Rotary cutting tool (100) having plurality of major flutes (130) arranged helically opposite to plurality of discontinuous minor flutes (135) and intersecting to form plurality of teeth. Each tooth includes a first cutting edge formed with the major flute and a second cutting edge formed with the minor flute, the first and second cutting edges meeting at an apex and form part of a periphery of a quadrilateral-shaped face portion. The face portion has non-planar surfaces extending from the respective first and second cutting edges that define a relief surface of each cutting edge. First and second cutting edges are arranged on an imaginary cylinder having a center axis coaxial with the axis of rotation of the tool and respective relief surfaces are radially inward of a surface of the imaginary cylinder such that the first and second cutting edges each have a clearance in a rotational direction of the tool.

Rotary cutting tool (100) having plurality of major flutes (130) arranged helically opposite to plurality of discontinuous minor flutes (135) and intersecting to form plurality of teeth. Each tooth includes a first cutting edge formed with the major flute and a second cutting edge formed with the minor flute, the first and second cutting edges meeting at an apex and form part of a periphery of a quadrilateral-shaped face portion. The face portion has non-planar surfaces extending from the respective first and second cutting edges that define a relief surface of each cutting edge. First and second cutting edges are arranged on an imaginary cylinder having a center axis coaxial with the axis of rotation of the tool and respective relief surfaces are radially inward of a surface of the imaginary cylinder such that the first and second cutting edges each have a clearance in a rotational direction of the tool.

A method for manufacturing a dental or medical tool the method comprising the steps of positioning a pre-fluted blank 14 including a stem 24 and a shank 22 within a machine 30, using a probe to identify a position and/or an orientation of at least one flute 26 of the pre-fluted blank 14 and/or the position and/or orientation of an orientation indicator 28 of the pre-fluted blank 14, and using the machine 30 to form a cutting end region 36 at the end of the stem 24 of the pre-fluted blank 14 remote from the shank 22, the flute 26 extending into the cutting end region 36, the machine 30 being controlled to ensure that the cutting end region 36 is correctly orientated relative to the flutes 26 of the pre-fluted blank 14.

A method for manufacturing a dental or medical tool the method comprising the steps of positioning a pre-fluted blank 14 including a stem 24 and a shank 22 within a machine 30, using a probe to identify a position and/or an orientation of at least one flute 26 of the pre-fluted blank 14 and/or the position and/or orientation of an orientation indicator 28 of the pre-fluted blank 14, and using the machine 30 to form a cutting end region 36 at the end of the stem 24 of the pre-fluted blank 14 remote from the shank 22, the flute 26 extending into the cutting end region 36, the machine 30 being controlled to ensure that the cutting end region 36 is correctly orientated relative to the flutes 26 of the pre-fluted blank 14.

In an end mill, eight peripheral cutting edges having a helical shape and a larger outer diameter than that of a shaft portion are in a cutting portion in a circumferential direction. For one peripheral cutting edge of the eight peripheral cutting edges, when a cut length of the peripheral cutting edge along an axial direction is L, a twist angle of the peripheral cutting edge is θ, and a circumferential distance at a lower end of the peripheral cutting edge between the peripheral cutting edge and another peripheral cutting edge adjacent to a tool rotation direction rear side of the peripheral cutting edge is a, n expressed by the following equation is approximately 1 for all of the eight peripheral cutting edges in at least a half region of the cut length from the lower end of the peripheral cutting edge.
n=(L×tan θ)/(2×a)

In an end mill, eight peripheral cutting edges having a helical shape and a larger outer diameter than that of a shaft portion are in a cutting portion in a circumferential direction. For one peripheral cutting edge of the eight peripheral cutting edges, when a cut length of the peripheral cutting edge along an axial direction is L, a twist angle of the peripheral cutting edge is θ, and a circumferential distance at a lower end of the peripheral cutting edge between the peripheral cutting edge and another peripheral cutting edge adjacent to a tool rotation direction rear side of the peripheral cutting edge is a, n expressed by the following equation is approximately 1 for all of the eight peripheral cutting edges in at least a half region of the cut length from the lower end of the peripheral cutting edge.
n=(L×tan θ)/(2×a)

