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Powerful features for LBW including theoretical aspects


Duley, W.; Shibata, K.; Poprawe, R. ; Laser Institute of America -LIA-:
Laser Materials Processing Conference 1996. Proceedings : October 14-17, 1996, Radisson Plaza Hotel at Town Center, Detroit, Michigan, USA
Orlando, Fla.: LIA, 1996 (LIA 81)
ISBN: 0-912035-54-4
International Congress on Applications of Lasers and Electro Optics (ICALEO) <1996, Detroit/Mich.>
Conference Paper
Fraunhofer ILT ()
laser beam welding

The performance of laser beam welding strongly depends on the education of the machine operator. The development of processing parameters for each machine installation and trouble-shooting are time and cost intensive. CALas, a fast simulation software of the laser beam welding process is presented. The physical basis and its appearance in the numerical algorithm is discussed. The model considers the fundamental physical processes, absorption of laser radiation at the keyhole surface including multiple reflections, heat conduction in liquid and solid phases, melt flow and gas flow, absorption of laser radiation in the vapor phase and heat conduction in the plasma volume. Integral formulations are used in order to decrease the calculation time and to preserve the most important features of the experimental results. The results are compared with off-line measurements of the welding depth, the seam width and the cooling time. The welding process is far from its stationary state and experim entally observed quantities are intrinsically time dependent. Therefore, already the setup of a stationary model requires some knowledge about the dynamics. The fundamental physical processes are ordered by their typical time-scales. On-line measurement of plasma emission and numerical simulation of an evolving capillary are presented.