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 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 insert includes a body made of a ceramic material. The body has a first surface, a second surface and at least one flank surface extending between the first surface and the second surface. The first surface includes a chip forming feature extending in a radially outwardly direction to a cutting edge and extending in a radially inwardly direction to an inner edge. The chip forming feature includes a front wall that slopes downward from the cutting edge radially inward toward a rounded bottom surface and a back wall that slopes upward from the rounded bottom surface radially inward to the inner edge. The chip forming feature can include an optional land surface between the cutting edge and the front wall.

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.

The cutting device includes a rotating portion for rotating the cutting tool in a rotation axis line of the cutting tool and a traveling means for making the cutting tool travel relative to a workpiece. The rotating means and the traveling means rotates the outer peripheral surface of the cutting tool and makes the cutting tool travel, having the outer peripheral surface function as the rake surface, so as to perform cutting machining.

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.

In a cutting insert according to an embodiment of the present invention, an upper cutting edge includes, sequentially from a first corner to a second corner, a corner cutting edge, a minor cutting edge inclined as separating from the corner cutting edge at a first inclination angle on a basis of a vertical plane perpendicular to a central axis extending between upper and lower surfaces, and a major cutting edge inclined as separating from the minor cutting edge at a second inclination angle on the basis of the vertical plane so as to become more closer to the lower surface than the minor cutting edge. A cross section of a rake surface obtained by cutting an inwardly located end portion thereof along a direction of the central axis has a straight line shape or concave shape in a region crossing over at least a minor rake surface and a major rake surface. A cutting tool with the cutting insert, and a method of manufacturing a machined product by using the cutting tool are also provided.

A cutting insert may have an upper surface, lower surface, side surface, and a polygonal plate shaped to form a cutting edge at a ridgeline where the upper surface and the side surface intersect. The upper surface has a major part having a flat upper end surface, a first protrusion protruding from the major part toward a corner part of the upper surface, a second protrusion protruding from the first protrusion toward the corner part, and a pair of projections located between the second protrusion and the cutting edge. A height of an upper end of the first protrusion from the lower surface is lower than a height of the upper end surface of the major part and is higher than a height of the cutting edge. A height of an upper end of the second protrusion from the lower surface is equal to the height of the cutting edge.