Cutting insert and cutting edge replacement type cutting tool

Patent metadata

Field	Value
Publication number	US-12030128-B2
Application number	US-201917270645-A
Country	US
Kind code	B2
Filing date	Aug 27, 2019
Priority date	Aug 30, 2018
Publication date	Jul 9, 2024
Grant date	Jul 9, 2024

Abstract

A cutting insert includes first and second polygonal surfaces and a plurality of side surfaces. A corner edge that has a corner rake surface on the first polygonal surface is formed at a first corner portion, and a main cutting edge is formed from the corner edge to a second corner portion. The main cutting edge includes, at least on a corner edge side, a rake angle gradual increase region where a rake angle of a main rake surface gradually increases to a positive angle side as going from a first end portion of the corner edge toward a second corner portion side.

First claim

What is claimed is:

1. A cutting insert comprising:
a polygonal plate-shaped insert main body that includes first and second polygonal surfaces facing opposite to each other and a plurality of side surfaces which are disposed in a vicinity of the first and second polygonal surfaces,
wherein a corner edge that has a corner rake surface on the first polygonal surface exists at a first corner portion among corner portions of the first polygonal surface of the insert main body,
from the corner edge to a second corner portion adjacent to the first corner portion in a circumferential direction of the first polygonal surface, a main cutting edge that has, on the first polygonal surface, a main rake surface connected to the corner rake surface and extends from a first end portion of the corner edge, and
the main cutting edge includes, at least on a corner edge side, a rake angle gradual increase region where a rake angle of the main rake surface gradually increases as going from the first end portion of the corner edge toward a second corner portion side,
wherein the rake angle gradual increase region is within a range of 1.0 mm to 2.0 mm from the first end portion of the corner edge in plan view facing the first polygonal surface, and the rake angle of the main cutting edge is constant within a range exceeding the first end portion of the corner edge by 2.0 mm.

2. The cutting insert according to claim 1 ,
wherein the rake angle in the rake angle gradual increase region increases 5° or more.

3. The cutting insert according to claim 1 ,
wherein a boundary line between the main rake surface and the corner rake surface, which extends from the first end portion of the corner edge toward an inner side of the first polygonal surface, intersects the main cutting edge at an intersection angle within a range of 20° to 60° in plan view facing the first polygonal surface.

4. The cutting insert according to claim 1 ,
wherein the corner edge extends in a protruding direction separating away from the second polygonal surface as going toward the first end portion.

5. The cutting insert according to claim 4 ,
wherein the corner edge is formed in a concave curve shape in side view facing a corner clearance surface, which intersects the corner rake surface via the corner edge, among the plurality of side surfaces of the insert main body.

6. The cutting insert according to claim 4 ,
wherein the first end portion of the corner edge protrudes with respect to a second end portion of the corner edge on an opposite side to the first end portion by a protruding amount within a range of 0.05 mm to 0.15 mm in side view facing a corner clearance surface, which intersects the corner rake surface via the corner edge, among the plurality of side surfaces of the insert main body.

7. The cutting insert according to claim 1 ,
wherein the insert main body has an insert center line passing through centers of the first and second polygonal surfaces,
an auxiliary cutting edge is formed on the first polygonal surface to extend from a second end portion of the corner edge on an opposite side to the first end portion of the corner edge, and the auxiliary cutting edge has an auxiliary rake surface connected to the corner rake surface on an opposite side to the main rake surface, and
the auxiliary cutting edge extends along a plane perpendicular to the insert center line or toward the second polygonal surface as going away from the second end portion of the corner edge, when viewed toward an auxiliary clearance surface that intersects the auxiliary rake surface via the auxiliary cutting edge.

8. The cutting insert according to claim 7 ,
wherein an inclination angle of the auxiliary cutting edge with respect to the plane perpendicular to the insert center line in the side view facing the auxiliary clearance surface is within a range of 0° to 15°.

9. The cutting insert according to claim 1 ,
wherein on the corner edge side, the main cutting edge goes away from the second polygonal surface while forming a convex curve and then extends toward the second polygonal surface as going from the first end portion of the corner edge toward the second corner portion side in side view facing a main clearance surface, which intersects the main rake surface, among the plurality of side surfaces.

10. The cutting insert according to claim 9 ,
wherein in the side view facing the main clearance surface, a curvature radius of the convex curve formed by the main cutting edge is within a range of 3 mm to 10 mm, and the main cutting edge forms the convex curve at least within a range of 1.0 mm from the first end portion of the corner edge.

11. The cutting insert according to claim 1 ,
wherein the insert main body is formed in a hexagonal plate shape that is a rotationally symmetric shape by every 120° about an insert center line passing through centers of the first and second polygonal surfaces and is a front-back inverted symmetric shape with respect to the first and second polygonal surfaces, and
on the first and second polygonal surfaces, three first corner portions and three second corner portions are alternately disposed in a circumferential direction, and are disposed opposite to each other in a direction parallel to the insert center line.

12. The cutting insert according to claim 11 ,
wherein the plurality of side surfaces of the insert main body extend parallel to the insert center line.

13. A cutting edge replacement type cutting tool comprising the cutting insert according to claim 1 which is detachably attached to an insert attachment seat formed on a tip portion outer periphery of a tool main body having a rotation axis.

Assignees

• Mitsubishi Materials Corp

Inventors

• Kanbara Masashi
• Kitajima Jun
• SAKAMOTO Chinami
• Watanabe Shota

Classifications

• B23C2200/287

  Positive rake angles · CPC title

• B23C2200/291

  Variable rake angles · CPC title

• B23C5/202 Primary

  Plate-like cutting inserts with special form (special form related to securing of the insert B23C5/22) · CPC title

• B23C2200/203

  Curved cutting edges · CPC title

• B23C2200/0411

  irregular · CPC title