Influence of dynamic beam shaping on the geometry of the keyhole during laser beam welding

• Published in: Procedia CIRP Vol. 111; pp. 448 - 452
• Main Authors: Wagner, Jonas, Heider, Andreas, Ramsayer, Reiner, Weber, Rudolf, Faure, Frauke, Leis, Artur, Armon, Nina, Susid, Roey, Tsiony, Oded, Shekel, Eyal, Graf, Thomas
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 2022
• Subjects: beam shaping; coherent beam combining; keyhole geometry; laser welding; keyhole geometry; laser welding; coherent beam combining; beam shaping
• ISSN: 2212-8271; 2212-8271
• DOI: 10.1016/j.procir.2022.08.185

In deep penetration laser welding the shape of the keyhole is one of the determining variables for the energy input for each material and therefore has a significant influence on the resulting weld seam. A variation of the intensity distribution on the sample's surface changes the shape of the keyhole as well as the distribution of the locally absorbed irradiance within the keyhole. Coherent beam combining through optical phased arrays enables an almost arbitrary variation of the local intensity distribution of the laser beam as well as switching between different intensity distributions at high frequencies. The impact of dynamic beam shaping on the longitudinal and transversal extension of the keyhole was analyzed by means of streak images. Subsequently the frequency of changes in the extent were determined by the application of a fast Fourier transform on the grayscale values of the streak images. The results indicate a high correlation between the temporal variation of the intensity and the geometry of the keyhole.