A method for forming a stand-alone wafer or a coating on a substrate uses a composite of cubic boron nitride (cBN) particles and other materials, such as nitrides, carbides, carbonitrides, borides, oxides, and metallic phase materials. The wafer or coating may be formed of a thickness up to about 1000 microns for improved wear life. The density of material within the wafer or coating may be varied according to desired parameters, and a gradient of particle sizes for the cBN may be presented across the thickness of the material.

A turning insert includes a top surface, an opposite bottom surface, side surfaces connecting the top surface and the bottom surface and two opposite nose portions. Each nose portion includes a convex nose cutting edge, a first cutting edge and a second cutting edge. The convex nose cutting edge connects the first and second cutting edges. A bisector extends equidistantly from the first and second cutting edges. In a top view the first and second cutting edges on the same nose portion form a nose angle () of 70-85 relative to each other. Each nose portion includes a third convex cutting edge adjacent to the first cutting edge and a fourth cutting edge adjacent to the third cutting edge. In a top view the fourth cutting edge forms an angle () of 0-34 relative to the bisector.

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 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 cutting tool formed by a coating layer on a substrate has cutting edges that feature serrations. The linear dimensions of the serrations may vary from a few nanometers up to 10 microns. The serrations result in a smoother cut edge on the workpiece, particularly when the workpiece is formed of certain materials that are seen as particularly difficult to cut, such as hardened steels.

A cutting insert of one aspect includes a top surface including a first corner portion and a second corner portion; and a top cutting edge. The top cutting edge includes a first corner cutting edge, a first major cutting edge, a second corner cutting edge, and a second major cutting edge. The top surface includes a first breaker protrusion and a second breaker protrusion. A gap between the first breaker protrusion and the first corner cutting edge is larger than a gap between the second breaker protrusion and the second corner cutting edge in a top view, a gap between the first breaker protrusion and the first major cutting edge becomes larger as a distance from the first corner cutting edge increases, and a gap between the second breaker protrusion and the second major cutting edge becomes smaller as a distance from the second corner cutting edge increases.

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.

The purpose of the present invention is to provide a cutting insert which can minimize friction with a chip and maximize heat-radiating performance. To this end, the present invention provides a cutting insert comprising: an upper surface; a lower surface; a plurality of lateral surfaces for connecting the upper surface with the lower surface; a main cutting edge formed between the lateral surface and the upper surface; and a main cutting edge land and a main cutting edge incline formed in series between the main cutting edge and the upper surface, wherein the main cutting edge incline has a first wavy shape in which two or more incline convex parts and two or more incline concave parts are repeated from the main cutting edge land toward the upper surface.

A turning insert includes a top surface, an opposite bottom surface, a reference plane located parallel to and between the top surface and the bottom surface, and a center axis extending perpendicular to the reference plane and intersecting the reference plane (RP), the top surface and the bottom surface. Side surfaces connect the top surface and the bottom surface. Three nose portions are formed symmetrically relative to the center axis. Each nose portion includes a first cutting edge, a second cutting edge and a convex nose cutting edge connecting the first) and second cutting edges. In a top view the first and second cutting edges on the same nose portion form a nose angle of 25-50 relative to each other. The distance from the first cutting edge to the reference plane varies in such a way that that this distance is decreasing at increasing distance from the nose cutting edge.