Abstract: In the laser drilling of a hole through a wall of a gas turbine blade into a cavity within the blade there is provided an injectable PTFE substitute for injection into the cavity before laser drilling. The PTFE substitute prevents strike-through of laser light to the opposite wall of the cavity. The PTFE substitute used is fluorinated ethylene propylene or a copolymer having a PTFE backbone and fully fluorinated alkoxy side groups.

Abstract: A variety of configurations for convergent-divergent film cooling holes are disclosed, together with the hole drilling methods necessary to achieve the configurations.

Abstract: PTFE-loaded wax is used in the laser drilling of holes in hollow turbine blades to prevent strike-through of the beam to an opposite wall of a cavity in the blade. The PTFE-loaded wax is poured or injected in molten form into the cavity prior to laser-drilling, and is subsequently removed by steaming.

Abstract: An apparatus for drilling a shaped hole in a workpiece by means of a laser beam emanating from a laser source, includes (a) means for directing the beam onto the workpiece, (b) means for controlling the angle of the beam striking the workpiece relative to the axis of the hole, and, (c) means for controlling the distance between the intersection of the beam with the surface of the workpiece and the axis of the hole, so that the combination of the means for controlling the angle and the means for controlling the distance enables a shaped hole to be drilled in the workpiece by the laser beam. The apparatus also includes means for rotating the direction of the beam about the axis of the hole so as to describe at least part of the curved surface of a one that has its vertex on or within the body of the workpiece.

Abstract: A variety of configurations for convergent-divergent film cooling holes are disclosed, together with the hole drilling methods necessary to achieve the configurations.