A cutting insert has an insert major body which includes two hexagonal faces facing each other and six side faces arranged around the two hexagonal faces, and is rotationally symmetrical at 120° intervals about an insert center line passing through centers of the two hexagonal faces and inversely symmetrical in front and back with respect to the two hexagonal faces, wherein a major cutting edge and an minor cutting edge are alternately formed in a circumferential direction in the single hexagonal face at twelve intersecting ridgeline portions at which the hexagonal faces and the side faces intersect, the major cutting edge is formed to be located at an intersecting ridgeline portion with one hexagonal face while the minor cutting edge is formed to be located at an intersecting ridgeline portion with the other hexagonal face at a single side face.

A cutting insert may include a first surface. The first surface may include a first side, a second side, a first corner, a land surface and an inclined surface. The land surface may include a first land surface, a second land surface and a corner land surface. The first land surface may be located along the first side. The second land surface may be located along the second side. The corner land surface may be located along the first corner. The first land surface may include a part thereof where a first land angle increases as going away from the first corner. The corner land surface may include a part thereof where a corner land angle increases as going away from the first side.

A cutting insert may include a first surface. The first surface may include a first side, a second side, a first corner, a land surface and an inclined surface. The land surface may include a first land surface, a second land surface and a corner land surface. The first land surface may be located along the first side. The second land surface may be located along the second side. The corner land surface may be located along the first corner. The first land surface may include a part thereof where a first land angle increases as going away from the first corner. The corner land surface may include a part thereof where a corner land angle increases as going away from the first side.

A cutting insert 10 comprises a peripheral side surface 16 comprising a plurality of peripheral side surface parts 16A-16H formed so as to be in rotational symmetry with respect to a central axis AX. In the cutting insert 10, a second end surface 14 is provided with a plurality of inclined surface parts 13A-13H formed so as to be in rotational symmetry with respect to the central axis AX and to be recessed from a peripheral edge part 14A.

A cutting insert 10 comprises a peripheral side surface 16 comprising a plurality of peripheral side surface parts 16A-16H formed so as to be in rotational symmetry with respect to a central axis AX. In the cutting insert 10, a second end surface 14 is provided with a plurality of inclined surface parts 13A-13H formed so as to be in rotational symmetry with respect to the central axis AX and to be recessed from a peripheral edge part 14A.

Provided is a cutting insert, which has excellent chip discharge performance even when formed with multiple corners superior in economic efficiency. A first ridgeline at which an upper surface and a circumferential side surface intersect each other includes a plurality of corners disposed at equal intervals and a plurality of main cutting edges disposed one by one between the corners adjacent to each other. A distance between the corners adjacent to each other is equal to or less than 60% of the diameter of a circle inscribed within the ridgeline. The main cutting edges includes a first cutting edge that is linearly formed and a second cutting edge that is linearly formed. The length of the second cutting edge is equal to or less than half the length of the first cutting edge and is positioned closer to a center side of the cutting insert than an extension line of the first cutting edge is. The circumferential side surface includes a first side surface facing the first cutting edge and a second side surface facing the second cutting edge. A clearance angle of the first side surface is smaller than that of the second side surface.

Provided is a cutting insert, which has excellent chip discharge performance even when formed with multiple corners superior in economic efficiency. A first ridgeline at which an upper surface and a circumferential side surface intersect each other includes a plurality of corners disposed at equal intervals and a plurality of main cutting edges disposed one by one between the corners adjacent to each other. A distance between the corners adjacent to each other is equal to or less than 60% of the diameter of a circle inscribed within the ridgeline. The main cutting edges includes a first cutting edge that is linearly formed and a second cutting edge that is linearly formed. The length of the second cutting edge is equal to or less than half the length of the first cutting edge and is positioned closer to a center side of the cutting insert than an extension line of the first cutting edge is. The circumferential side surface includes a first side surface facing the first cutting edge and a second side surface facing the second cutting edge. A clearance angle of the first side surface is smaller than that of the second side surface.

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.

Provided is a cutting insert, within which a burr being generated at an outer edge of a finished surface is inhibited and chipping of the cutting insert is inhibited even when the cutting insert is formed to have multiple corners superior in economical efficiency. The cutting insert has an upper surface, a lower surface on an opposite side to the upper surface, and a circumferential side surface connecting the upper surface and the lower surface to each other. A first ridgeline at which the upper surface and the circumferential side surface intersect each other includes major cutting edges and wiper cutting edges which are alternately disposed one by one, and corners each disposed between each of the major cutting edges and each of the wiper cutting edges. A distance between the corners that are adjacent to each other is equal to or less than 60% of a diameter of an inscribed circle of the first ridgeline. The corner that is positioned at one end of the wiper cutting edge is formed at a deburring cutting edge that intersects the wiper cutting edge at an angle smaller than an angle formed by the major cutting edge and the wiper cutting edge. The corner that is positioned at the other end of the wiper cutting edge is formed at a corner cutting edge having a curvature larger than that of the wiper cutting edge.