Provided is a cutting insert that can suppress damage of a corner cutting edge. The cutting insert has an approximately polygonal shape, and is constituted of a main cutting edge and a corner cutting edge connected to the main cutting edge. The cutting insert includes: a first side face portion that is connected to the main cutting edge, has a negative clearance angle, and is formed such that height thereof increases gradually in a direction of approaching the corner cutting edge; and a second side face portion that is connected to the corner cutting edge, has a negative clearance angle, and has height that is greater than the first side face portion.

Provided is a cutting insert that can suppress damage of a corner cutting edge. The cutting insert has an approximately polygonal shape, and is constituted of a main cutting edge and a corner cutting edge connected to the main cutting edge. The cutting insert includes: a first side face portion that is connected to the main cutting edge, has a negative clearance angle, and is formed such that height thereof increases gradually in a direction of approaching the corner cutting edge; and a second side face portion that is connected to the corner cutting edge, has a negative clearance angle, and has height that is greater than the first side face portion.

A cutting insert 2 comprises a peripheral side surface 30 which is parallel to a central axis O of a first end surface 10 and a second end surface 20. The peripheral side surface 30 comprises a first side surface 31 facing a first major cutting edge 11, a second side surface 32 facing a first wiper edge 12, and a third side surface 33 facing a first inner edge 13. A flank 311 of the first major cutting edge 11 and a flank 321 of the first wiper edge 12 are inclined such that the flank 311 and 321 approaches the central axis O as it heads toward the first end surface 10. The flank 311 of the first major cutting edge 11 is located on a different plane from the first side surface 31. The flank 321 of the first wiper edge 12 is located on a different plane from the second side surface 32. Meanwhile, a flank of the first inner edge 13 is located on the same plane as the third side surface 33.

A cutting insert has a plate shape centered on an insert center axis. The cutting insert includes a front surface and a back surface facing an insert axial direction, an outer peripheral surface facing outward in an insert radial direction, and a cutting edge at an intersecting ridge line between the front surface and the outer peripheral surface. The back surface has a flat shape perpendicular to the insert center axis. The outer peripheral surface includes a flank surface coupled. The flank surface is inclined inward in the insert radial direction as extending in the insert axial direction from the front surface side to the back surface side. The front surface includes a rake surface. The rake surface is inclined from a back surface side to a front surface side in the insert axial direction as extending inward in the insert radial direction from the cutting edge.

A cutting insert 2 comprises a peripheral side surface 30 which is parallel to a central axis O of a first end surface 10 and a second end surface 20. The peripheral side surface 30 comprises a first side surface 31 facing a first major cutting edge 11, a second side surface 32 facing a first wiper edge 12, and a third side surface 33 facing a first inner edge 13. A flank 311 of the first major cutting edge 11 and a flank 321 of the first wiper edge 12 are inclined such that the flank 311 and 321 approaches the central axis O as it heads toward the first end surface 10. The flank 311 of the first major cutting edge 11 is located on a different plane from the first side surface 31. The flank 321 of the first wiper edge 12 is located on a different plane from the second side surface 32. Meanwhile, a flank of the first inner edge 13 is located on the same plane as the third side surface 33.

In an indexable rotary cutting tool of the present invention, a cutting edge portion of an insert includes a peripheral cutting edge, a bottom cutting edge, a cutting edge of a corner R, and a chamfered surface, a radial rake angle () of the cutting edge of the corner R has a negative value in an entire edge length region of the cutting edge of the corner R, and the radial rake angle () becomes a minimum value at an intermediate portion located between a pair of boundary points (P, Q) in the cutting edge of the corner R.

In an indexable rotary cutting tool of the present invention, a cutting edge portion of an insert includes a peripheral cutting edge, a bottom cutting edge, a cutting edge of a corner R, and a chamfered surface, a radial rake angle () of the cutting edge of the corner R has a negative value in an entire edge length region of the cutting edge of the corner R, and the radial rake angle () becomes a minimum value at an intermediate portion located between a pair of boundary points (P, Q) in the cutting edge of the corner R.

An indexable rotary cutting tool and insert is capable of performing a high-accuracy cutting process with high efficiency. A twist angle of an outer peripheral cutting edge of the tool has a positive value, an axial rake angle of the cutting edge of a corner R of the tool at a boundary point between the cutting edge of the corner R and the outer peripheral cutting edge has a positive value, the axial rake angle of the cutting edge of the corner R at a reference point has a negative value, and the radial rake angle at least between the boundary point and the reference point in an entire edge length region of the cutting edge of the corner R has a negative value. The radial rake angle at the reference point is smaller than the radial rake angle at the boundary point.

A cutting insert of one aspect includes a first face, a second face, and a third face. The first face includes a first side, a second side, and a first corner. The first face includes a land face connected to the third face. The land face includes a first land face connected to the first corner, a second land face, and a third land face. The first land face includes a first region connected to the second land face and a second region connected to the third land face. When the first face is viewed from the front, a second width of the second region is larger than a first width of the first region in a front view of the first face.

An indexable milling or drilling insert having a 180-degree rotational symmetry about each of the first, second and third axes (X, Y, Z) of a three-dimensional euclidean space. The insert has opposite first and second main surfaces and a peripheral surface extending therebetween. Each main surface has a main abutment surface and at least two rake surfaces. The insert has a through clamping bore which extends along the third axis and opens out to the main surfaces. The peripheral surface has two opposite front surfaces connected to two opposite side surfaces. Each front surface has a pair of outward abutment surfaces and each side surface has a pair of at least partially planar inward abutment surfaces. Each pair of outward abutment surfaces converge outwardly away from the third axis and each pair of inward abutment surfaces converge inwardly towards the third axis.