Product Code: PIC06_M107

Laser Beam Micro-Welding with Single Mode Fibre Lasers
Authors:
Florian Wagner, BIAS Bremer Institut Fuer Angewandte Strahltechnik; Bremen Germany
Harald Kohn, BIAS; Germany
Presented at PICALO 2006

Single mode fibre lasers enable the welding of thin sheet materials. Although laser power is comparably low, the excellent beam quality of M2 < 1,1 provides intensities sufficient for keyhole welding. Especially for micro-fabrication, it is now possible to weld at considerable processing speed of 100 m/min and more, whilst heat input and thus distortion is minimized. Moreover, the weld pool and thus weld geometry is very narrow, consequently reducing the risk of weld imperfections due to weld shrinkage. Within the framework of this paper, the topic of keyhole welding of thin steel and aluminium sheets is addressed. Based on fundamental studies concerning welding speed and welding depth relations vs. power and energy density for various base materials, the potentials for low distortion and high speed processing are assessed. Finally, investigations for preventing humping at high processing speeds are presented on thin sheet materials.