LZH, partners develop laser welding process for joining 3-D structures of steel, aluminum

Laser Zentrum Hannover e.V. (LZH), within the LaserLeichter project, has developed a laser welding process for quick, safe joining of 3-D structures made of steel and aluminum, such as lightweight steel-aluminum composite components used in automobiles.

To optimize the joining of mixed compounds for series production in the automotive industry, the scientists at LZH have developed processes for joining two- and three-sheet metal joints with high welding speeds of up to 23 FPM. The basis for the remote laser beam welding process is a 3-D scanner optic, newly developed by TRUMPF Laser GmbH. With this optic, complex, 3-D seam geometries are possible even on large structures. Therefore, the process is suitable for car body construction and can be used as an alternative to complex robotic movements.

The weld joint achieves a shear tensile strength of about 67 percent of the aluminum alloy. The parallel arrangement of the three welds can increase this percentage to about 95.

The process was developed for battery cases of electric cars, seat structures, and car body parts. Volkswagen AG has tested the validation components for car body applications. The joined mixed compounds have an advantageous crash behavior, since the joining partners remain safely connected.

LZH, VW, and partners inpro Innovationsgesellschaft für fortgeschrittene Produktionssysteme in der Fahrzeugindustrie mbH, Precitec GmbH & Co. KG, MATFEM Partnerschaft Dr. Gese & Oberhofer, Lunovo GmbH, Scherdel Marienberg GmbH, InfraTec GmbH, Brandenburgische Technische Universität Cottbus-Senftenberg, and the Fraunhofer-Institut für Werkstoff- und Strahltechnik IWS worked together under the coordination of Robert Bosch GmbH. Associated partners were TRUMPF Laser GmbH, Astor Schneidwerkzeuge GmbH, ThyssenKrupp Steel Europe AG, Bond-Laminates GmbH, and Hydro Extrusion Offenburg GmbH. The LaserLeichter project was funded by the Federal Ministry of Education and Research.