Method and apparatus for laser trepanning

An improved method and apparatus for laser trepanning a passage through a workpiece, gas turbine engine component or the like includes the method steps of: providing a linearly polarized beam of laser energy; focusing the laser beam on a selected location on the component; moving one of the laser beam or the workpiece relative to one another along a first selected trepanning path and along a second selected trepanning path, which is substantially opposite in direction to the first selected path, to compensate for the linear polarization of the laser beam and to reduce the processing time. The steps of moving one of the laser beam or the workpiece along the first and second trepanning paths are repeated until a passage is cut to a desired depth into the surface of the component or the passage is cut entirely through the component. An apparatus for accomplishing the method of the present invention includes a laser system for generating a linearly polarized beam of laser energy and a manipulator arrangement for moving one of the laser system or the component relative to one another. The apparatus further includes a computer controller which is programmed to move either the laser system or the component along the first and second selected trepanning paths.