Patent ID: 8097332

Claim:
An indexable cutting insert comprising a base and a coating layer, wherein the base includes at least one flank face and at least one rake face, the flank face is connected to the rake face with an edge line provided therebetween, the coating layer includes an inner sublayer having one or more subsublayers and an outer sublayer formed on the inner sublayer, each of the subsublayers constituting the inner sublayer is composed of a compound containing at least one element selected from the group consisting of Group IVa elements, Group Va elements, Group VIa elements in the periodic table, Al, and Si, and at least one element selected from the group consisting of carbon, nitrogen, oxygen, and boron, the outer sublayer is an alumina sublayer or a sublayer containing aluminum, and in portions of the outer sublayer configured to participate in cutting, when an average thickness on the flank face side is represented by A μm and an average thickness on the rake face side is represented by B μm, A/B≦0.95, wherein of the outer sublayer configured to participate in cutting has a compressive stress, and wherein the inner sublayer and the outer sublayer excluding the outer sublayer configured to participate in cutting have a tensile stress.