Patent ID: 7521648
Filing Date: 2009-04-21
Classification: B23K

Abstract:
1. A method of laser machining an orifice in a workpiece by a laser system having an optical focusing assembly, the method comprising: evaluating an orifice formed via a focusing spot size of a first effective area formed by transmission of a laser beam through the optical focusing assembly to the work piece at a rated maximum power of the laser system for splatters, recasts or heat affected zone proximate the orifice; and reducing a power density of the focusing spot size via an overlay between the laser beam and the optical focusing assembly to a suitable power density sufficient to machine an orifice while maintaining the first effective area so that splatters, recasts or heat affected zone proximate the orifice is reduced; wherein the overlay comprises at least one optically neutral lens provided with a light blocking polygon within a perimeter of the laser beam, such that the light blocking polygon blocks a portion of the laser beam and permits a remainder of the laser beam to pass through the lens to the optical focusing assembly.