprising electroplating on a metallic filament a relatively thin surface coating containing at least 50% of a metal having a low temperature of vaporization selected from the group consisting of zinc, cadmium, tin, lead, antimony, bismuth, and an alloy thereof by passing said metallic filament through an electrolytic bath for plating said metallic filament with said surface coating, and subsequently passing said coated filament through the machining zone of an EDM apparatus.

A process for the manufacture of a wire electrode for electrical discharge machining comprising passing a metallic wire through an electroplating bath for electroplating on said metallic wire a surface coating containing at least 50% of a metal selected from the group consisting of zinc, cadmium, tin, lead, antimony, bismuth and an alloy thereof, wherein said electroplating is effected in an EDM apparatus by passing said wire through said electroplating bath before passing said wire through a machining zone between said wire and a workpiece.

An EDM apparatus comprising a wire electrode, a workpiece-electrode, means for passing the wire electrode through an electroplating bath for forming a surface coating on said wire electrode containing at least 50% of a metal selected from the group consisting of zinc, cadmium, tin, lead, antimony, bismuth and an alloy thereof, means for guiding said electroplated wire electrode through a machining zone between said wire electrode and the workpiece electrode and means for feeding said wire electrode after passing through the machining zone through said electroplating bath for replating on said wire electrode surface coating removed in the course of passage through the machining zone.

An EDM apparatus comprising a wire electrode, a workpiece-electrode, means for passing the wire electrode through an electroplating bath for forming a surface coating on said wire electrode containing at least 50% of a metal selected from the group consisting of zinc, cadmium, tin, lead, antimony, bismuth and an alloy thereof, means for guiding said electroplated wire electrode through a machining zone between said wire electrode and the workpiece electrode, means for feeding said wire electrode after passage through the machining zone through said electroplating bath for replating on said wire electrode surface coating removed in the course of passage through the machining zone, and means for sizing said wire electrode after passage through said electroplating bath and before passage through said machining zone.