Spatter reduced high speed welding with disk lasers

Due to their numerous advantages in system technology, especially fiber optic beam delivery, solid state lasers have become state of the art for welding. Even so the obstacle of the so called “spatter regime” has been waiting for an industrial solution in order to gain high productivity. In general the spatter regime occurs in a distinct welding speed range. With deep penetration welding applications like in power train the spatter regime shows up at welding speeds of 5 to 6 m/min. Beyond 6 m/min the mass loss due to weld spatter reaches a level resulting in undercuts of the weld seam and potentially internal porosity, both of which reduce the mechanical strength properties of the part. Moreover, if spatter particles are present or dislodged when welded parts are being assembled, the gear box itself may incur in service damage. This report presents recent results addressing this problem and demonstrates significantly reduced spatter when welding at high speed, which today has only been achievable with CO2 laser beam welding. This new process approach is based on applying the disk laser with a special new beam forming method. The welding speed can be increased significantly and the energy efficiency of the process can be reduced dramatically.