Patent ID: 7019257

Claim:
A method of laser trepan drilling diffuser type holes in a workpiece having a wall defining an internal cavity, the method comprising: laser drilling a hole of substantially constant cross-section through a wall of the workpiece, the laser drilling using a beam of a laser; and directing the beam of the laser such that the beam follows a path on at least one side of the hole to drill a diffuser section on at least a beam entry side of the hole with the beam exiting the hole substantially without interference with a remaining non-diffuser part of the hole, wherein the diffuser section is cut with a generally elongate opening on the beam entry side of the hole, with the beam being inclined with respect to a longitudinal axis of the hole, and with the beam being inclined with respect to an elongate axis of the opening being formed on the beam entry side of the wall such that the beam is directed substantially wholly into an interior of the hole as the beam passes therethrough.