Copper joints with different sheet thicknesses are widely used in electrical systems, power electronics, automotive applications, and industrial equipment. For these components, both the electrical resistance of the joint and its mechanical strength are critical, as they directly influence efficiency, thermal losses, and long-term reliability. Laser beam welding with infrared laser sources is a promising method for producing copper joints in the thickness range of approximately 0.3 mm to 2.0 mm. However, the relationship between weld seam geometry, resulting connection width, and the electrical and mechanical performance of the joint is still not fully understood.

In this study, the influence of different weld seam geometries on the connection width, electrical resistance, and tensile strength of laser beam welded copper joints is investigated. Experiments were conducted on pure copper sheets with thicknesses of 0.5 mm and 1.0 mm in a lap configuration. Welding was performed using a laser beam power 7 kW of infrared wavelength with core–ring beam shaping and scanning optics. Several seam geometries (spiral-, circular-, C-, infinity-shaped, and lines) were produced with a constant seam length of 20 mm. All welds were generated using a welding speed of 15 m/min.

The results reveal how different seam geometries influence the effective connection width and thereby affect both electrical resistance and mechanical strength. The study provides a better understanding of the relationship between weld geometry and joint performance and supports the optimization of laser welded copper connections for electrically demanding applications.