Laser welding with oscillating beam
Nearly simultaneously with the introduction of laser technology into the welding practise, scientists aimed at the extension of welding application techniques. Examples: pulsed laser systems, multi-beam technique and numerous variations of laser hybrid welding.
In addition to these proven procedures, investigations work on process manipulations, which use optical scanner systems. One characteristic feature of this technology is a periodical oscillation of the beam via moving mirrors, integrated in the beam path between laser and workpiece ( Fig.1, left). Thus different oscillation patterns can be generated (Fig. 1, right), which enable to influence directly the energy deposition.
Fig. 1:Principle for the realization of the beam oscillation ( left) as well as examples of possible beam oscillations (right).
Due to the overlap of feed rate and oscillatory motions, complex conditions for the energy deposition result. The resulting correlations between the single influences are not often directly transparent. This is the reason why the recent researches at the LOT concentrate on a comprehensive theoretical description of these process variations and the development of corresponding simulation programs. Furthermore, the possibilities of the laser welding with oscillating beam are investigated by means of practical welding tests. Here, such joining tasks come to the fore, which are very delicate for conventional techniques, e.g. the welding of galvanized sheets in gapless lap joints, the high speed welding, the joining of crack- and pore susceptible material classes as well as the welding with gap.
Literatur:
[1] A. Mahrle, E. Beyer (2007), Mathematical Description of the Transient Energy Deposition in Laser Materials Processing with Forced Beam Oscillations, 20th Meeting on Mathematical Modelling of Materials Processing with Lasers, 17-19/01/2007, Igls/Innsbruck (A).