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 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 according to an aspect includes a top surface and a side surface. At least a part of a ridge line where the top surface and the side surface intersects is a cutting edge. The cutting edge includes a first portion located at a corner portion, a second portion adjacent to the first portion, a third portion close to the second portion, a fourth portion close to the third portion, and a fifth portion adjacent to the fourth portion. When viewed from directly above, a curvature radius of the second portion is less than a curvature radius of the first portion, a curvature radius of the third portion is greater than the curvature radius of the first portion, and a curvature radius of the fourth portion is less than the curvature radius of the third portion.

A turning insert arranged for longitudinal turning of metal work pieces includes a nose cutting edge that slopes from a trailing cutting edge in direction towards a leading cutting edge. A turning tool is also disclosed.

To provide a cutting insert that readily fragmentizes chips, and that has excellent durability.

At least a cutting part of a cutting insert is formed of a sintered compact. The sintered compact includes a chip breaker that is a recessed portion in which a partial region of a cutting part upper surface is depressed downward. The chip breaker includes a downward inclined surface, an upward inclined surface, a jutting portion that juts out along a first axial line that passes through a distant end of a cutting edge, and a stepped surface that adjoins the jutting portion in a Y axis direction orthogonal to the first axial line. An upper end of the jutting portion is formed at a height of an upper stage. The stepped surface is formed at a height of an intermediate stage at a part closest to the first axial line.

A method and a device for machining a workpiece rotating about a rotational axis. The machining point moves along the cutting edge of a cutting edge plane and the surface to be machined in a rolling movement on an advancement plane not intersected by the rotational axis. A pivot drive implements a large enough pivot angle so that a first workpiece surface is machined by a machining point moving along the first cutting edge in a first machining step. In a second machining step, a second workpiece surface is machined, wherein the machining point moves along the second cutting edge and the second workpiece surface. The cutting edge has a curvature radius smaller than the distance from the pivot axis of the holder to the cutting edge. The holder can additionally be displaced on the advancement plane with a movement component in a direction transverse to the rotational axis.

In an embodiment, a cutting insert includes an upper surface, a one or more side surfaces, and a cutting edge. The upper surface includes a first corner portion, and a first side that is adjacent to the first corner portion. The side surfaces are adjacent to the upper surface. The cutting edge is disposed on at least a portion of a section where the upper surface and the side surfaces intersect. The cutting edge includes first, second, third and fourth cutting edges. The first cutting edge is disposed at the first corner portion and has a convex curved shape. The second cutting edge is next to the first cutting edge, and has a linear shape. The third cutting edge is next to the second cutting edge, and has a convex curved shape. The fourth cutting edge is next to the third cutting edge on the first side.

A wiper insert and a tool with the same. The wiper insert includes a tool body, and the tool body includes a cutting part which is used to cut a workpiece. The cutting part includes a plurality of wipers. Adjacent wipers are connected by a transition surface, and the minor cutting edge angles of the plurality of wipers are set differently. With the technical solution of the present application, the problem in the prior art that the wiper inserts lose their wiping effects when they are mounted on different tool holders is solved effectively.

A cutting insert of an embodiment includes a cutting edge located at an intersecting part of an upper surface and a side surface. The cutting edge includes a corner cutting edge, a major cutting edge, and a flat cutting edge. The upper surface includes a first land surface located along the corner cutting edge, a second land surface located along the major cutting edge, and a third land surface located along the flat cutting edge. A maximum value of a width of the third land surface is smaller than a maximum value of a width of each of the first land surface and the second land surface in a top view.

A cutting insert according to an aspect includes a top surface and a side surface. At least a part of a ridge line where the top surface and the side surface intersects is a cutting edge. The cutting edge includes a first portion located at a corner portion, a second portion adjacent to the first portion, a third portion close to the second portion, a fourth portion close to the third portion, and a fifth portion adjacent to the fourth portion. When viewed from directly above, a curvature radius of the second portion is less than a curvature radius of the first portion, a curvature radius of the third portion is greater than the curvature radius of the first portion, and a curvature radius of the fourth portion is less than the curvature radius of the third portion.