The present invention relates to a combustion chamber tile of a gas turbine, where the combustion chamber tile has a plurality of effusion cooling holes and a mixing air hole provided as a flow-guiding element (chute) and projecting over the surface of the combustion chamber tile, characterized in that on the side of the mixing air hole facing away from a flow along the combustion chamber tile at least one supporting element is arranged on the combustion chamber tile and on the mixing air hole. It also relates to a method for its manufacture.

The present invention relates to a combustion chamber tile of a gas turbine, where the combustion chamber tile has a plurality of effusion cooling holes and a mixing air hole provided as a flow-guiding element (chute) and projecting over the surface of the combustion chamber tile, characterized in that on the side of the mixing air hole facing away from a flow along the combustion chamber tile at least one supporting element is arranged on the combustion chamber tile and on the mixing air hole. It also relates to a method for its manufacture.

The present invention provides an entry sheet for drilling excellent in hole position accuracy compared with the conventional entry sheet for drilling. Such an entry sheet for drilling is an entry sheet for drilling comprising metallic support foil and a layer comprising a resin composition formed on at least one surface of the metallic support foil, in which the resin composition contains a resin and 70 parts by mass to 130 parts by mass of molybdenum disulfide based on 100 parts by mass of the resin, and the layer comprising the resin composition has a thickness in a range from 0.02 to 0.3 mm.

The present invention provides an entry sheet for drilling excellent in hole position accuracy compared with the conventional entry sheet for drilling. Such an entry sheet for drilling is an entry sheet for drilling comprising metallic support foil and a layer comprising a resin composition formed on at least one surface of the metallic support foil, in which the resin composition contains a resin and 70 parts by mass to 130 parts by mass of molybdenum disulfide based on 100 parts by mass of the resin, and the layer comprising the resin composition has a thickness in a range from 0.02 to 0.3 mm.

A method includes applying a force to elastically deform at least a portion of a superalloy turbine blade from a relaxed, initial position to an elastically deformed position. The at least a portion of the superalloy turbine blade has a curvature in the elastically deformed position not present in the relaxed, initial position. A hole is drilled generally span-wise through the at least a portion of the superalloy turbine blade in the elastically deformed position, and when the force is released, the superalloy turbine blade returns to the relaxed, initial position and the hole takes on a hole curvature within the at least a portion of the superalloy turbine blade.

An entry sheet for drilling comprising: a metallic foil; and a layer of a resin composition on at least one surface of the metallic foil, the resin composition comprising a polyolefin resin (A) and a water-soluble resin (B), wherein a content of the polyolefin resin (A) is 25 parts by mass or more and 50 parts by mass or less based on 100 parts by mass of the total of the polyolefin resin (A) and the water-soluble resin (B), a content of the water-soluble resin (B) is 50 parts by mass or more and 75 parts by mass or less based on 100 parts by mass of the total of the polyolefin resin (A) and the water-soluble resin (B), and the water-soluble resin (B) comprises a high-molecular-weight water-soluble resin (B-1) having a weight average molecular weight of 210.sup.5 or higher and 1.510.sup.6 or lower.

An entry sheet for drilling comprising: a metallic foil; and a layer of a resin composition on at least one surface of the metallic foil, the resin composition comprising a polyolefin resin (A) and a water-soluble resin (B), wherein a content of the polyolefin resin (A) is 25 parts by mass or more and 50 parts by mass or less based on 100 parts by mass of the total of the polyolefin resin (A) and the water-soluble resin (B), a content of the water-soluble resin (B) is 50 parts by mass or more and 75 parts by mass or less based on 100 parts by mass of the total of the polyolefin resin (A) and the water-soluble resin (B), and the water-soluble resin (B) comprises a high-molecular-weight water-soluble resin (B-1) having a weight average molecular weight of 210.sup.5 or higher and 1.510.sup.6 or lower.

A drill bit for use in forming holes in a printed circuit board (PCB) is disclosed. The drill bit includes a drill bit body having: a drill bit tip at a first end of the drill bit body; a flute winding about the drill bit body in a helix, wherein a helix angle of the flute is between 44 and 46 degrees in the vicinity of the first end and increases with increasing distance from the first end to between 49 and 51 degrees; and a land width of between 0.08 and 0.1 millimeters.

A drill bit for use in forming holes in a printed circuit board (PCB) is disclosed. The drill bit includes a drill bit body having: a drill bit tip at a first end of the drill bit body; a flute winding about the drill bit body in a helix, wherein a helix angle of the flute is between 44 and 46 degrees in the vicinity of the first end and increases with increasing distance from the first end to between 49 and 51 degrees; and a land width of between 0.08 and 0.1 millimeters.

Disclosed is a drilling method for PCBs with high hole position precision, comprising: step 1 of fixing a PCB on a workbench; step 2 of pre-drilling a to-be-drilled portion of the PCB by using a short-blade drilling tool; and step 3 of deeply drilling the to-be-drilled portion which has been machined in step 2 by using along-blade drilling tool. The PCB is fixed in step 1 to prevent the PCB from moving during drilling which otherwise would affect the drilling precision; the to-be-drilled portion of the PCB is pre-drilled by using a short-blade drilling tool in step 2, and the short-blade drilling tool has a higher rigidity than along-blade drilling tool and thus will not easily slide at the moment of contacting the surface of the PCB; and the to-be-drilled portion which has been machined in step 2 is deep drilled by using the long-blade drilling tool in step 3, and the long-blade drilling tool has reduced sliding upon entry, thus guaranteeing the entry alignment of the long-blade drilling tool in the case of deep drilling, so that the drilled hole meets the requirement of high hole position precision for PCBs.