Laser welding in a vacuum—One process for micro to macro applications

Laser beam welding in a vacuum presents a promising alternative to conventional laser and electron beam welding by combining high penetration depths, excellent seam quality, and reduced energy requirements. This paper introduces a mobile vacuum (MoVac) welding system, which enables localized pressure reduction directly at the weld zone, making vacuum welding viable for large-scale industrial applications. The process was applied to 30 mm thick S355ML steel plates with butt joint configurations and varying gap widths. The study focuses on gap-bridging capabilities using a filler wire and different linear beam oscillation parameters. Results show that linear oscillation enhances energy distribution at joint flanks, improving gap bridging and weld quality. For gaps up to 0.5 mm, high-quality welds without defects were achieved with 1.6 mm amplitude at 25 Hz oscillation. However, increasing the gap to 1.0 mm introduces stability issues due to leakage into the vacuum zone. Experimental optimization and theoretical considerations underline the process’s potential for both microscale and macroscale applications, especially in mobility, energy, and structural component industries. The findings confirm the MoVac system’s suitability for robust, high-quality, and efficient welding under vacuum conditions with promising scalability.