A hobbing tool includes a hob body having at least one axially extending slot, and at least one cassette removably disposed in the at least one slot. The at least one cassette includes at least one seating recess having at least a bottom abutment surface and two side abutment surfaces. At least one cutting insert is removably mounted in the at least one seating recess. The at least one cutting insert has at least one bottom supporting surface and two side supporting surfaces that abut the bottom abutment surface and the two side abutment surfaces when the at least one cutting insert is received in the at least one seating recess. The hob body includes a plurality of axially extending slots. The hobbing tool also includes a corresponding plurality of cassettes removably mounted in the plurality of axially extending slots. Each cassette of the plurality of cassettes is identical to every other cassette of the plurality of cassettes.

A surface-coated cutting tool comprises a hard coating layer that includes a TiAlN layer and is provided on a surface of a cutting tool body. In case the composition of the TiAlN layer is expressed by a formula: (Ti.sub.xAl.sub.1-x)N, 0.10x0.35 (here, x is in atomic ratio) is satisfied. In the TiAlN layer, a high Ti band-like region is present in a direction at 30 degrees or less with respect to a line normal to the surface of the cutting tool body. An average composition X of the Ti component in the high Ti band-like region satisfies (x+0.01)X(x+0.05), an average width W of the high Ti band-like region is 30 to 500 nm, and an average area ratio St of the high Ti band-like region is 3 to 50 area %.

A clearance angle, of a blade-like tool or tool tooth of a tool for hob peeling workpieces is determined by defining the rake face contour of the tool and calculating the progression of path movement of the rake face during chip-breaking hob peeling, taking into account a pre-determinable transmission ratio between the tool and the workpiece determined by the respective number of teeth, and the desired tooth cross-section contour of the tool, and determining a tangential speed for points of the cutting edge of the tool during chip-breaking, wherein hob peeling is determined in the form of vectors that are displayed graphically as bundles for each point on the cutting-edge and a closed envelope surface is determined, which plus a desired clearance angle is selected as the shape for the flank face contour of the tool or of the flank face of the tool tooth. A tool is also provided.

A clearance angle, of a blade-like tool or tool tooth of a tool for hob peeling workpieces is determined by defining the rake face contour of the tool and calculating the progression of path movement of the rake face during chip-breaking hob peeling, taking into account a pre-determinable transmission ratio between the tool and the workpiece determined by the respective number of teeth, and the desired tooth cross-section contour of the tool, and determining a tangential speed for points of the cutting edge of the tool during chip-breaking, wherein hob peeling is determined in the form of vectors that are displayed graphically as bundles for each point on the cutting-edge and a closed envelope surface is determined, which plus a desired clearance angle is selected as the shape for the flank face contour of the tool or of the flank face of the tool tooth. A tool is also provided.

A clearance angle, of a blade-like tool or tool tooth of a tool for hob peeling workpieces is determined by defining the rake face contour of the tool and calculating the progression of path movement of the rake face during chip-breaking hob peeling, taking into account a pre-determinable transmission ratio between the tool and the workpiece determined by the respective number of teeth, and the desired tooth cross-section contour of the tool, and determining a tangential speed for points of the cutting edge of the tool during chip-breaking, wherein hob peeling is determined in the form of vectors that are displayed graphically as bundles for each point on the cutting-edge and a closed envelope surface is determined, which plus a desired clearance angle is selected as the shape for the flank face contour of the tool or of the flank face of the tool tooth. A tool is also provided.

A clearance angle, of a blade-like tool or tool tooth of a tool for hob peeling workpieces is determined by defining the rake face contour of the tool and calculating the progression of path movement of the rake face during chip-breaking hob peeling, taking into account a pre-determinable transmission ratio between the tool and the workpiece determined by the respective number of teeth, and the desired tooth cross-section contour of the tool, and determining a tangential speed for points of the cutting edge of the tool during chip-breaking, wherein hob peeling is determined in the form of vectors that are displayed graphically as bundles for each point on the cutting-edge and a closed envelope surface is determined, which plus a desired clearance angle is selected as the shape for the flank face contour of the tool or of the flank face of the tool tooth. A tool is also provided.

A cutting edge of a machining tool and a surface treatment method for the same. A cutting edge of a machining tool and a region in the vicinity of the cutting edge, e.g. a region of at least 1 mm and preferably at least 5 mm from the cutting edge, are defined as a treatment region; and substantially spherical injection granules having a median diameter of 1 to 20 m are injected onto the treatment region with an injection pressure of 0.01 MPa to 0.7 MPa in order for dimples having an equivalent diameter of 1 to 18 m and preferably 1 to 12 m, and a depth at least equal to 0.02 m and at most equal to 1.0 m to be formed such that the projected surface area of the dimples is at least equal to 30% of the surface area of the treatment region.

A cutting edge of a machining tool and a surface treatment method for the same. A cutting edge of a machining tool and a region in the vicinity of the cutting edge, e.g. a region of at least 1 mm and preferably at least 5 mm from the cutting edge, are defined as a treatment region; and substantially spherical injection granules having a median diameter of 1 to 20 m are injected onto the treatment region with an injection pressure of 0.01 MPa to 0.7 MPa in order for dimples having an equivalent diameter of 1 to 18 m and preferably 1 to 12 m, and a depth at least equal to 0.02 m and at most equal to 1.0 m to be formed such that the projected surface area of the dimples is at least equal to 30% of the surface area of the treatment region.

A skiving cutter includes a cutting edge portion in which a tooth trace extends in a direction inclined with respect to an axis of a base. The cutting edge portion is segmented into a plurality of segmented cutting edges by cutting edge grooves extending in a direction intersecting the tooth trace. One of the plurality of segmented cutting edges forms a reference cutting edge. Among the plurality of segmented cutting edges constituting the cutting edge portion, the reference cutting edge has the largest axis-cutting edge distance which is a distance from the axis to the outer circumferential cutting edge of the segmented cutting edge, and the remaining one or more segmented cutting edges have gradually smaller axis-cutting edge distances as a distance from the reference cutting edge to each of the remaining cutting edges increases. A helix angle is different according to positions of the plurality of segmented cutting edges.

A skiving cutter includes a cutting edge portion in which a tooth trace extends in a direction inclined with respect to an axis of a base. The cutting edge portion is segmented into a plurality of segmented cutting edges by cutting edge grooves extending in a direction intersecting the tooth trace. One of the plurality of segmented cutting edges forms a reference cutting edge. Among the plurality of segmented cutting edges constituting the cutting edge portion, the reference cutting edge has the largest axis-cutting edge distance which is a distance from the axis to the outer circumferential cutting edge of the segmented cutting edge, and the remaining one or more segmented cutting edges have gradually smaller axis-cutting edge distances as a distance from the reference cutting edge to each of the remaining cutting edges increases. A helix angle is different according to positions of the plurality of segmented cutting edges.