In an end mill body made of ceramic, a corner R rake face is formed in such a manner as to contain a point B and at least a region B, not a region A located on a side toward an end cutting edge. In other words, a first end portion of a cutting edge on a peripheral edge portion of the corner R rake face is formed on a peripheral edge of the region B of a corner R cutting edge, and a second end portion of the cutting edge reaches at least the point B. As a result, partial breakage of the corner R cutting edge is unlikely to occur in the course of cutting. That is, since the corner R rake face is formed in such a manner as to start from the first end portion located apart from a point A, which is the intersection of the end cutting edge and the corner R cutting edge, and such that the second end portion reaches the point B, a large cutting load is unlikely to be imposed on the starting point of the corner R rake face. Therefore, the corner R cutting edge is unlikely to be chipped.

A cutting tool includes a shaft portion and a plurality of edge region groups. The ridgeline between the first rake face portion and the first flank face portion constitutes a first cutting edge portion. The ridgeline between the second rake face portion and the second flank face portion constitutes a second cutting edge portion. As seen from the direction perpendicular to a plane tangent to the outer peripheral surface, in a state where the central axis overlaps a first end on the front end side of the first cutting edge portion, the inclination angle of the first cutting edge portion relative to the central axis is larger than the inclination angle of a straight line relative to the central axis, the straight line connecting the first end to a second end on the front end side of the second cutting edge portion.

An end mill includes a bar-shaped body, a cutting edge, a gash, a first flute, and a second flute. The body extends from a first end to a second end along a rotation axis. The cutting edge is located at a side of the first end of the body. The gash is located adjacent to the cutting edge. The first flute surrounds the gash and spirally extends from the gash toward the second end. The second flute surrounds the first flute and spirally extends from the first flute toward the second end. A depth of the first flute is greater than a depth of the second flute in a cross section orthogonal to the rotation axis.

A rotatable cutting tool for machining of a honeycomb core includes a front end; a rear end; a peripheral surface extending between the front and rear ends; a set of helical flutes formed in the peripheral surface at a first helix angle 4565, having a first depth; and a set of helical ridges. At least one helical groove formed in the peripheral surface at a second helix angle 90<100, has a second depth, which is smaller than the first depth. The at least one helical groove intersects the helical ridges so that a plurality of cutting teeth are formed on each helical ridge. Each cutting tooth includes a second ridge formed in a transition between two lands, a cutting edge and a clearance edge join in a tooth tip constituting the radially outermost point of the cutting tooth.

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 rotary tool in a non-limiting embodiment of the present disclosure has a columnar shape. A first flute has a first helix angle having a positive value. A second flute has a second helix angle having a negative value. An outer peripheral surface includes a first outer peripheral surface and a second outer peripheral surface. A second outer peripheral surface is located on a rear side in a rotation direction of a rotation axis with respect to the first outer peripheral surface. The first outer peripheral surface includes a first flank surface extending along a first cutting edge, and a second flank surface extending along a second cutting edge. The first flank surface includes a first enlarged part whose width increases as coming closer to the second flank surface.

An end mill that facilitates discharge of chips and enables twining of chips to be suppressed is provided. An end mill (10) includes a tool body, a helical flute, an end cutting edge, a flank, and a gash. The gash forms a cutting face of the end cutting edge. The cutting face is formed as a recessed curved surface and the end cutting edge comprised of a ridge between the cutting face and the flank is concavely curved.

A rotary cutting tool. The tool has a body with outside diameter (OD), and outer surface, and a longitudinal axis, a plurality of flutes, helical in some embodiments. Flutes include a narrow leading edge land portion with circular segment profile and having flute cutting edge portions along a substantially uniform circumferential location, with an eccentric relief margin rotationally rearward of the narrow leading edge land portions. Face portions are provided with face cutting edge portions, and with a first dish portion adjacent each of the cutting edge portions sloping inwardly and downwardly generally toward a central longitudinal axis at a first dish angle alpha () Corner blend portions extend from flute cutting edge portions to the face cutting edge portions. Corner blend portions are provided in a variety of profiles, including an embodiment wherein the profile of the corner blend portions are truncated before the segment of curvature becomes tangential to the face cutting edge portions. Large core diameters of cutting tools are provided, which gives high strength when working with axial depths of cut of about three times outside tool diameter or less.

A special end cutting edge attached cutter for carbon fiber reinforced polymer/plastic with designable micro-tooth configuration, having an end cutting edge, a peripheral cutting edge with variation inverse helical groove, a peripheral cutting edge with constant inverse helical groove and a shank. Two parallel V-shaped chip pockets are designed on the end cutting edge of the cutter in two cutting edge directions which are symmetrical around a cutter axis as a center. The structure may enhance chip removal performance during high-speed milling of impenetrable slots and impenetrable windows, reduce wear of the end cutting edge, conduct configuration design for micro-teeth of the peripheral cutting edge, reduce the cutting thickness of the micro-tooth cutting edges, and effectively solve the problem of damage of the micro-tooth edges. A section of peripheral cutting edge with variation left-hand inverse helical flute angle is designed near the end cutting edge.

A rotatable cutting tool includes an elongate body and at least one helical flute extending over a length of the elongate body, the helical flute having a first end and a second end. The flute includes a cutting-edge with a first radius from a longitudinal center of the cutting tool, a trailing edge with a second radius from a longitudinal center of the cutting tool, wherein the second radius is smaller than the first radius, a flute surface between the cutting-edge and the trailing edge, the flute surface including a maximum radius at the cutting-edge and a plurality of foam chip shedding exclusions spaced along the cutting-edge of the helical flute, each of the foam chip shedding exclusions providing a gap in the cutting-edge where the radius within the gap is smaller than the first radius. The first radius defines a maximum tool cutting radius for the cutting tool. A gap distance between the foam chip shedding exclusions and the maximum tool cutting radius equals at least 15% of a radial height of the flute.