Sandvik Ab

Hans Johansson

Ulf Rolander

Peter Littecke

Anders Nordgren

The present invention discloses an HSS tool with a PVD coating and with at least one cutting edge. The cutting edge has a radius of 15-25 &mgr;m and the carbides in the HSS are in contact with the coating. The present invention also relates to a method of making an HSS tool provided with a PVD coating with improved wear resistance. The improvement is obtained by subjecting the tool prior to the deposition of the coating to an electropolishing treatment such that a cutting edge radius of 15-25 &mgr;m is obtained and that the carbides in the HSS are revealed.

Method of making a PVD-coated HSS drill

The present invention relates to a method for polishing coated cutting tools and wear parts, where at least the outer layer of the coating consists of TiN, TiC or Ti(C,N), to a high surface finish. An electrolytic method is used with an electrolyte consisting of perchloric (HClO.sub.4) or sulphuric (H.sub.2 SO.sub.4) acid, 2-50 volume %, in methanol or other organic liquid. The method is easier to control than conventional mechanical methods and renders a high surface finish over the whole coated part.

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Stockholm, Sweden

Hans Johansson