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 minor cutting edge has a first minor cutting edge and a second minor cutting edge that extends inward of the insert in a direction of an insert short side face axial line, as the second minor cutting edge extends from the first minor cutting edge in a direction of an insert major face axial line. A flank face of the second minor cutting edge is inclined outward of the insert in the direction of the insert short side face axial line, as the flank face extends from the second minor cutting edge in the direction of an insert long side face axial line, and is inclined outward of the insert in the direction of the insert short side face axial line, as the flank face extends from a major face adjacent to the flank face in the direction of the insert major face axial line.

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 positioning tool is configured for retaining an undersized, bore-less indexable cutting insert. The cutting insert may have a triangular or trigonal shape. The positioning tool has an outwardly facing insert retaining surface which has an elongated shape which corresponds to a shape of a side of the undersized cutting insert. The positioning tool is configured to retain the cutting insert using magnetic force, electrostatic force and/or adhesive force. A milling kit may include such a positioning tool, along with one or more such undersized cutting inserts. The milling kit may optionally also include a milling tool having one or more insert pockets configured to accommodate such cutting inserts, and may further optionally include one or more clamping screws configured to clampingly and externally secure such inserts in the pocket without passing through the inserts.

A cutting insert comprises: a first end surface and a second end surface which are opposed to each other; a peripheral side surface which extends so as to connect the first end surface and the second end surface; a first cutting edge which is arranged in an intersecting edge between the first end surface and the peripheral side surface; and a second cutting edge which is arranged in an intersecting edge between the second end surface and the peripheral side surface. The peripheral side surface includes a first flank which is connected to the first cutting edge and an intermediate peripheral side surface portion which is arranged closer to the second end surface than the first flank. The first flank extends in a direction perpendicular to the first end surface. The intermediate peripheral side surface portion protrudes outward from the first flank.

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 at when working with axial depths of cut of about three times outside tool diameter or less.

A slotting tool body includes a disc-like cutter portion and a shank portion projecting rearwardly therefrom. The cutter portion includes a resilient clamping portion having a peripherally disposed insert receiving slot. The shank portion includes a peripherally disposed forward shank recess that is axially adjacent the cutter portion. A radially inward portion of the insert receiving slot merges in the rearward direction with the forward shank recess. A cutting insert is releasably and resiliently clamped in the insert receiving slot to form a rotary slot cutting tool. The cutting insert includes two cutting portions that each include a long and short insert lateral extension, the long insert lateral extension being longer than the short insert lateral extension. The longest insert lateral extensions are orated on opposite sides of the cutting insert.

A positioning tool is configured for retaining an undersized, bore-less indexable cutting insert. The cutting insert may have a triangular or trigonal shape. The positioning tool has an outwardly facing insert retaining surface which has an elongated shape which corresponds to a shape of a side of the undersized cutting insert. The positioning tool is configured to retain the cutting insert using magnetic force, electrostatic force and/or adhesive force. A milling kit may include such a positioning tool, along with one or more such undersized cutting inserts. The milling kit may optionally also include a milling tool having one or more insert pockets configured to accommodate such cutting inserts, and may further optionally include one or more clamping screws configured to clampingly and externally secure such inserts in the pocket without passing through the inserts.

A cutting insert (1) comprises: a first end surface (2) and a second end surface (3) which are opposed to each other; a peripheral side surface (4) which extends so as to connect the first end surface (2) and the second end surface (3); a first cutting edge (5a) which is arranged in an intersecting edge between the first end surface (2) and the peripheral side surface (4); and a second cutting edge (5b) which is arranged in an intersecting edge between the second end surface (3) and the peripheral side surface (4). The peripheral side surface (4) includes a first flank (4a1) which is connected to the first cutting edge (5a) and an intermediate peripheral side surface portion (4b) which is arranged closer to the second end surface (3) than the first flank (4a1). The first flank (4a1) extends in a direction perpendicular to the first end surface (2). The intermediate peripheral side surface portion (4b) protrudes outward from the first flank (4a1).

A multi-flute ball end mill of the present invention includes: a shank portion configured to rotate about a rotational axis; a cutting edge portion; three or more ball edges formed on the cutting edge portion; gashes formed between the ball edges; peripheral cutting edges continuous with end portions of the ball edges on the shank portion side; and flutes formed between the peripheral cutting edges continuously with the gashes. The degree of curvature of the ball edges is 35% to 55%. Each of the gashes includes four faces of a rake face of each of the ball edges, a gash wall face, a first gash face, and a second gash face. The second gash face is formed such that the closer the second gash face is to the rotation center point, the more inwardly the second gash face enters a second face of each of the ball edges.