A coated cutting tool comprising a substrate comprising a cubic boron nitride sintered body and a coating layer formed on the substrate, wherein the coating layer comprises a Ti carbonitride layer comprising Ti(C.sub.xN.sub.1-x); an average thickness of the Ti carbonitride layer is 0.5 μm or more and 5.0 μm or less; in the Ti carbonitride layer, R75 is higher than R25; in the Ti carbonitride layer, a texture coefficient TC (111) of a (111) plane is 1.0 or more and 2.0 or less; and in X-ray diffraction measurement of the Ti carbonitride layer, an absolute value of a difference between a maximum value and a minimum value of 2θ is 0.1° or less on the (111) plane when the measurement is performed at each of ψ angles of 0°, 30°, 50° and 70°.

It is an object of the present invention to provide a rotary cutting tool that can divide chips at an appropriate size, suppress the incidence of edge chipping and damage attributed to chips to the cutting tool and a workpiece, extend the tool service life with regard to the machining of hard, brittle materials, and improve machining efficiency. The rotary cutting tool includes a hard coat film 3 coated onto a tip end section of a tool body 1 having a chip discharge groove 2. A rake face 6 is concavely provided in a cutting edge-side chip discharge groove formation surface 4 constituting the chip discharge groove 2 of the tool body 1, from a cutting edge 5 and along the cutting edge 5.

Provided is an end mill which includes an end mill main body having a bottom blade having a convex hemispherical shape, and a hard coating film coated on at least a surface of a distal end portion of the end mill main body. A diameter D (mm) of the bottom blade is 2 mm or less. A ratio W/D of a width W (mm) of a chisel portion to the diameter D (mm) is within a range of 0.020 to 0.060. A ratio L/D of a facing length L (mm) of chip discharge grooves to the diameter D (mm) is within a range of 0.014 to 0.090. A rake angle of the bottom blade in a range in which a chisel edge is formed in the chisel portion is within a range of −15° to −30°.

A rotary cutting tool includes a main body and a shank. The main body has a tip end. The shank is continuous with the main body on the side opposite to the tip end. The main body is provided with a first cutting edge having a positive twist angle, and a second cutting edge having a negative twist angle and separated from the first cutting edge. Each of the first cutting edge and the second cutting edge extends continuously from the tip end to the shank.

The invention relates to a tool part (1) having a main body (3) and at least one cutting zone (5) formed on the main body (3), wherein the cutting zone (5) has a clearance face (7) and a rake face (9) which adjoin each other at a cutting edge (11), wherein the rake face (9) has a coating (13) applied to a main body material of the main body (3) and extending as far as the cutting edge (11), which coating is harder than the main body material. According to the invention, the clearance face (7) is free of the coating (13) in a clearance zone (15) proceeding from the cutting edge (11).

The present invention relates to a cutting tool, which performs, like a drill or a ball end mill, cutting while rotating in a state in which the center of the tip end is in contact with a work material, and includes a wear-resistant layer formed at the tip end thereof, wherein a portion of the wear-resistant layer is selectively removed through tip end polishing from the center of the tip end of the drill or the ball end mill to a predetermined area, so as to restrain micro-brittle wear generated in an ultra-low speed region, and thus remarkably improving the cutting lifespan of the cutting tool such as the drill or the ball end mill.

A covered cutting tool having a cemented carbide and a covering layer formed on the cemented carbide. The covered cutting tool includes a rake face, a flank face, and a cutting edge line part located between the rake face and the flank face. The coating layer includes a compound layer containing a compound having a composition represented by (Al.sub.xTi.sub.1-x)N. The average thickness T.sub.1 of the covering layer in the cutting edge line part and the average thickness T.sub.2 of the coating layer in the rake face at a position 2 mm or more away from the cutting edge line part toward the rake face are within specific ranges and satisfy T.sub.2<T.sub.1. The residual stress S.sub.1 of the cemented carbide in the cutting edge line part and the residual stress S.sub.2 of the cemented carbide in the rake face at a position 2 mm or more away from the cutting edge line part toward the rake face satisfy S.sub.2<S.sub.1.

A cutting blade having a plurality of different coatings on surfaces thereof, including an upper surface, a lower surface, and a side surface connecting the upper surface and the lower surface, wherein the upper surface intersects the side surface to form at least one cutting edge unit, the cutting edge unit includes a main cutting edge and a secondary cutting edge, the upper surface includes at least one set of cutting planes, the cutting planes include a main cutting surface and a secondary cutting surface, the main cutting surface intersects the side surface to form the main cutting edge, the secondary cutting surface intersects the side surface to form the secondary cutting edge, a main coating is provided on the main cutting surface, a secondary coating is provided on the secondary cutting surface, and the main coating and the secondary coating are independent from each other.

To provide a tool that ensures improved durability even when a diamond coating containing boron is formed. A diamond coating (40) includes a first layer (41) that is formed as a layer on a surface layer side of the diamond coating (40) and is regarded as containing no boron, and a second layer (42) positioned on a side of a base material (30) with respect to the first layer (41) and contains at least 1000 ppm or more of the boron. Since the first layer (41) with a larger compressive stress is formed on the surface layer of the diamond coating (40), a crack generation from the surface layer side of the diamond coating (40) during the process can be reduced. Consequently, the durability of a tool (1) can be improved even when the diamond coating (40) containing 1,000 ppm or more of boron is formed.

The present invention relates to a tool (100) for machining workpieces (200), comprising a surface (110) which is at least partially covered by a PVD deposited wear-resistant coating (120), said wear resistant coating (120) comprising one or more wear-resistant layers (121, 122), the coating having a modulus of elasticity, E, which is in a range 300 GPa≤E<350 GPa, and further having a hardness, H, which is greater than 30 GPa.