Robert Boschgmbh

Oskar Sohmer

Kuno Kirner

Heinz Autenrieth

Powdered binder metal and hard metal granules are deposited in measured quantities on the cutting edge of a metal blade. When these materials both have a magnetic component, an electromagnet with an elongated air gap is used to pick up quantities determined by the amount of exciting current and to deposit them on the surface to be coated. A high-frequency heating current flows through the object being coated and also through a nearby inductor in series. This produces a short heating cycle in which the binder metal is melted, this being done in a protective gas atmosphere and without the presence of a flux. The object to be coated is held in a clamping device provided with a cavity around the surfaces to be coated, which include adjacent side surfaces as well as the edge of the blade, and the clamping plates also operate as heat sinks. The method and apparatus can also be used for sintering on a coating, but that requires a longer heating cycle.

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Stuttgart, Germany

Oskar Sohmer