| 摘要 |
<p>A cutting insert (10) according to an aspect of the present invention is provided with a plurality of cutting portions (18) formed at the intersection portion of each end surface (12, 14) and a peripheral surface (16). Each cutting portion includes a first cutting edge (18a) and a second cutting edge (18b). In an end surface view, first corners (20) and second corners (22) which differ in their internal angles are alternately formed in each end surface. An internal angle ± of the first corner (20) is smaller than an internal angle ² of the second corner (22, 122, 222). Each first cutting edge (18a) has a portion extending to approach the median plane M as a distance from a corresponding first corner (20) increases. A first side surface portion (30a) extending on the peripheral surface from each first cutting edge forms an insert internal obtuse angle to a plane passing through the first cutting edge and being in parallel to the median plane M, and a second side surface portion (30b) extending on the peripheral surface from each second cutting edge forms an insert internal acute angle to a plane passing through the second cutting edge and being in parallel to the median plane M.</p> |
