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.

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 coated tool may include a base member and a coating layer. The coating layer may include a plurality of first AlTi layers indicated by Al.sub.1-x1Ti.sub.x1 and a plurality of second AlTi layers indicated by Al.sub.1-x2Ti.sub.x2. The coating layer may have alternating first AlTi layers and second AlTi layers, i.e. one upon another in a direction away from the base member, and x1 may be larger than x2. The plurality of first AlTi layers may include a first region having two or more adjacent first AlTi layers, where a first AlTi layer of the two or more adjacent first AlTi layers is located farther away from the base member and is smaller in thickness than a first AlTi layer of the two or more adjacent first AlTi layers located closer to the base member.

A coated tool according to the present disclosure includes a base member and a coating layer located on the base member. The coating layer includes a first peak located in a range of 0° to 90° and a second peak located at a higher angle side than the first peak in a distribution of X-ray intensity indicated at α axis of a pole figure, the X-ray intensity regarding a plane of the cubic crystal. The coating layer further includes a valley part between the first peak and the second peak, and the valley part includes the X-ray intensity smaller than the X-ray intensity at each of the first peak and the second peak.

A coated tool according to the present disclosure includes a base member and a coating layer located on the base member. The coating layer includes a first peak located in a range of 15° to 30° and a second peak located in a range of 60° to 75° in a distribution of X-ray intensity indicated at a axis of a pole figure, the X-ray intensity regarding a plane of the cubic crystal. The coating layer includes a valley part between the first peak and the second peak, and the valley part includes the X-ray intensity smaller than the X-ray intensity at each of the first peak and the second peak. The X-ray intensity at the first peak is 0.7 times or greater of the X-ray intensity at the second peak.

In one aspect, cutting tools are described herein comprising wear resistant coatings employing one or more refractory layers of polycrystalline α-Al.sub.2O.sub.3. Briefly, a coated cutting tool described herein comprises a substrate, and a coating adhered to the substrate, the coating comprising a layer of polycrystalline α-Al.sub.2O.sub.3 deposited by chemical vapor deposition (CVD), wherein at least 5% of all grain boundaries in the polycrystalline α-Al.sub.2O.sub.3 layer have a misorientation angle less than 15 degrees as determined using a field-emission scanning electron microscope (FESEM) and an electron backscatter diffraction (EBSD) detector.

A textured surface in an outer surface of a tool holding section of a tool holder for increasing a surface area of the outer surface for dissipating heat from the tool holding section. The textured surface can comprise grooves around the outer surface of the tool holding section with a height and a width. Notches can be provided in sides of the grooves to further increase the surface area of the outer surface for dissipating heat from the tool holding section.

A coated tool includes a base and a coating layer on the base. The coating layer includes a first layer including Al.sub.2O.sub.3 particles, and a second layer on the first layer. The second layer includes, sequentially from the base, a first film, a second film in contact with the first film, and a third film in contact with the second film. The first to third films individually include Ti. The first film, the second film and the third film individually include at least one kind selected from C and N. The coated tool satisfies a relationship of a first N content>a third N content>a second N content, in which the first N content is an N content in the first film, the second N content is an N content in the second film, and the third N content is an N content in the third film.

A coated tool includes a base and a coating film on the base. The coating film includes an Al.sub.2O.sub.3 layer, and a surface layer on the Al.sub.2O.sub.3 layer. The surface layer has a first erosion rate of 0.1 μm/min or less. The first erosion rate is obtained from measurement by causing a liquid A, in which 3 mass % of amorphous Al.sub.2O.sub.3 particles having a mean particle diameter of 1.1-1.3 μm is dispersed in purified water, to collide with the surface layer. The surface layer has a second erosion rate of 2.0 μm/min or more. The second erosion rate is obtained from measurement by causing a liquid B, in which 3 mass % of spherical Al.sub.2O.sub.3 particles having a mean particle diameter of 2.8-3.2 μm is dispersed in purified water, to collide with the surface layer.

A coated cutting tool which has, on a surface of a substrate, a layer A of a face-centered cubic lattice structure which is a nitride or carbonitride containing 50 atom % or more of Al, 20 atom % or more of Cr, 85 atom % or more of Al and Cr, and 4 atom % or more and 15 atom % or less of Si, and a layer B provided on the layer A. The layer B is a nitride or carbon nitride which contains 70 atom % or more and 90 atom % or less of Ti, 5 atom % or more and 20 atom % or less of Si, and 1 atom % or more and 10 atom % or less of Nb or Cr in terms of a total amount of metal (including metalloid) elements, and has the face-centered cubic lattice structure.