A turning insert includes a top surface, an opposite bottom surface and a reference plane located parallel to and between the top surface and the bottom surface. A nose portion has a convex nose cutting edge, a first cutting edge and a second cutting edge. The nose cutting edge connects the first and second cutting edges. The first and second cutting edges form a nose angle (α) of 71-85° relative to each other. The nose portion includes a third convex cutting edge adjacent to the first cutting edge and a fourth cutting edge adjacent to the third convex cutting edge. The fourth cutting edge forms an angle (β) of 10-30° relative to a bisector. The distance from at least a portion of the fourth cutting edge to the reference plane increases as the distance from the nose cutting edge increases.

A cutting insert has cutting edges having the same shape and provided at respective corners of a polygon in rotational symmetry about the center axis of the polygon, is clamped in an upright position to a holder, and has a negative side rake angle on a rake face of a side cutting edge. A side cutting edge is present at an intersection ridge between a polygonal face and an outer peripheral face. The outer peripheral face includes a rake face of the cutting edge and a flank of an end cutting edge of another cutting edge different from the side cutting edge. The flank has a positive slope angle in opposition to a negative side rake angle of the side cutting edge. A breaker groove extending in a front-rear direction is formed in the rake face and cuts into the flank, in such a manner as to divide the rake face.

A cutting insert may include a first surface including a corner and a first side, a second surface, a third surface, an inclined surface located between the first surface and the third surface, a first ridgeline located on an intersection of the inclined surface and the first surface, and a second ridgeline located on an intersection of the inclined surface and the third surface. An imaginary straight line passing through a center of the first surface and a center of the second surface may be a central axis. In a cross section which is parallel to the central axis and is orthogonal to the first side, an imaginary straight line connecting the first ridgeline and the second ridge line may be a first straight line, and the inclined surface may include a first inclined surface located more away from the central axis than the first straight line.

Chip discharge during high-feed machining and low-feed machining particularly in a high-depth-of-cut state or the like is improved so as to allow so-called freedom of feed during cutting to be improved. A cutting edge body of a cutting insert includes a front cutting edge formed on one end side in a longitudinal direction, the front cutting edge being a cutting edge formed on an intersecting edge between a peripheral side surface and an upper surface of the cutting edge body having a prismatic shape, a side cutting edge formed on one end side in a lateral direction, a recessed part provided in the upper surface of the cutting edge body to be subsequent to the side cutting edge in the lateral direction, and a wall part having a wavy wall surface formed in a portion of the recessed part and a discrete wall surface formed at a position between the wavy wall surface and the side cutting edge and including a plurality of surfaces which are discrete along the longitudinal direction.

An insert includes a main body extending from a first end toward a second end. The main body includes a cutting edge, a rake face, and a flute. In the rake face, a second rake angle of a second surface region positioned closer to the second end than a first surface region connected to the cutting edge is smaller than a first rake angle of the first surface region. A third rake angle of a third surface region is smaller than the second rake angle, the third surface region being adjacent to the flute rearward in a rotational direction and on an outer peripheral side of the main body.

A turning insert has two opposite main surfaces and a peripheral surface which extends therebetween and has N side surfaces, where 2<N<9. The insert has mirror symmetry about a mid-plane and 360/N degree rotational symmetry about a central axis perpendicular to the mid-plane. The insert has two main edges which each have N main cutting edges and N corner cutting edges. Each main cutting edge has two raised edge portions and a lowered edge portion. Each main surface has N main rake surfaces and N corner rake surfaces. Each main surface further has at least N convex island protrusions and N at least partially convex peninsula protrusions, any and all island protrusions associated with a given main rake surface being located between two adjacent peninsula protrusions, each pair of adjacent peninsula protrusions having at least one island protrusion located therebetween.

A cutting insert may include a first surface, a second surface, a first lateral surface, a second lateral surface, a first cutting edge and a second cutting edge. The first lateral surface may include a first inclined surface located along the first cutting edge, a second inclined surface located along the first inclined surface, a third inclined surface located along the second cutting edge, a fourth inclined surface located along the third inclined surface, and a flat surface located along the second inclined surface and the fourth inclined surface. A second inclination angle of the second inclined surface may be smaller than a first inclination angle of the first inclined surface. A fourth inclination angle of the fourth inclined surface may be larger than a third inclination angle of the third inclined surface.

When seen in a direction perpendicular to a seating surface, the second boundary line has a first portion and a second portion, the first portion having an inclination relative to the second cutting edge portion in a counter clockwise direction, the first portion being located between the first boundary line and an intersection between the second boundary line and a straight line passing through a center of a mounting hole and perpendicular to the second cutting edge portion, the second portion being located opposite to the first portion relative to the intersection, the second portion having an inclination relative to the second cutting edge portion in a clockwise direction.

A turning tool includes a tool body, insert seat and a turning insert. The turning insert has a top surface and an opposite bottom surface, a reference plane between the top and bottom surfaces, and a center axis intersecting the top and bottom surfaces. A circular cutting edge of the insert is concentric in relation to the center axis. The bottom surface includes a set of radial grooves and a set of flat surfaces. The flat surfaces extend in a plane parallel to the reference plane. The insert seat includes a bottom surface and a rear surface. The bottom surface of the insert seat has a first ridge and a support surface, wherein at least one of the flat surfaces of the turning insert is in contact with the support surface. A cross-section of the first ridge is smaller than a corresponding cross section of one of the radial grooves.

The invention relates to a method for producing an indexable insert comprising the following steps: a) providing a starting material for use in an additive manufacturing method in several layers of material; and b) bonding each layer of the starting material in the form of an indexable insert.