| 摘要 |
PROBLEM TO BE SOLVED: To provide a cutting insert having high hardness of a cutting edge, and hardly accumulating heat in the cutting edge.SOLUTION: A cutting insert 10 includes: an upper protrusion flank 42 where a shape of a top face 20 is a parallelogram shape in which outward curved short side and long side are connected at a corner, and a flank of a cutting edge 22 at a short side is adjacently formed in the cutting edge 22; a lower flank 41 connected to an undersurface 30; and a connection surface 43 connecting both of them. The top face includes one or a plurality of cutting faces, and a central flat surface 60 in parallel to the undersurface, and a border line N between the cutting surface and the central flat surface 60 has a curved part recessed toward the center part of the top face. A midship part M of the curved part is shifted only by a length of 15% of a width W of the cutting insert 10 to the right and left, about a center of a most protruded part 22c of the cutting edge at a short side, and is in an area sandwiched between two virtual lines in parallel to the long side.SELECTED DRAWING: Figure 1 |
