Abstract: Ceramic end mill with cutting edge portion including gashes between cutting edges and adjacent in a rotation direction. Center cut edges are formed at end cutting edges close to and facing rotation axis O. Center grooves are formed on rear sides of center cut edges and end cutting edges in the rotation direction continuous with a radial direction. The center grooves are continuous with positions where end cutting edge second surfaces face or approach rotation axis O. End cutting edge second surfaces are laid between center cut edges and end cutting edges. Center grooves are formed between end cutting edge second surfaces and center cut edges positioned on a rear side of end cutting edge second surfaces in the rotation direction. The center grooves pass on rotation axis O. Center grooves double as rake faces of the respective center cut edges and are continuous with the gashes.

Abstract: An embodiment of the invention provides a coated cutting tool having a base material and a hard coating, in which: the hard coating is formed from a nitride or a carbonitride having an Al content of from 50 at. % to 68 at. %, a Cr content of from 20 at. % to 46 at. %, and an Si content of from 4 at. % to 15 at. %, relative to the total amount of metal (including semimetal) elements, and when the total of metal (including semimetal) elements, nitrogen, oxygen, and carbon is designated as 100 at. %, the atomic percentage (at. %) A of metal (including semimetal) elements and the atomic percentage (at. %) B of nitrogen satisfy the relationship 1.03?B/A?1.07; and, in an intensity profile obtained from an X-ray diffraction pattern or a selected area diffraction pattern of a transmission electron microscope, an intensity of a peak from the (200) plane or the (111) plane of a face-centered cubic lattice structure exhibits the maximum intensity.

Abstract: An arc-ion-plated hard coating having a composition represented by (AlxTiyWz)aN(1-a-b)Ob, wherein x, y, z, a and b are numbers meeting by atomic ratio 0.6?x?0.8, 0.05?y?0.38, 0.02?z?0.2, x+y+z=1, 0.2?a?0.8, and 0.02?b?0.10), and having W—O bonds with substantially no Al—O bonds when identified by X-ray photoelectron spectroscopy, and having only a NaCl-type structure in an X-ray diffraction pattern.

Abstract: A multi-flute endmill including a cutting edge part having multiple cutting edges and flutes formed between adjacent cutting edges in a rotation direction around the tool axis O. A rake face of each cutting edge is formed from a rake face of an end cutting edge from the tool axis O side to the outer peripheral side of a shank, an adjacent rake face of a corner R edge that forms a surface different from the rake face of the end cutting edge, and an adjacent rake face of a peripheral cutting edge that forms a surface different from the rake face of the corner R edge. A gash is formed between the rake face of the end cutting edge and a flank of an end cutting edge that is adjacent on a forward side thereof in the rotation direction R.

Abstract: Multi-flute endmill having a cutting edge rake face formed from a side of a rotation axis to a peripheral side in a radial direction, and having an end cutting edge rake face. A peripheral cutting edge rake face adjacent to the end cutting edge rake face forms a face different from the end cutting edge rake face and serves as the rake face of a corner edge. An intersection between a convex ridge line is located in a boundary between the rake faces of the end cutting edge and peripheral cutting edge. A convex ridge line is located in a boundary between the end cutting edge rake face and a bottom surface of the flute is moved into the side of the rotation axis in the radial direction with respect to a boundary between the flank face of a corner edge and the flank face of the end cutting edge.

Abstract: A substantially parallelogramatic insert having a downward inclined main cutting edge and an auxiliary cutting edge in part of a long-side ridgeline and a short-side ridgeline adjacent to a pair of corner cutting edges of an upper surface; the main cutting edge being constituted by first to third straight cutting edges; the first to third straight cutting edges being connected in a bent-line shape with inward obtuse crossing angles when viewed from above, such that the second straight cutting edge is positioned outermost; and cutting edge angles ?1, ?2, ?3 between the rake faces and flanks of the first to third straight cutting edges meeting the relation of ?1>?2>?3.

Abstract: Radius mill and cutting work method that includes a plurality of end cutting edges arrayed around a central axis O and a plurality of arc-shaped radius end cutting edges continuous with the end cutting edges on an outer peripheral side in a radial direction. The end cutting edge is divided into an inner peripheral side end cutting edge and an outer peripheral side end cutting edge in a radial direction. Second surfaces of the plurality of inner peripheral side end cutting edges are coupled at a part close to the axis O. A region of coupled second surfaces is continuous from a region including the axis O to outer peripheral sides of respective inner peripheral side end cutting edges in a radial direction in a strip shape. A width of the strip-shaped region gradually enlarges from axis O side to an outer peripheral side in a radial direction.

Abstract: An insert detachably attached to an indexable rotary cutting tool, comprising an upper surface having cutting edges along the ridgeline, a lower surface, side surfaces, and a center hole for a fastening screw; each cutting edge comprising a corner cutting edge formed in each acute corner portion, and a bottom cutting edge and a peripheral cutting edge formed along the ridgelines on both sides of the corner cutting edge; the bottom cutting edge and the peripheral cutting edge having different clearance angles; a flank of the corner cutting edge comprising an angle-changing surface portion having a clearance angle continuously changing in a region from the bottom cutting edge to the peripheral cutting edge; and the length of the peripheral cutting edge being restricted by a receding portion adjacent to an upper end of the peripheral cutting edge.

Abstract: A multi-flute ball end mill comprising a shank portion, a cutting edge portion having a ball-shaped tip portion, and 3 or more cutting edges formed in the cutting edge portion; each cutting edge being constituted by a peripheral cutting edge having a twist angle ? of 35-45°, and a ball-end cutting edge having a twist angle ? at the outermost peripheral point, the twist angle ? and the twist angle ? meeting the relation of ????7°, such that the ball-end cutting edge is smoothly connected to the peripheral cutting edge; the ball-end cutting edge having a radial rake angle of ?37° to ?11°; the peripheral cutting edge having a radial rake angle of 2-8°; and a center-lowered, inclined cutting edge integrally extending from a tip end of each ball-end cutting edge to a rotation center point, in a tip end portion of the ball portion near the rotation center point.

Abstract: An indexable ball end mill comprising first to third inserts having arcuate cutting edges detachably attached with first to third screws to first to third seats in a semispherical tip end portion of a tool body; a first threaded hole for the first screw slantingly penetrating a slit-shaped first seat; the first insert having an inclined hole to avoid interference between the first screw and the second and third screws; a hole of the first insert and the first screw having at least partially finished surfaces, so that when the first screw penetrates the first insert attached to the first seat, the first insert is precisely positioned by tight engagement of both finished surfaces.

Abstract: A milling insert includes a polygonal tubular insert body which has: rake faces on one polygonal surface thereof, flanks composed of circumferential surfaces adjacent to the polygonal surface, and cutting edges defining a ridge line where the rake faces and flanks intersect each other as cutting edges. The rake faces have serrations where mount portions and valley portions are arrayed alternately to intersect the cutting edges. The ridge line has a waveform shape when the flanks are viewed from above. Bottom portions and top portions of the waveform are formed into concave circular arc portions and convex circular arc portions, respectively, and are alternately repeated. Both of the concave and convex circular arc portions are a ¼ circular arc or more to a ? circular arc or less. Each of the concave circular arc portions is unevenly located between the convex circular arc portions adjacent thereto.