US Patent 7820310 Coated cutting tool insert

A method for making a coated cutting tool insert by depositing by CVD, onto a cemented carbide, titanium based or ceramic substrate a hard layer system, having a total thickness of from about 2 to about 50 μm, comprising at least one layer selected from titanium carbide, titanium nitride, titanium carbonitride, titanium carboxide and aluminum oxide, and an outer, from about 1 to about 15 μm thick, aluminum oxide layer or (Al2O3+ZrO2)*N multilayer, a penultimate outermost layer of TiOx, where x ranges from about 1 to about 2, and an outermost, from about 0.3 to about 2 μm thick, TiCxNyOz, layer, where x+y+z=1, x≧0, y≧0, and z≧0, followed by a post-treatment removing at least said outermost layer on the edge-line and on the rake face.