Vision: Laser Welding In Space

Scientists at the LZH are investigating the influence of gravity on laser beam welding processes. Experiments in the Einstein elevator should provide important insights.

In order to equip space stations, fully assembled assemblies currently have to be transported into space. This takes up cargo space and leads to high fuel costs. A solution to this problem could be laser beam welding: With the help of laser beam welding , attachments or spare parts could be joined together directly on site . And instead of replacing entire assemblies, existing equipment can be flexibly expanded, modified or repaired.

Experiments in the Einstein Elevator should provide insights
In space, many of the requirements for laser beam welding are different than on Earth. Among other things, vacuum conditions, radiation, electric and magnetic fields ensure that materials and processes behave differently. The researchers want to investigate exactly how gravity affects molten metal pools in the Einstein Elevator at Leibniz Universität Hannover (LUH).

Specifically, they want to investigate, among other things, the flow behavior for laser beam welding of similar and dissimilar connections made of aluminum alloys and steel materials. For the dissimilar weld seams, the scientists also want to analyze the mixing behavior of the materials in the melt. Furthermore, the influence of the convection, which is greatly reduced under microgravity, on the melt pool and the resulting joints are to be investigated.

The Einstein Elevator from HITec - Hannover Institute of Technology is the further development of a classic drop tower, with which experiments can be carried out under reduced gravity and microgravity (corresponds almost to weightlessness). The achievable microgravity is below 10 -6 g, the maximum test duration is 4 seconds. The microgravity value that can be achieved in the Einstein elevator without a vacuum is around 10 -4 g. This condition corresponds, for example, to the conditions on the International Space Station ISS.

About the µg welding
project The project "The behavior of metallic melts during laser beam welding under microgravity" (µg welding) is being carried out by the Deutsche Forschungsgemeinschaft e. V. (DFG) under the code KA 3952/13-1.