Provided is a cutting insert which is resistant to breakage and can stably be restrained. A cutting insert configured as a vertically mounted insert has a first rake face adjacent to a first major cutting edge, a second rake face adjacent to a second major cutting edge, a restraint surface located further inward than the first and second rake faces to come into contact with a tool body when a second end surface is used, and a reinforcing portion projecting from the restraint surface. The reinforcing portion has a third projecting ridge provided to extend between the first and second rake faces and halve the restraint surface, a first projecting ridge connected to one end of the third projecting ridge to extend so as to cover at least a portion of a boundary between the first rake face and the restraint surface, and a second projecting ridge connected to another end of the third projecting ridge so as to cover at least a portion of a boundary between the second rake face and the restraint surface.

A slotting tool body includes a disc-like cutter portion including opposing forward and rearward cutter portion side surfaces and a cutter portion peripheral surface extending therebetween and a shank portion projecting rearwardly from the rearward cutter portion side surface. The cutter portion includes a number N of angularly spaced apart clamping portions, each having a peripherally disposed insert receiving slot. The cutter portion further includes a flexibility recess recessed in the forward cutter portion side surface and extending to each of the insert receiving slots. A cutting insert is releasably and resiliently clamped in each insert receiving slot to form a rotary slot cutting tool.

A method for manufacturing a workpiece (28) using a milling cutter configured as a conically convex milling cutter (10) is provided. The conically convex milling cutter (10) comprises a shank (12) and a conically convex milling cutter portion (14) connected at the end to the shank (12) directly or through a transition (16). The conically convex milling cutter (10) has a first and a second cutting area (24, 26), wherein the first cutting area (24) is provided on the shank (12) or/and at the transition (16), and wherein the second cutting area (26) is provided on the conically convex milling cutter portion (14). The method comprises the following steps: A) roughing a blank portion (30) using the conically convex milling cutter (10), wherein the latter is inclined relative to a current feed direction (40) at a reference point (38) of the conically convex milling cutter (10) within a first machining angle range (α1, β1) such that machining is performed with the first cutting area (24) of the conically convex milling cutter (10), wherein the second cutting area (26) remains passive during machining, and B) finishing at least a part of the rough blank portion (46) using the conically convex milling cutter (10), wherein the latter is inclined relative to the current feed direction (40) at the reference point (38) of the conically convex milling cutter (10) within a second machining angle range (α2, β2) in such a way that machining is performed with the second cutting area (26) of the conically convex milling cutter (10), wherein the second cutting area (26) engages with the blank (30).

A method for manufacturing a workpiece (28) using a milling cutter configured as a conically convex milling cutter (10) is provided. The conically convex milling cutter (10) comprises a shank (12) and a conically convex milling cutter portion (14) connected at the end to the shank (12) directly or through a transition (16). The conically convex milling cutter (10) has a first and a second cutting area (24, 26), wherein the first cutting area (24) is provided on the shank (12) or/and at the transition (16), and wherein the second cutting area (26) is provided on the conically convex milling cutter portion (14). The method comprises the following steps: A) roughing a blank portion (30) using the conically convex milling cutter (10), wherein the latter is inclined relative to a current feed direction (40) at a reference point (38) of the conically convex milling cutter (10) within a first machining angle range (α1, β1) such that machining is performed with the first cutting area (24) of the conically convex milling cutter (10), wherein the second cutting area (26) remains passive during machining, and B) finishing at least a part of the rough blank portion (46) using the conically convex milling cutter (10), wherein the latter is inclined relative to the current feed direction (40) at the reference point (38) of the conically convex milling cutter (10) within a second machining angle range (α2, β2) in such a way that machining is performed with the second cutting area (26) of the conically convex milling cutter (10), wherein the second cutting area (26) engages with the blank (30).