Coherent, Inc.
LASER WELDING METHOD

Abstract:

A method for laser keyhole welding is disclosed to weld two pieces together made of a metal alloy. The method independently adjusts power in a focused center beam and power in a concentric focused annular beam. At the termination of a weld, the power of the annular beam is reduced, motion of the focused beams is stopped, the power of the center beam is increased, and the power of both beams is initially ramped down rapidly and then ramped down slowly. Increasing the power of the center beam equalizes the temperature of both pieces prior to solidification and cooling at the termination of the weld. An additional pulse of power may be applied to prevent the formation of defects or to erase any defects.