| 摘要 |
A cutting insert capable of suppressing shifting of the cutting insert during cutting is provided. A cutting insert having first and second end surfaces and a peripheral side surface comprises: a cutting edge which includes at least one circular-arc-shaped cutting edge; and a contact surface portion formed in the second end surface. When a reference axis A is defined as a line passing through the center of the first end surface and being perpendicular to the first end surface, and when a virtual circle is defined so that the virtual circle includes, as its arc, a first circular-arc-shaped cutting edge in a plan view, the center E of the virtual circle is apart from the reference axis A. When a first reference plane B is defined as a plane including the reference axis A and extending through the center of the virtual circle; a second reference plane C is defined as a plane extending perpendicularly to the reference axis A; and a virtual plane D is defined as a plane orthogonal to both the first reference plane B and the second reference plane C and extending so as to intersect with the first circular-arc-shaped cutting edge and traverse the contact surface portion, the contact surface portion has, in the virtual plane D, an inclined portion which gradually becomes more distant from the second reference plane C heading from one end to the other. |
