Patent ID: 8585331

Claim:
A cutting insert comprising an upper face and a lower face opposite to each other, a plurality of side faces connecting the upper face and the lower face, and a through-hole passing through the upper face and the lower face; wherein: the upper face and lower face are non-identical cutting faces having dissimilar structures; the upper face comprises an upper cutting edge formed on the outer periphery thereof, a flat land at the highest level disposed adjacent to and along the upper cutting edge, and a groove region at a level lower than that of the upper cutting edge and disposed between the flat land and the through-hole; and the lower face comprises chip breakers formed on parts of peripheral regions which include each of the corners made by adjacent side faces, lower cutting edges formed on the outer periphery of the lower face along the chip breakers, and a flat supporting surface formed on the peripheral regions between adjacent chip breakers and continuously on regions inward of the chip breakers.