| 摘要 |
PROBLEM TO BE SOLVED: To prevent a cutting blade length of a main cutting edge from being shortened even if a radius of a corner blade is increased between cutting inserts having equal external dimension, and prevent a cutting resistance from being increased and a cutting blade strength from being lowered while securing the clearance angle of the corner blade.SOLUTION: A cutting insert includes a square plate-like insert body 1 having two each of square surface 2, end surface 3 and side surface 4, and formed in 180° rotational symmetry around an insert central line L1. A main cutting edge 5 gradually projecting as going to two corner sides positioned on one diagonal line of the square surface 2 is formed in the side edge part intersecting with the square surface 2 of the end surface 3. An intersecting edge line part 6 between the square surface 2 and the side surface 4 is formed in a convex surface to intersect with the end surface 3, and thereby a convex curve-shaped corner blade 7 ranging to the main cutting edge 5 is formed in the corner C of the end surface 3 positioned in the two corner sides of the square surface 2. The convex surface formed by the intersecting edge line part 6 is formed such that a curvature radius is gradually reduced as being spaced apart from the corner blade 7.SELECTED DRAWING: Figure 1 |
