Collaboration between Trumpf, Fraunhofer ILT and DESY (Deutsches Elektronen-Synchrotron, a national research centre in Germany) provides the most detailed of insights into laser welding processes to date thanks to the particle accelerator. Fraunhofer expert Marc Hummel: “We have now been able to clearly prove for the first time that raw materials can be saved in the welding of high-performance electronics by using lasers with green wavelength.”
Trumpf, Fraunhofer ILT, DESY and the Helmholtz Centre Hereon each contributed their highly specialised knowledge of X-rays, laser sources and welding processes. As a result, insights that remain invisible to the eye and even to microscopes have now been achieved for the first time. The result: When a laser with green wavelength is used, far fewer rejects are produced than with other laser welding processes. Car manufacturers save raw materials and thus contribute to more sustainable manufacturing.
Research at the particle accelerator: Trumpf and Fraunhofer ILT have carried out investigations into laser welding at a particle accelerator at the German Electron Synchrotron (DESY) in Hamburg. Image: Trumpf
Particle accelerator provides detailed insights
The project partners used the brilliant X-rays of the particle accelerator at the Hereon experimental setup for their investigation to take high-speed images at several thousand to ten thousand frames per second. “We wanted to use the investigations at the particle accelerator to find out exactly what makes the difference in copper welding. A stable welding process is important because manufacturers of electric vehicles have to weld several billion connections of the highest quality,” said Hummel.
In the future, Trumpf and the Fraunhofer ILT plan to expand research to other areas such as 3D printing, laser cutting and laser drilling with ultrashort pulse lasers, and to bring other industry partners on board.
Investigating laser welding processes: Trumpf and Fraunhofer ILT used a particle accelerator at the German Electron Synchrotron (DESY) in Hamburg to investigate laser welding of copper connections in the high-performance electronics of e-cars. Image: Trumpf
E-mobility: Fewer rejects thanks to lasers with green wavelength
Electromobility poses major challenges for laser technology. Copper is the most important material for the manufacturing of core e-mobility components. This non-ferrous metal absorbs only about five per cent of laser radiation in the near infrared range (NIR) and conducts heat very well. Both of these properties lead to considerable problems when welding.
The processes are therefore under scrutiny. In addition to NIR lasers, Trumpf also has lasers with green wavelength in its product range. “Lasers with green wavelength are the solution to this problem. In fact, copper can be welded better with these lasers,” said Mauritz Möller, Automotive Industry Manager at Trumpf. Copper absorbs the green wavelength much better than the infrared. Because the material thus reaches its melting temperature more quickly, the welding process also starts faster and less laser power is required. “More stable processes when welding mean fewer rejects and thus greater sustainability, which is a major issue in e-mobility,” said Möller.
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