A cutting tool for performing cutting operations on a workpiece when the cutting tool is rotated about a central axis by a machine tool, the cutting tool includes a generally cylindrical body disposed about the central axis. The generally cylindrical body includes a first end and an opposite second end. The cutting tool further includes a cutting portion and a mounting portion. The cutting portion is disposed at or about the first end of the generally cylindrical body and includes a number of cutting edges structured to engage the workpiece during cutting operations. The mounting portion is disposed at or about the opposite second end of the generally cylindrical body and is structured to be coupled to the machine tool. At least a portion of the generally cylindrical body comprises a molded portion formed via a molding process about the cutting portion in a manner that couples the cutting portion to the generally cylindrical body.

A method for producing a diamond single crystal includes implanting an ion other than carbon into a surface of a diamond single crystal seed substrate and thereby decreasing the transmittance of light having a wavelength of 800 nm, the surface having an off-angle of 7 degrees or less with respect to a {100} plane, and homoepitaxially growing a diamond single crystal on the ion-implanted surface of the seed substrate using a chemical vapor synthesis under synthesis conditions where the ratio N.sub.C/N.sub.H of the number of carbon-containing molecules N.sub.C to the number of hydrogen molecules N.sub.H in a gas phase is 10% or more and 40% or less, the ratio N.sub.N/N.sub.C of the number of nitrogen molecules N.sub.N to the number of carbon-containing molecules N.sub.C in the gas phase is 0.1% or more and 10% or less, and the seed substrate temperature T is 850 C. or more and less than 1000 C.

A cutting insert that has, in an upper surface, a convex portion including a main portion having a flat upper end surface, a first portion projecting from the main portion to a corner portion of the upper surface, a second portion projecting from the first portion to the corner portion, and a third portion projecting from the second portion to the corner portion. Upper end heights of the second portion and the third portion are fixed toward the corner portion, respectively. The first portion and the second portion are connected by a first flat inclined wall surface, the second portion and the third portion are connected by a second wall surface of a convex curved surface, and a front end of the third portion and the breaker groove are connected by a third wall surface of a convex curved surface.

A method for designing a cutting edge of a cutting element configured for removing material from a workpiece to leave therein a desired end profile (B22,B24,B26). The method comprises the steps of modeling a desired end profile (B22,B24,B26) of the workpiece, the profile having a longitudinal axis and being defined by a bottom surface (B12), a side surface (B16) and an adjustment surface (B14) extending therebetween; defining a lead profile plane (RP.sub.L) and an trail profile plane (RP.sub.T) spaced therefrom, each of the planes being oriented perpendicular to the longitudinal axis; determining a profile contour defined by the intersection line between the end profile (B22,B24,B26) and the lead profile plane (RP.sub.L). The contour profile includes a bottom contour, an adjoining contour and a side contour defined as the intersection lines between the lead profile plane (RP.sub.L) and the bottom surface (B12), the adjustment surface (B14) and the side surface (B16) respectively; designing a rake surface and a relief surface, the intersection line between which defines a cutting edge lying in the adjoining surface (B14) and spanning between the lead profile plane (RP.sub.L) and the trail profile plane (RP.sub.T). The cutting edge is designed such that in any reference plane (RP; FIG. 6A) oriented perpendicularly to the cutting edge, the intersection between each of the rake surface and the relief surface with the reference plane (RP) defines a respective rake line (RK; FIG. 7) and relief line (RF; FIG. 7), the angle (.sub.B) between the lines RK,RF) being equal to or smaller than a similar angle (.sub.B) taken along each of a plurality of similar reference planes (RP) disposed between the reference plane (RP.sub.n) and the lead profile plane (RP.sub.L).

A method for manufacturing a cubic boron nitride cutting tool including a base metal and sintered cubic boron nitride compact at a corner portion of the base metal, capable of improving the accuracy of the center height and reducing the angle of inclination or width of a negative rake face; and the cubic boron nitride cutting tool. The method includes grinding the compact by pressing it against an end face of a grindstone of a grinder to form flank and rake faces on the compact while the base metal of the cutting tool is held by a chuck of the grinder, so that the compact is substantially ground. The rake face is formed to be recessed from a top face of the base metal or only a portion of the compact that protrudes from a base-metal rake face is ground while the tool is continuously held by the chuck.

An object is to prolong the life of a cubic boron nitride cutting tool used for cutting a heat-resistant alloy. A cubic boron nitride cutting tool includes an edge tip made of a sintered cubic boron nitride compact including cubic boron nitride particles; and a base metal that holds the edge tip at a corner portion of the base metal, wherein a cutting edge formed on the edge tip of the tool has a positive rake angle.

Problem: To provide a cutting tool formed from a silicon nitride-based sintered body having high fracture resistance and having residual stress of a rake face and a flank face in an appropriate range. Solution: A cutting tool (1) formed from a silicon nitride-based sintered body containing not less than 50 volume % silicon nitride-based phase and from 10 to 30 volume % titanium nitride phase, uses an intersection ridge portion of a rake face (2) and a flank face (3) as a cutting edge (4), has a residual stress applied to the titanium nitride phase that is tensile stress, and is such that the tensile stress applied to the titanium nitride phase in the rake face (2) is greater than the tensile stress applied to the titanium nitride phase in the flank face (3).

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.

A method of making a body of polycrystalline superhard material comprising placing an aggregated mass of grains of superhard material into a canister, placing a ceramic layer either in direct contact with the aggregated mass of grains of superhard material or in indirect contact therewith, the ceramic layer being spaced from the grains by an interlayer of material when present, the ceramic layer having a surface with surface topology, the surface topology imprinting a pattern in the aggregated mass of grains of superhard material complementary to the surface topology, the ceramic material and the material of the interlayer being such that they do not react chemically with the superhard material and/or a sinter catalyst material for the grains of superhard material. The aggregated mass of grains of superhard material and ceramic layer are subjected to a pressure of greater than 5.5 GPa and sintered to form a body of polycrystalline superhard material having a surface topology complementary to the surface topology of the ceramic layer. The ceramic layer and interlayer if present are then removed from the body of polycrystalline material. There is also disclosed a body of polycrystalline superhard material having a surface topology on a first surface, the first surface being substantially free of material from a canister used in formation of the body of polycrystalline superhard material.

A cutting insert is used in a cutting edge replaceable rotary cutting tool. The cutting insert includes a first cutting edge formed on an intersecting ridge portion between a first end surface of two opposite end surfaces and a circumferential side surface, and a first depressed portion formed along a part of the first cutting edge. The first depressed portion is provided to form a larger rake angle at the first cutting edge than that at a part not having the first depressed portion of the first cutting edge.