A board drilling apparatus, drill bit, and method for board drilling apparatus to drill a board. The board drilling apparatus (4) is configured to drill a board comprising at least a target conductive layer (13), an insulation layer, and a hole (3) covered with conductive material through at least part of the board in thickness, to remove at least part of the conductive material, the board drilling apparatus (4) comprising a drill bit (41) and a controller (43): the drill bit (41) comprising an insulation part (412) at least in center of end of the drill bit (41) and a conductive part (411) at least on edge of the end of the drill bit (41), arranged to enable only the insulation part (412) to be in touch with the conductive material of the hole (3) when the board drilling apparatus (4) is drilling the board, and arranged to enable the conductive part to get in touch with the target conductive layer (13) once the conductive material on the way to the target conductive layer (13) has just been removed; and the controller (43) configured to stop drilling when receiving an electrical signal occurred in response to the drill bit touching the target conductive layer of the board.

A surface-coated cutting tool comprises a tool substrate comprising a cBN sinter and a hard coating layer including a lower sublayer α and an upper sublayer β on the surface of the cutting edge; wherein α satisfies (Al.sub.1-xTi.sub.x)N (0.40≤x≤0.60); β satisfies (Al.sub.1-y-zTi.sub.yB.sub.z)N (0.40≤y≤0.60 and 0.01≤z≤0.10); in the sublayer β, the variation in the concentration of the B component is repeated; the average Bmaxav of the maxima in the concentration of the B component satisfies z<Bmaxav≤2.0×z, and the average Bminav of the minima in the concentration of the B component satisfies 0≤Bminav<z; and the average thickness tα of α and the average thickness tβ of β satisfy expression: 2.0≤<tβ/tα≤6.0; and the residual stress σ of the overall hard coating layer satisfies −2.0 GPa≤σ≤−0.5 GPa.

The present invention relates to a cutting tool consisting of a hard base material, such as cemented carbide, cermet, ceramic, and cubic boron nitride, and a hard coating film formed on the hard base material. In the cutting tool according to the present invention, the hard coating film, which is composed of a monolayer or multilayer structure, is formed on a base material, wherein the hard coating film comprises a layer composed of an oxide, wherein in the layer composed of an oxide, the oxygen content of an edge center of the cutting tool is higher than the oxygen content in an area distanced from the edge center by 50 μm or more.

A cutting insert is provided, comprising a top surface, a bottom surface, a plurality of side surfaces spanning therebetween, and a cutting edge formed at an intersection of the side surface and a forwardly-disposed portion of the top the surface. It further comprises a cooling cavity projecting into the insert, a top end thereof being disposed further forwardly than an open bottom end thereof. The cooling cavity defines at least one molding axis such that a solid element having the shape of the cooling cavity and completely inserted therein may be retracted intact therefrom along a linear path parallel to the molding axis. A circumscribing portion is formed on the side surfaces encircling the cutting insert. The circumscribing portion is formed parallel to the molding axis and has a non-zero height along its entire extent. The cutting insert does not extend beyond the circumscribing portion.

A coated tool in a non-limiting embodiment of the present disclosure includes a base and a coating film located on the base. The coated tool includes a first surface, a second surface adjacent to the first surface, and a cutting edge located on at least a part of a ridge part of the first surface and the second surface. The coating film includes an AlTiN film including Ti, Al and N. A first Al ratio and a second Al ratio are 0.7 or more. The first Al ratio is Al/(Al+Ti) at a point located 0.1 mm away from the cutting edge, and the second Al ratio is Al/(Al+Ti) at a point located 0.2 mm away from the cutting edge in the first surface. The second Al ratio is larger than the first Al ratio.

A coated tool in a non-limiting embodiment of the present disclosure includes a base and a coating film located on the base. The coated tool includes a first surface, a second surface adjacent to the first surface, and a cutting edge located on at least a part of a ridge part of the first surface and the second surface. The coating film includes an AlTiN film including Ti, Al and N. A first Al ratio and a second Al ratio are 0.7 or more. The first Al ratio is Al/(Al+Ti) at a point located 0.1 mm away from the cutting edge, and the second Al ratio is Al/(Al+Ti) at a point located 0.2 mm away from the cutting edge in the first surface. The second Al ratio is larger than the first Al ratio.

A coated cutting tool is provided which allows for satisfactory machining over a long period of time, particularly in the machining of difficult-to-machine materials with low thermal conductivity. The coated cutting tool includes a substrate and a coating layer formed on a surface of the substrate, wherein: at least one layer of the coating layer comprises a predetermined layer containing a compound having a composition represented by the formula: (Al.sub.XTi.sub.1-X)N [wherein x denotes an atomic ratio of the Al element based on a total of the Al element and the Ti element, and x satisfies 0.60≤x≤0.85]; a value of an orientation index TC (311) of a cubic (311) plane of the predetermined layer is from 2.5 or more to 4.2 or less; and an average thickness of the predetermined layer is from 1.0 μm or more to 12.0 μm or less.

A coated cutting tool, comprising: a substrate; and a coating layer formed on a surface of the substrate, wherein the coating layer includes a lower layer and an upper layer in this order from the substrate side toward the surface side of the coating layer, and the upper layer is formed on a surface of the lower layer, the lower layer contains a compound having a composition represented by (Al.sub.xTi.sub.1-x)N, an average thickness of the lower layer is 1.0 μm or more and 15.0 μm or less, the upper layer contains an α-Al.sub.2O.sub.3 layer containing α-Al.sub.2O.sub.3, an average thickness of the upper layer is 0.5 μm or more and 15.0 μm or less, and in the α-Al.sub.2O.sub.3 layer, a texture coefficient TC (1, 1, 6) of a (1, 1, 6) plane is 2.0 or more and 6.0 or less.

A diamond tool includes a diamond at least on a cutting edge including one or two or more diamond grains including a diamond phase composed of a diamond crystal structure and a graphite phase composed of a graphite crystal structure. When a ratio I.sub.π*/I.sub.σ* between an intensity of a π* peak derived from a π bond of carbon in the graphite phase and an intensity of a σ* peak derived from a σ bond of carbon in the graphite phase and a σ bond of carbon in the diamond phase is determined for the diamond grain by measuring an energy loss associated with excitation of K-shell electrons of carbon by electron energy loss spectroscopy, the ratio I.sub.π*/I.sub.σ* of the diamond grain on a surface of the cutting edge is 0.1 to 2 and a ratio I.sub.π*/I.sub.σ* of the diamond grain at a depth position of 0.5 μm from the surface of the cutting edge is 0.001 to 0.1.

A coated tool of the present invention includes a base material and a hard coating film on the base material. The hard coating film is a nitride or carbonitride containing aluminum (Al) of 65 atomic % or more 90 atomic % or less, titanium (Ti) of 10 atomic % or more 35 atomic % or less, a total of aluminum (Al) and titanium (Ti) of 85 atomic % or more, and argon (Ar) of 0.20 atomic % or less. The hard coating film satisfies a relationship of Ih×100/Is≤12 when a peak intensity of a (010) plane of AlN of a hexagonal close-packed structure is Ih and a sum of peak intensities due to predetermined nine crystal planes of TiN and AlN is Is in an intensity profile obtained from a selected area diffraction pattern of a transmission electron microscope.