| 摘要 |
PROBLEM TO BE SOLVED: To provide a cutting insert which has a light weight and a high binding effect when the insert is mounted, and a throwaway type cutter.SOLUTION: A cutting insert 1 is equipped with: a rake face 2 having three convex-curved long ridge lines 5 (5a, 5b, 5c) and three short ridge lines 6 (6a, 6b, 6c) alternately which are arranged point symmetrically to a center O; a seating surface 3 facing the rake face; and a lateral face having three flanks 7 extending from the respective long ridge lines 5, three step parts 8 extending to the center O side from the flanks 7, and three flat restraint faces 9 extending to the seating surface 3 side from the step parts 8. In a plan view of the cutting insert 1, distances w4, w5 from both ends x, y of a border line between the restraint faces 9 (9a, 9b, 9c) to the step parts 8 to the ling ridge lines 5 are different from each other.SELECTED DRAWING: Figure 1 |
