German Team Experiments Prove: Green Light Laser Automotive Electronics Welding Can Significantly Save Raw Materials

A collaborative German research team recently announced an advancement in which they have worked together to provide the most detailed insight into the laser welding process to date. The joint team clearly demonstrated for the first time that raw material can be saved when welding high-performance electronics through the use of green wavelength lasers.
The team includes the results of an investigation completed in collaboration between TRUMPF, the Fraunhofer ILT and DESY, a large particle physics research institute of the German Helmholtz Association. Every electric vehicle is equipped with high-performance electronics as a key technology that ensures optimal performance of the battery and motor.
Several of the companies and institutions mentioned above are working together on laser welding processes for the manufacture of electric vehicles, contributing their highly specialized knowledge of X-rays, laser sources and welding processes, respectively. They have found that when using green wavelength lasers, the scrap rate generated is much lower than other laser welding processes, thus helping automakers achieve significant savings in raw materials and benefiting more sustainable manufacturing.
During the study, they took high-speed images at several thousand to 10,000 frames per second, hoping to use particle gas pedal X-rays to study to understand exactly what causes the difference in copper welding results.
Marc Hummel, a scientist at the Fraunhofer Institute of Technology (Fraunhofer ILT), noted that a stable welding process is important because electric vehicle manufacturers often need to complete billions of high-quality connections. In the future, TRUMPF and Fraunhofer ILT plan to expand their research into other areas, such as 3D printing, laser cutting and ultrashort pulse laser punching, and to include other industry partners in the aforementioned collaborative teams.
Lower scrap rates with green wavelength lasers
The manufacturing process of electric vehicles poses a very big challenge for laser technology. Copper is the most important material for manufacturing the core components of electric vehicles, a non-ferrous metal that absorbs only about 5% of laser radiation in the near infrared (NIR) range and has very good thermal conductivity. Unfortunately, both of these properties can cause considerable problems when soldering. Therefore, these processes usually require a subsequent close nuclear check.
In addition to NIR lasers, green wavelength lasers are also available in the Trumpf product portfolio. Lasers with green wavelengths are the solution to this problem," notes Mauritz Mοller, Trumpf's automotive industry manager. In fact, copper can be welded better using these lasers."
Copper absorbs green wavelengths much better than it does infrared. Because the material reaches its melting temperature faster, the welding process also starts faster and requires less laser power. Finally, a more stable welding process also results in lower scrap rates, which contributes to more sustainable manufacturing.
Particle gas pedal experiments
To study the welding process in detail, experts from the Fraunhofer Institute for Industrial Technology in Germany have entered into a collaboration with the Institute for Laser Technology at RWTH Aachen University in Germany, where they are using DESY's PETRA III X-ray light source in an experimental setup at the Helmholtz Centre in Germany.
Marc Hummel explains: "Conventional methods can actually only see the electromagnetic emission of the plasma. With DESY's radiation, we can not only see the inside of the melting, but we can even see the dynamics of the melting in real time."
To this end, the team from Fraunhofer ILT and Trumpf studied the laser welding process at DESY using two different laser systems (near-infrared laser and green wavelength laser.) Mauritz Mοller said, "For us, this is a great opportunity to study the welding process of industrial parts. For example, how spatter and porosity are formed and how the heat from the welding process affects sensitive parts such as electronic components."