The cutting insert is provided with: a top surface, a bottom surface, a side surface, a cutting edge located at the intersection portion of the top surface and the side surface; a through hole located from the top surface to the bottom surface; a projecting portion extending from a corner section to a through hole side; and a rake surface located between the cutting edge and the projecting portion. A boundary line between the rake surface and the projecting portion comprises a first end. In a top view, a bisector of the corner section intersects the cutting edge at a first point and intersects a top edge section of the through-hole at a second point. The first end is located closer to the through-hole side than a perpendicular line that passes through a midpoint of a line segment connecting the first point and the second point.

A cutting insert includes a rake face, a flank face, a cutting edge formed at a ridge where the rake face and the flank face intersect, a land provided on the rake face along the cutting edge, a breaker groove provided in the rake face inside of the land, and a curved surface formed between a groove surface of the breaker groove and the land. A radius of curvature of the curved surface is 0.5 mm or greater.

A cutting insert comprises an upper surface including a first corner, and a second and third corner, respectively, adjacent to both sides of the first corner. The upper surface sequentially includes a rake surface along an upper cutting edge, inclined toward a lower surface, going inward from the upper cutting edge at a rake angle on a basis of a perpendicular plane perpendicular to a central axis extending between the upper and lower surfaces, and a connection surface more inward than the rake surface, inclined toward the lower surface, going inward at a connection angle on the basis of the perpendicular plane. An intersecting part of the rake surface and the connection surface includes a highest position in a portion of the intersecting part corresponding to a minor rake surface. A cutting tool with cutting insert, and a method of producing a machined product using the cutting tool are provided.

A cutting insert according to one embodiment of the present invention comprises an upper surface, a lower surface, a lateral surface, a cutting edge, and a fastening hole, wherein the cutting edge includes a main cutting edge, a nose R part connected to the main cutting edge, and a sub-cutting edge connected to the nose R part, the upper surface includes a land part adjacent to the cutting edge, an inclined surface downwardly inclined from the land part, and an upper surface bottom part extending from the inclined surface, first and second protrusion parts are formed respectively, in which the first protrusion part is connected to a main cutting edge land part and formed on a main cutting edge inclined surface at a portion at which a nose R part inclined surface ends and the second protrusion part is connected to a sub-cutting edge land part and formed on a sub-cutting edge inclined surface at a portion at which the nose R part inclined surface ends, and no protrusion is present on the nose R part inclined surface.

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.

A cutting insert according to one aspect of the present invention includes a polygonal columnar shape, and includes an upper surface, a lower surface and a side surface located between the upper surface and the lower surface, and a cutting edge is formed at an intersecting portion between the upper surface and the side surface, the upper surface includes a main portion of a convex shape including a flat upper end surface, a first projecting portion which projects from the main portion to a corner portion of the upper surface, and a pair of second projecting portions which each project from the first projecting portion to a periphery of the upper surface to interpose a region between a front end of the first projecting portion and the corner portion, and each of upper ends of the pair of second projecting portions is spaced part from the first projecting portion.

A cermet insert includes a first surface, a second surface, a cutting edge, a third surface located opposite to the first surface, and a through hole extending from the first surface to the third surface. An inner wall constituting the through hole has, at least in a center portion, a binder-phase-rich layer having a higher binder phase content than an interior of the base. A thickness T1 of the binder-phase-rich layer at the center portion is larger than a thickness T2 of the binder-phase-rich layer at an end portion. The thickness T1 is 1 ?m or more and 20 ?m or less, the thickness T2 is 0.2 ?m or more and 6 ?m or less. The first surface includes a chip breaker. An arithmetic mean roughness Ra of the chip breaker is 0.05 ?m or less when a cut-off value is 0.08 mm.

A cutting insert has a bottom supporting surface, a center cutting edge, two secondary cutting edges, realized on both sides of the center cutting edge and offset in relation to the center cutting edge, and two transition edges connecting the center cutting edge to the secondary cutting edge adjacent in each case. The two secondary cutting edges are realized in each case vertically offset and, where applicable, also offset in depth with respect to the center cutting edge and are laterally spaced from the center cutting edge. The transition edges, in each case in a non-edge-overlapping region, have at least over a portion an inclination n where 2n20 in relation to a height direction which extends at right angles with respect to a main extension plane of the supporting surface.

A cutting insert includes a land and a breaker flute on a rake face, the land providing a cutting edge by intersecting a flank face. The breaker flute includes breakers. A width T of a portion of the land that extends along a portion of the cutting edge that is at a round corner portion is 0.05 mm<T<0.15 mm. A plurality of crest portions each extending over the entirety of the portion of the cutting edge that is at the round corner portion are provided on a sloping surface of the breaker flute that is on a land side. The crest portions are arranged side by side in a depth direction of the breaker flute. A rake angle of at least one of inclined surfaces that form each of the crest portions is expressed as >20.

The present invention relates to a cutting insert having a cutting edge which is provided with a corner section that forms a convex arc shape when seen in a planar view from the direction facing the rake face and a pair of linear sections that are in contact with the corner section at the both ends thereof. The cutting edge is provided with a first region along the corner section, a second region along the linear section and a third region positioned between them, and a cross-sectional area of the insert main body on a cross-section orthogonal to the cutting edge in a range of width which is a radius R (mm) of the corner section is made largest in the third region, smallest in second region and between them in the first region in terms of size.