| 摘要 |
<p>A cutting insert includes a through hole passing through oppositely facing upper and lower faces which have dissimilar structures, and are connected by a plurality of side faces. The upper face has 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. The lower face has 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.</p> |
