Investigations on hard coated reamers in different lubricant free cutting operations

Abstract The reaming finishing process sets special high demands on quality and wear resistance of used reamers. Only the best adapted cutting geometries and parametric cuts allow to obtain high surface qualities and minimum deviations from circular form. Cutting operations carried out free of cooling lubricant will cause an extreme increase in thermic and abrasive load of tools. Details given in this paper will show how, using PVD coatings, it nevertheless is possible to obtain relevant file-proven tool life results, and certainty of operation in lubricant-free reaming and lubricant-weak reaming of gray cast iron (GG25) and aluminium alloy (AlSi12). Various arc-coatings and coatings deposited by sputtering are analyzed as to their mechanical properties, and wear behaviour is compared in application. In dry reaming of gray cast iron, good tool life could be obtained, even for a high cutting speed of 100m min−1, with modified coating materials (TiAlN, TiAlCN, for instance). These are compared with other coating materials (for instance TiZrN). Cutting of AlSil2 was done successfully with TiAlN-and TiB2-coated reamers.