LBW of high stiffness light weight structures generated by scanned fiber laser beams

Laser beam welded (LBW) slot-tab joints of thin sheet metal structures are characterized by high stiffness, low weight and simple alignment due to the interlocking sheet components. Those properties make the slot-tab joint reasonable for lightweight structures. Welding of slot-tab joints is more challenging than typical sheet metal welding as gaps are necessary in the interlocking regions to reduce insertion problems. A larger weld-pool cannot be used because the molten material will drop out between the thin sheets. In this work an application of laser cutting as well as the combination of high beam quality fiber lasers with high speed laser scanners extended the technological flexibility. Thus it was possible to manufacture the parts precisely, the bridging of gaps could be enhanced and the fusion zone width was increased while the typically high welding speed reduces heat input.