A cutting part of a cutting insert may include a first surface including a corner, a first side, a first region, a second region and a third region. The first region may be located along the corner and the first side. The second region may be located at a more inner part than the first region. The third region may be located at a more inner part than the second region. A boundary between the corner and the first side may be a first point. A boundary between the first region and the second region may be a second point in a cross section that passes through the first point and is orthogonal to the first side. An imaginary straight line passing through the first point and the second point may be a first imaginary straight line. The first imaginary straight line may intersect with the third region.

A cutting insert in the present disclosure includes an upper surface, a lower surface, a side surface, and an edge. The upper surface includes a first corner part and a second corner part. The edge is located in a region which is located between the first corner part and the second corner part. The edge includes a first edge located at a side of the first corner part, a second edge located at a side of the second corner part, and a third edge located between the first edge and the second edge. The edge has a curvilinear shape being recessed toward the lower surface in a side view. Each of a radius of curvature R1 of the first edge and a radius of curvature R2 of the second edge is smaller than a radius of curvature R3 of the third edge in a side view.

A rotary cutting tool insert according to one embodiment of the present invention includes: an annular rake face provided with at least one recess portion; and a cutting edge formed at an outer circumference of the rake face, the recess portion having a width of more than or equal to 1.2 mm and less than or equal to 3.0 mm in a circumferential direction of the rake face, a distance between the cutting edge and an end of the recess portion at the outer circumference side of the rake face being more than or equal to 0.1 mm and less than or equal to 0.5 mm. According to the rotary cutting tool insert according to the one embodiment of the present invention, roughness of a processed surface and vibration due to a cutting process can be prevented.

A cutting insert of one aspect includes a top surface including a corner portion and a pair of side portions each adjacent to the corner portion, a bottom surface, a side surface located between the top surface and the bottom surface, and a corner cutting edge disposed at the corner portion. In such a cutting insert, the top surface includes a first rake surface located along the corner cutting edge, a raised portion located farther on the inner side than the first rake surface, and a second rake surface located between the corner cutting edge and the raised portion. Moreover, a rake angle at a first region of the second rake surface corresponding to a center of the corner cutting edge is greater than a rake angle at a second region of the second rake surface located beside the first region.

A cutting insert has a cutting corner, having a bisector, located on a top surface of the cutting insert. A chip-control arrangement is located at the cutting corner. The chip-control arrangement includes a projection protruding from the top end face and that extends longitudinally in a direction transverse to, and to opposites sides of, the bisector. The chip-control arrangement also includes a protrusion protruding from the top end face and comprising a protrusion ridge that extends from the projection towards a corner cutting edge at the cutting corner.

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.

According to the present disclosure, a cutting insert includes an upper surface having a polygonal shape and includes a corner, a side surface adjacent to the upper surface, a cutting edge and a protrusion. The cutting edge is located at a ridge part in which the upper surface intersects with the side surface and includes a corner part located at the corner. The protrusion is located on the upper surface. The protrusion includes a first protrusion on a bisector of the corner in a top view. The protrusion further includes a second protrusion adjacent to the first protrusion in a direction orthogonal to the bisector. The second protrusion is closer to the corner than the first protrusion in the top view.

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 holder includes a tool body, a cutting tool insert, and a shim. A coolant conduit system extends through the turning tool holder, a first portion of the coolant conduit system extending through the tool body and an end portion of the coolant conduit system extending through the shim. The end portion of the coolant conduit system includes a through hole extending from a first surface to an opposite second surface of the shim. The end portion has a coolant outlet opening at the second surface, the coolant outlet opening being formed by the shim alone. A jet of coolant from the coolant outlet opening may be directed towards a space expected to have a cutting zone of a workpiece. Further a cutting tool insert arranged to be used in a turning tool holder is disclosed.