Abstract: An improved electrode for producing cone-shaped diffusion openings in the wall of an air-cooled rotor blade of a jet engine or other gas turbine by means of electro-discharge-machining (EDM), is described. The electrode has a needle-like forward end section for forming a round air metering hole, and a cone-like head section which permits the formation of a cone-shaped diffusion opening. The hole and the diffusion opening are formed with a single electrode in one operation. Also described is the method of forming such an electrode by a coining step.

Abstract: An improved electrode for producing cone-shaped diffusion openings in the wall of an air-cooled rotor blade of a jet engine or other gas turbine by means of electro-discharge-machining (EDM), is described. The electrode has a needle-like forward end section for forming a round air metering hole, and a cone-like head section which permits the formation of a cone-shaped diffusion opening. The hole and the diffusion opening are formed with a single electrode in one operation. Also described is the method of forming such an electrode by a coining step.