| 摘要 |
PROBLEM TO BE SOLVED: To solve a problem in which it is difficult to support a load with a bearing surface sufficiently when a large load is applied to a cutting insert in heavy cutting work.SOLUTION: A cutting insert comprises four side surfaces consisting of a front side surface, a rear side surface, a first lateral surface, and a second lateral surface located at a rectangular upper surface, a rectangular lower surface, and between the upper surface and lower surface. The upper surface comprises a first auxiliary cutting blade and a first main cutting blade formed in an intersection part with the first lateral side surface from the first auxiliary cutting blade toward the rear side surface. The lower surface comprises: a second auxiliary cutting blade formed in an intersection part with the front side surface; a second main cutting blade formed in an intersection part with the second lateral side surface from the second auxiliary cutting blade toward the rear side surface; a second breaker groove provided along the second auxiliary cutting blade and second main cutting blade; and a flat second contact surface located at the inner side of the second breaker groove. The second contact surface extends up to a region close to the front side surface in an intersection part of the lower surface and first lateral side surface. |
