| 摘要 |
PROBLEM TO BE SOLVED: To provide a cutting insert that even in the cutting work of hot rolled soft iron or cold rolled plates and the like, chips are securely hit the projection of a braker to provide a good chip dischargeability for curling and stably discharging chips. SOLUTION: In the end part of a nose part 4 in which a braker projection 8 is formed in the central part of a braker groove 6, the braker groove 6 is made to be shallow and wide in breadth, and to have a smaller rake angle from the cutting edge, and further the cutting edge 3 is made to be descended downward at a prescribed angle to both sides from the cutting edge end 5 of the nose part 4. In other words, the difference E in level between the cutting edge end 5 of the nose part 4 and the braker groove 6 is made to be 0.01 to 0.1 mm, the distance F from the cutting edge end 5 to the rising start point of the braker projection 8 is made 0.3 to 0.7 mm, the rake angleαranging from the cutting edge end 5 to the braker groove 6 is made 2 deg. to 13 deg., and the descending angleβof the cutting edge 3 from the cutting edge end 5 is made to be 4 deg. to 8 deg..
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