A cubic boron nitride sintered material tool contains a plurality of cBN grains. cBN grains located on a surface of the cutting edge contain a cubic boron nitride phase, and a hexagonal boron nitride phase. When a ratio I.sub.π*/I.sub.σ* between an intensity of a π* peak derived from a π bond of hBN in the hexagonal boron nitride phase and an intensity of a σ* peak derived from a σ bond of hBN in the hexagonal boron nitride phase and a σ bond of cBN in the cubic boron nitride phase is determined by measuring an energy loss associated with excitation of K-shell electrons of boron, the ratio I.sub.π*/I.sub.σ* of the cBN grain on the surface of the cutting edge is 0.1 to 2, and the ratio I.sub.π*/I.sub.σ* of the cBN grain at a depth position of 5 μm from the surface of the cutting edge is 0.001 to 0.1.

This milling cutter includes: a blade part 10 having a plurality of tips 12 each having an end cutting edge 121 and a peripheral cutting edge 122, and a blade-body portion 11 which is a plate-shaped body with the plurality of tips 12 fixed to an outer circumference thereof and has a groove 113 in accordance with a position of each tip; and a body 20 being rotatable around a rotational axis and having a front-end portion 21 having a front-end surface to which a rear-end surface of the blade-body portion 11 is fixable detachably and in close contact therewith, and a front-end outer-circumferential portion whose outer diameter is 100/100 to 97/100 using an outer diameter of the blade part 10 as a reference, the front-end outer-circumferential portion having a body-side groove 211 continuous to the groove 113 of the blade-body portion 11 contacted closely.

A green body is provided. The green body is made of a superhard material, is used for being fixed on a matrix so as to be machined into a cutting edge part of a cutter. The green body includes a first side surface and a second side surface. Both the first side surface and the second side surface twist at a set helical angle. After being fixed to the matrix, the green body is machined into an edge part for cutting, such as a main cutting edge and a center cutting edge located on the green body made of a same superhard material. The green body is applied to machining the cutting edge of the cutter. A rotating center has a continuous and intact center cutting edge formed by a superhard material.

A tool of the present disclosure includes a tip end portion. The tip end portion has a surface. At least a part of the surface includes a plurality of protrusions, a first recess provided by contact between ends of two adjacent protrusions of the protrusions, and a second recess different from the first recess. The second recess is provided inside at least one of the protrusions or provided to extend across the two adjacent protrusions.

The invention provides a dental milling tool for milling dental materials in the making of dental prostheses. The dental milling tool is a ball-nose end mill having three helical flutes, each flute being associated with a cutting edge, each cutting edge having chip breakers along the curved edges of the ball. The dental milling tool may be formed from a hard material such as carbide based material, ceramic, cermet, superhard materials including polycrystalline diamond (PCD) and cubic boron nitride (CBN), and diamond composite. Alternatively, the dental milling tool may be coated with a hard coating such as diamond coating, diamond-like-carbon (DLC), nitride based coating such as titanium aluminium nitride (TiAlN), aluminium titanium nitride, (AlTiN), and titanium nitride (TiN), and ceramic coating.

A cutting tool includes: a main body portion composed of a cemented carbide; and a front end portion composed of a binderless cubic boron nitride polycrystal, the front end portion being joined to the main body portion. In an axial direction along a rotation axis of the main body portion, the main body portion has a first end and a second end opposite to the first end. The front end portion has a neck portion and an edge portion, the neck portion protruding from the second end along the axial direction, the edge portion being continuous to the neck portion, the edge portion being located at a location distant away from the second end relative to the neck portion in the axial direction. In the axial direction, the neck portion has a third end on the edge portion side and a fourth end opposite to the third end.

A cutting tool rotates about a rotation axis, and includes a tip end portion. The tip end portion includes a partially spherical surface that is brought into contact with a workpiece. The surface is provided with a plurality of recesses disposed apart from each other. An opening edge of each of the plurality of recesses constitutes a cutting edge.

This application describes a method of making a super-hard article that includes a super-hard structure bonded to a substrate. The super-hard structure generally includes a sintered plurality of super-hard grains made from cubic boron nitride. The method generally includes providing raw material powder suitable for sintering the super-hard structure; combining the raw material powder with an organic binder material in a liquid medium to form a paste; providing a substrate assembly having a formation surface area configured for forming a boundary of the super-hard structure, the substrate having a recess coterminous with the formation surface area; extruding the paste into contact with the formation surface area to provide a paste assembly; and heat treating and/or sintering the paste assembly to remove the binder material and provide a pre-sinter assembly.

A prismatic and cylindrical cutting insert for long edge rotary milling applications has multiple indexable cutting edges ranging from four to six or even more depending on the actual milling applications. Each cutting edge of a prismatic or cylindrical cutting insert provides a positive cutting geometry and is equivalent to an indexable cutting edge of a traditional single-sided parallelogram-shaped cutting insert having two indexable cutting edges (often referred as A-Style insert). The prismatic and cylindrical (including tapered or conical) cutting insert may be used for machining a wide range of materials including difficult-to-machine materials, cast-iron and alloys, aluminum and alloys, carbon steels, and fiber reinforced composites.

A sintered body of the present invention is a sintered body including a first material and cubic boron nitride. The first material is partially-stabilized ZrO.sub.2 including 5 to 90 volume % of Al.sub.2O.sub.3 dispersed in crystal grain boundaries or crystal grains of partially-stabilized ZrO.sub.2.