Multiple-cutting-edge cutter-bit and multiple-cutting-edge cutter-bit type cutting tool

Abstract

A throwaway insert (1) comprises an insert body (2) formed in a polygonal shape, a cutting face (3) formed by a polygonal face of the insert body (2), a corner cutting edge (7) which is formed in a curved shape at a corner of the cutting face (3), a major cutting edge (8) which is formed along a side edge of the cutting face (3) that is connected to a first end (7A) of the corner cutting edge (7), and a concave portion (13) which is formed, in another side edge of the cutting face (3) that is connected to a second end (7B) of the corner cutting edge (7), so as to be adjacent to the second end (7B) of the corner cutting edge (7), and so as to be made concave toward the inside of the cutting face (3) from a tangent (M) of the corner cutting edge (7) drawn at the second end (7B) of the corner cutting edge (7). By using the throwaway insert (1), cut chips are prevented from being packed in a gap between the throwaway insert (1) and a surface (V) being machined, and the fixing rigidity of the throwaway insert (1) is increased.

Description

technical field [0001] The present invention relates to a multi-edged insert (hereinafter referred to as "insert") detachably attached to a multi-edged insert type cutting tool (hereinafter referred to as "cutting tool"), and to a cutting tool to which the insert is attached. Background technique [0002] As such an insert and a cutting tool, the inventors of the present invention have proposed an insert and a cutting tool in JP-A-2000-141123. It includes a first cutting edge (main cutting edge) with a specified length, and a second cutting edge (corner edge) with a small radius of curvature that is continuous with the radial direction outside of the first cutting edge with respect to the axis of rotation. State, giving the first cutting edge a prescribed chamfer angle, the blade is detachably installed in such a way as to protrude from the outer periphery of the blade body, and the cutting tool is a kind of blade mounted thereon, by turning around the above-mentioned axis ...

AI Technical Summary

Problems solved by technology

However, in the above-mentioned insert, the side is formed in a straight line connecting the second cutting edge, so that, as described above, even if the side is formed to be inclined slightly inward in the radial direction, as the above-mentioned second cutting edge is approached, The distance between the blade side and the vertical wall will gradually narrow, so, especially in the case of processing with the above-mentioned axis as the transverse direction, the chips will bite into the narrowed space and damage the processed surface ( vertical wall) or risk of blade breakage

In addition, the blade body is formed into a polygonal plate shape, and the two adjacent side surfaces of the corner portion at the position of the diagonal line of the second cutting edge are clamped and fixed after abutting against the supporting surface of the blade body. , but since the abutment of these faces is the abutment between planes, it is difficult to ensure the installation of the insert with respect to the change in the direction of the cutting load acting on the insert, especially in the case of forming a flat part and forming a vertical wall. Rigid, there is a risk of misalignment on the blade

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