The present invention relates to a method for the production of drill holes in difficult to machine materials, in which a removal of material takes place in order to produce a drill hole by electrochemical erosion of material by an electrode that is moved in the longitudinal direction of the drill hole being produced in the direction onto the material to be processed at a feed rate, wherein the drilling has at least two steps, wherein, in the first step, the electrochemical processing takes place, and wherein, in a second step, the further processing of the drill hole to the final diameter takes place by machining processing or by erosion or by an electrochemical processing.

The present invention relates to a method for the production of drill holes in difficult to machine materials, in which a removal of material takes place in order to produce a drill hole by electrochemical erosion of material by an electrode that is moved in the longitudinal direction of the drill hole being produced in the direction onto the material to be processed at a feed rate, wherein the drilling has at least two steps, wherein, in the first step, the electrochemical processing takes place, and wherein, in a second step, the further processing of the drill hole to the final diameter takes place by machining processing or by erosion or by an electrochemical processing.

A method of polishing a surface of an object disposed within a gas chamber is provided. The method includes filling the gas chamber with a discharging medium to a predefined pressure, applying a voltage between an electrode and the surface, calibrating a height of the electrode relative to the surface so as to establish electrical breakdown threshold criteria, and scanning the electrode with respect to the surface so as to sequentially position the electrode over a plurality of locations on the surface, each location characterized by a surface error. When a respective location in the plurality of locations has a surface error that meets the electrical breakdown threshold criteria, electrical breakdown occurs, whereby the electrical breakdown results in a discharging pulse that polishes the surface.

A method of polishing a surface of an object disposed within a gas chamber is provided. The method includes filling the gas chamber with a discharging medium to a predefined pressure, applying a voltage between an electrode and the surface, calibrating a height of the electrode relative to the surface so as to establish electrical breakdown threshold criteria, and scanning the electrode with respect to the surface so as to sequentially position the electrode over a plurality of locations on the surface, each location characterized by a surface error. When a respective location in the plurality of locations has a surface error that meets the electrical breakdown threshold criteria, electrical breakdown occurs, whereby the electrical breakdown results in a discharging pulse that polishes the surface.

To provide a turbine blade, a manufacturing method for a turbine blade, and a gas turbine. In the turbine blade including a cooling passage provided along a blade height direction, the cooling passage includes: a first cooling hole including one end opening toward a front end, and having an inner diameter that is constant along the blade height direction; and a second cooling hole including one end communicating with the other end of the first cooling hole without a level difference, and having an inner diameter that is increased toward a base end. A length from the one end of the first cooling hole to a position where the first cooling hole and the second cooling hole are communicated with is 40% to 60% of a length from the one end of the first cooling hole to a gas path surface on the base end.

According to one embodiment, a tungsten wire includes a tungsten alloy containing rhenium. The tungsten wire includes a protrusion peak density (Spd) of 7000 or more and 11000 or less as a surface roughness parameter.

According to one embodiment, a tungsten wire includes a tungsten alloy containing rhenium. The tungsten wire includes a protrusion peak density (Spd) of 7000 or more and 11000 or less as a surface roughness parameter.

The present invention is directed to a current feeding device for the supply of electrical current to a wire electrode traveling in an electro-erosion machine during the machining operation. The current feeding device comprising: a rotary electrically conductive body which is in contact with the wire electrode; at least one bearing for supporting the rotary electrically conductive body at one side; and a brush for electrically contacting the rotary electrically conductive body and for supporting the rotary electrically conductive body at the other side of the body and opposite side to the bearing. The brush is at the rotary axis of the rotary electrically conductive body.

Methods and devices for etching patterns on interior surfaces of hollow objects are described. The method may include preparation of the interior surface of the object, such as pre-cleaning, and coating the interior surface of the object. A pattern may then be generated on the interior surface of the object by any of mechanical or manual scribing and peeling, laser ablation, or photoresist coating and laser exposure, development and hardening. The pattern is then etched using chemical etchants, and finished to remove remaining coating, provide surface passivation and/or protectant application. Mechanical and laser devices which may facilitate pattern generation are also described.

Methods and devices for etching patterns on interior surfaces of hollow objects are described. The method may include preparation of the interior surface of the object, such as pre-cleaning, and coating the interior surface of the object. A pattern may then be generated on the interior surface of the object by any of mechanical or manual scribing and peeling, laser ablation, or photoresist coating and laser exposure, development and hardening. The pattern is then etched using chemical etchants, and finished to remove remaining coating, provide surface passivation and/or protectant application. Mechanical and laser devices which may facilitate pattern generation are also described.