Methods and apparatus for forming an aperture in a composite component are provided. For example, a method for forming an aperture in a ceramic matrix composite (CMC) component comprises, based on a final dimension of the aperture, selecting a tool having a tool size and a cutting surface; selecting an angle at which to cut the component with the tool; cutting a back surface of the component with the tool, the cutting surface positioned at the angle; repositioning the tool relative to the component; and cutting the aperture through to its final dimension. The tool may be a core drill with a diameter within a range of 60% to 90% of the aperture final dimension. The angle may be within a range of 10° to 60° with respect to the back surface. The aperture may be cut through to its final dimension from a front surface of the component.

Certain embodiments of the present disclosure provide an acoustic inlet barrel of an engine. The acoustic inlet barrel may include an inner barrel configured to provide a boundary for directing airflow through the engine. The inner barrel may include an inner face sheet separated from an outer face sheet by an acoustic core. The inner barrel may include a plurality of elongated, non-circular perforations formed through the inner face sheet.

A coated tool, such as a rotating, cutting tool, includes a tool body and a multilayer wear protection coating system. The wear protection system coats a functional surface of the tool body that is subject to wear and includes a first undoped diamond layer and a second undoped diamond layer disposed over the first undoped diamond layer. The first undoped diamond layer is electrically conductive and exhibits grain boundary conductivity from delocalized electrons. The second undoped diamond layer is electrically insulating. The first undoped diamond layer is 4-20 microns thick and is made with diamond grains whose size ranges from 4-10 nm. The first and second diamond layers are applied by chemical vapor deposition (CVD) using a hot-wire method. The wear protection system also includes an additional undoped diamond layer that is electrically insulating and is disposed between the functional surface of the tool body and the first diamond layer.

According to one implementation, a drill has at least one cutting edge. A projected shape of a passing area of a ridgeline of the at least one cutting edge when the at least one cutting edge is rotated around a tool axis becomes a line-symmetric and discontinuous line along a parabola, two parabolas, an ellipse or two ellipses. The projected shape is drawn on a projection plane parallel to the tool axis.

A composite polycrystal contains polycrystalline diamond formed of diamond grains that are directly bonded mutually, and non-diamond carbon dispersed in the polycrystalline diamond, and has a concentration of contained hydrogen of greater than 1000 ppm and less than or equal to 20000 ppm.

A tool system for machining a workpiece is provided having a cylinder-shaped retaining shank that has a cutting head holder on an end surface facing the workpiece, a drive mount on an end surface facing the drive, a cutting head having at least one cutting edge, a cutting head hub corresponding to the cutting head holder on the retaining shank, a tool coupling with a tool interface, and a coupling hub corresponding to the drive mount. The coupling hub or the cutting head hub have elevated areas, with contact surfaces, distributed in circumferential and longitudinal directions of the coupling hub or the cutting head hub. The contact surfaces make contact on support surfaces on the drive mount or on the cutting head holder on the retaining shank. The drive mount or the cutting head holder is permanently connected to the coupling hub or the cutting head hub by a joining material in intermediate spaces between the elevations.

A method to form a hole in a ceramic matrix composite component may be provided. A monolithic rod may be inserted into a porous ceramic preform. The ceramic preform may be formed into a ceramic matrix composite body that includes the monolithic rod. A portion of the monolithic rod may be removed, leaving a remaining portion in the ceramic matrix composite body. The remaining portion may include walls that define the opening in the ceramic matrix composite body. Alternatively or in addition, a ceramic matrix composite component may be provided. The ceramic matrix composite component may comprise a ceramic matrix composite body that includes a portion of a monolithic rod. The portion of the monolithic rod forms a lining around a hole passing partly or entirely through a length of the monolithic rod.

Described herein is a first method of forming a hole in a workpiece, having a first surface and a second surface opposite the first surface. The method includes forming a first hole, having a first diameter, in the workpiece by passing a first cutter through the workpiece from the first surface to the second surface. Additionally, the method includes forming a chamfer in the second surface of the workpiece concentric with the first hole using a second cutter. The chamfer has a second diameter larger than the first diameter. The method further includes forming a second hole, having a third diameter larger than the first diameter, in the workpiece concentric with the first hole by passing a third cutter through the workpiece from the first surface to the second surface.

A clamp comprises first and second jaws that provide contact surfaces. The first jaw is elongated and has a longitudinal bore. The jaws are transversely hinged to maintain bore perpendicularity.

According to one implementation, a drill includes the first cutting edges, the second cutting edges and a deflection reducer. The first cutting edges drill a prepared hole to a workpiece. The first cutting edges are formed in a tip side of the drill. The first point angle and each first relief angle of the first cutting edges continuously or intermittently decrease from the tip side toward a rear end side of the drill. The second cutting edges finish the prepared hole. The second cutting edges are formed at positions away in the rear end side from the first cutting edges. The second cutting edges have the second relief angles at a maximum diameter position. The deflection reducer reduces deflection of the second cutting edges by being inserted into the prepared hole. The deflection reducer is formed between the first cutting edges and the second cutting edges.