Utilization of laser beam oscillation to enhance the process efficiency for deep-penetration welding in aluminum

Laser beam remote welding is an established process in modern production plants. For instance, remote welding is used as a fast joining technology with rather large structural welds in car body manufacturing. Besides the advantages, such as noncontact machining and low process times, laser beam processing is also characterized by a low efficiency in contrast to other joining technologies. Therefore, this research has drawn attention to the improvement of the process efficiency for laser beam welding of the aluminum alloy AlMgSi1. The experiments were performed using a high power diode laser with a beam converter. The used scanning unit allowed a lateral beam oscillation perpendicular to the feed direction. Thereby, a new process was developed on the basis of high frequent beam oscillation. Hence, the sinusoidal beam oscillation enabled a defined heat input, whereas the laser beam was accelerated and the molten pool was widened. As a consequence, the process design leads to a significant preheating of the process zone, which contributes to a reduction in the deep-penetration welding threshold. Accordingly, low laser power is necessary to generate comparably large molten pools by means of laser beam oscillation. Correlating the amount of molten material with the deposited laser power, the results clearly show an increased process efficiency for the deep-penetration welding regime.