Patent ID: 7500810

Claim:
A replaceable-blade cutting insert for corner milling cutters comprising: a first surface and a second surface facing opposite directions; a third surface and a fourth surface intersecting with and connecting to said first surface and said second surface; and a fifth surface and a sixth surface intersecting with said first surface and said second surface and said third surface and said fourth surface, wherein said first surface is used as a rake face, said third surface is used as an outer perimeter flank face, and said fifth surface is used as a front flank face, wherein four sections of said third surface are twisted towards said fourth surface to form four twisted surfaces that slope towards said fourth surface at substantially 3 to 15 deg, two of said four twisted surfaces of said third surface intersect with said first surface and create with said first surface a ridge line that serves as a main cutting section, and two of said four twisted surfaces of said third surface intersect with said second surface, wherein four sections of said fourth surface are twisted towards said third surface to form four twisted surfaces that slope towards said third surface at substantially 3 to 15 degrees, two of said four twisted surfaces of said fourth surface intersect with said first surface, and two of said four twisted surfaces of said fourth surface intersect with said second surface, wherein said four twisted surfaces of said third surface and said four twisted surfaces of said fourth surface are each formed with a width that gradually decreases.