Patent ID: 8875393

Claim:
A method of forming a cooling channel in a wall presenting an inside surface and an outside surface suitable for being cooled by cool air flowing in said channel, the channel comprising a hole and a diffusion portion, the hole opening out at a first end into the inside surface, and at a second end into the diffusion portion presenting an orifice, the diffusion portion flaring around said orifice and opening out into the outside surface, the method comprising: piercing the wall to make said hole; and forming an indentation in the outside surface of the wall to form said diffusion portion by using an electroerosion electrode, wherein said electrode comprises a tip which is in the form of a cone having a cone end, a conical surface, and a cone axis, the cone end being rounded and the conical surface including a flat extending on one side of the cone from a point in a vicinity of the cone end beyond a portion of the cone having a maximum flare of the cone, the flat not intersecting the cone axis and not intersecting the cone end, and wherein the flat faces the outside surface of the wall while forming the indentation.