Applications for the aerospace industry

ECM-processing of bent elliptical coolant channels for turbine disks

ECM-technology demonstrates its true value in the production of critical parts for the aerospace industry. Köppern uses this process to manufacture highest quality bent, elliptical coolant channels for high-pressure turbine disks (HPT) for Rolls Royce in Germany. These represent an especially critical and stress-prone aero-engine component that has to be completely crack-free, with a streamlined in- and outflow combination of the coolant channel. ECM-processing offers the only possibility of fulfilling these preconditions in relation to high-strength working materials that are difficult to machine. In production, the size of the 74 coolant channels on a disk is accurately maintained at +/- 0.05 mm.

ECM processing of aero-engine cowlings

The machining of cowling parts for modern aero-engines by way of ECM is fundamentally unproblematic and does not depend on the size of the component, even when using high-strength materials. This example shows the result of machining a complex geometry with a rectangular opening 12 times along the 1.2m circumference of a conical ring in a single operation. In addition to the streamlined rounded forms, the depth of the wing-shaped pockets, with a remaining material layer of only 1.5 mm thickness, is worthy of note. The unique construction of the ECM tool allows the geometry to be produced without any washing-out grooves on the surface.

A similar product was manufactured by Köppern in 1985 for a French customer. Despite a comparable thickness of 1.5 mm, one still had to employ a concept that created washing-out grooves. Subsequent experience and the continuous advancement of ECM-technology have now made it possible to avoid these grooves, which would otherwise have to be polished away at extra expense.