Patent ID: 8142621

Claim:
A method of making a cutting insert, comprising a cemented carbide substrate and a coating, said cemented carbide substrate comprising about 5 wt % to about 7 wt % Co; about 0.05 wt % to about 2.0 wt % metals selected from the group consisting of Ti, Nb, Ta, and combinations thereof; and balance WC; wherein said substrate has a coercivity (Hc) of about 14 kA/m to about 19 kA/m and an S-value of about 0.81 and about 0.96; said method comprising: depositing a coating comprising: a homogeneous layer of (TixAh-x)N; wherein x is between about 0.25 and about 0.50; wherein said homogeneous layer of (Ti x Al 1-x )N has a crystal structure of NaCl symmetry and a total thickness of between about 1.0 11 m and about 5.0 11 m, as measured on a middle of a face; via arc evaporation of an alloyed cathode or a composite cathode, wherein said alloyed or composite cathode composition comprises about 25 at. % to 50 at. % Ti, at an evaporation current of between about 50 A and about 200 A depending on cathode size and cathode material having a substrate bias of between about −20 V and about −35 V and a temperature of between about 400° C. and about 700° C., in an Ar+N 2 atmosphere comprising about 0 vol. % to about 50 vol. % Ar, at a total pressure of about 1.0 Pa to about 7.0 Pa.