Electric discharge machining electrode and method

The EDM method for finishing operations on a workpiece comprising the steps of:

• providing a replica of the workpiece;
• and
• molding a ductile electrode in the replica of the workpiece.

An EDM method for finishing operation on a milled metal cavity using the pre-milled cavity as a mold to form a negative replicate of the cavity onto a ductile electrode that results as a negative of the milled metal cavity so that micro-groove valleys of the milled metal cavity become micro-peeks of the electrode that level the milled metal cavity surface by spark erosion and, once a prescribed fraction of the cavity surface roughness is flattened and a new, smoother, cavity surface is obtained, the electrode is reprocessed in the new, smoother, cavity in order to match the surface thereof with the new, smoother, cavity surface.

A method for molding a composite carbonaceous material into a generic electrode of simple geometric shape held around a metallic insert holder wherein a ductile electrode material is softened to yield a softened electrode, which is then pressed against a mold in order to be given a final shape and surface finish.

The method recited in 38, wherein the ductile electrode material is softened by a method selected in the group comprising induction heating, radiant heating and conduction heating.

The method recited in 38, wherein the softened electrode is pressed against an original of a part of a workpiece in order to extract a negative geometry thereof, which can be used to duplicate an original geometry of said part.

The method recited in 38, wherein the softened electrode is carved by a relative movement between the softened electrode and the mold, following 3D trajectories.

The method recited in 38, wherein the softened electrode is pressed by inflating a hollow electrode, held by a bored metallic insert, inside a multiple parts mold which temperature can be controlled by cooling passages.

A use of a ductile carbonaceous-metal polymer composite material as an EDM electrode to perform electric discharge machining of electrically conductive material.

A method for finishing and polishing a workpiece using a ductile electrode material, by following a pressing method where the ductile electrode is a replica of the workpiece or of a part of the workpiece that is used to remove micro-peeks by EDM machining, by shifting the electrode from an initial molding position thereof over a width of the micro-peeks.