CUTTING INSERT AND CUTTING TOOL

摘要

A cutting insert having a cutting edge capable of suppressing an increase in cutting resistance applied to a cutting boundary portion with an increase in a depth of cut is provided. The cutting insert has a rake face, a flank, and a cutting edge formed at an intersection portion between the rake face and the flank and is removably attached to a mounting seat. The cutting edge has an angle decreasing portion in which a cutting edge angle gradually decreases in a direction in which the depth of cut of the cutting edge increases. For example, the rake face includes an upper rake face and a lower rake face. The flank is formed on a side surface between the top and bottom surfaces. The cutting edge is formed at an intersection portion between the upper rake face and the flank.