| 摘要 |
A cutting insert is provided with a cutting part having an upper surface, a lower surface, a side surface connected to the upper surface and the lower surface, and a cutting blade located at the line of intersection between the upper surface and the side surface, the cutting blade comprises a first cutting blade which is located on the tip side of the cutting part and has an outwardly protruding arc shape when viewed from above, the upper surface comprises a breaker which has a rake surface located inside the first cutting blade and inclined downward toward the inside, and a rising surface located adjacent to the rake surface on the back end side and inclined upward toward the back end side, and when viewed from above, the breaker has, on the back end side with respect to both ends of the first cutting blade, a wide portion with a largest width in the direction orthogonal to a virtual straight line extending from the back end side to the tip side of the cutting part. |
