Similar copper connections in different material thicknesses are common in electrical, mechanical and plant engineering, the automotive and aviation industries or electronics production. Laser beam welding with laser beam sources emitting infrared wavelength is a suitable method for realizing this connection. Material thickness starts in the area of 0.3 mm and goes up to the 2 mm range. The thicker material is preferably applied on the top, but some applications require a different approach. Most important is the resulting electrical resistance as well as the mechanical strength regarding component lifetime. Both are related to the connection width.

Investigations for pure copper with sheet thicknesses of 0.5 mm and 1.0 mm were conducted using a laser beam power of up to 8 kW with core-ring technology and scanning optics. These investigations focused on different seam geometries (spiral, circle, and lines) and various lengths (20 mm and 30 mm) of these geometries. Suitable welding parameters (energy per unit length, welding speed, laser beam power, power ratio in the core, focal position) are determined beforehand in order to realize comparability. The influence on the connection width, the electrical resistance, and the seam strength is investigated. Furthermore, research is carried out into the arrangement of the sheets with regard to the choice of material thickness of the upper joining partner.