Stable laser welding of copper materials

In the field of electronics and electrical engineering millions of copper and copper alloy connections are welded every year. Laser welding is often used, since it is very flexible and can be easily automated. However, the infrared beam used for welding is not evenly absorbed by copper materials. Hence, the quality of the weld may vary greatly, and in extreme cases a connection might not be made, or workpieces may be perforated. The reasons for this may be impurity, oxide layers and varying roughness of the copper surface.

Preconditioning with a green laser

Now, the engineers of the Machines and Controls Group at the Laser Zentrum Hannover e.V. (LZH) want to increase the stability of laser micro-welding of copper and copper alloys. For this, they plan to precondition copper materials using a short wavelength green laser beam (532 nanometers). The preconditioning of the surface has already been tested successfully for pulsed laser welding. The scientists now want to establish this method for continuous wave welding.

Increased process stability, shorter processing times

The conditioning of copper can increase the amount of laser radiation being coupled into the surface significantly. This, on the one hand, improves the process stability, and on the other hand shortens the process time. A further advantage of this approach – especially for small and medium sized enterprises – is: existing equipment with infrared beam sources can be easily refitted. Preconditioning would make laser welding of copper materials a very economical process with a high throughput.

The project “Surface conditioning of copper materials to stabilize continuous wave laser micro-welding” is supported by the German Federation of Industrial Research Associations "Otto von Guericke" e.V. (AiF).