Yangtze River Delta G60 laser alliance guide
据悉，德国通快的研究人员报道了利用高功率激光器的动态光束整形提高发卡定子的生产率研究，为电动汽车行业创造机遇。 相关研究以“Unlocking opportunities for the EV industry with beam shaping of high-power lasers”为题发表在《PhotonicsViews》上。
Driven by the global shift to sustainable transportation, the electric vehicle (EV) industry is experiencing unprecedented growth. Laser welding has become an important technology in the industry, providing a convenient way to reduce production costs and expand manufacturing options for new battery and electric drive technologies. Although lasers are rapidly evolving, with power levels reaching 24kW and beyond, it is still a challenge to effectively apply such high laser power in the welding process.
This article explores the gap between the available laser power in the hairpin welding process and the conversion of it into higher productivity. These limitations, especially in the dynamics of the melt pool, prevent the full potential of high laser power from being realized. To address this challenge, researchers explored innovative beam shaping methods to overcome these limitations and utilize higher laser power during the welding process. Through a detailed demonstration, the researchers showed how new beam shaping techniques can be applied to put higher laser power into practical use in welding, thereby increasing productivity to unprecedented levels. This research not only helps to optimize laser welding of EV components, but also opens the door to a wider application of advanced manufacturing technologies.
Over the past few years, the EV industry has rapidly evolved from a small manufacturing plant to a large-scale manufacturing plant. Advances in production technology, such as scanner-based laser welding, have facilitated this shift, making production much faster than any other technology. The demanding requirements of battery and electric vehicle production have also accelerated the development of higher power and brightness laser sources, which in turn has increased the need to develop new applications to use these advanced tools. Beam shaping is a key method that can use higher power lasers to push the limits of processing to a higher level, opening the door to increased productivity. Below, we'll look at the advancements in hairpin welding and how you can reduce welding time by up to 2.5 times by adjusting spot size and laser beam profile.
Superimposed laser beams
Welding the contacts of various batteries or electronic drives, which are mainly made of aluminum, copper, and steel, requires a low-spatter process with low input heat and no porosity in the weld. In addition, the penetration depth and volume of the molten material should be kept to a minimum. To meet these requirements, the process must be stabilized by controlling the shape and dynamics of the keyhole and the surrounding melt pool.
To address these characteristics, the researchers used a TRUMPF BrightLine Weld welding method to control the welding process by stabilizing the keyhole. This is achieved by superimposing two laser beams, one core beam and one ring fiber beam. This will have a stabilizing effect on the keyhole and the surrounding melt pool. This innovative technology is widely used in a wide range of applications involving copper, aluminum, and steel components, such as the electric vehicle industry.
Figure 1 shows the beam profile of an overlaid laser beam from a TruDisk BrightLine Weld laser source in the focal plane. The sketch shows that two beams are superimposed on top of each other and are introduced into the keyhole. As a result, the keyhole opening is conical in shape compared to the absence of a ring beam, which is the main effect of stabilization during machining. This phenomenon not only creates a stable keyhole, but also results in a significant increase in molten material near the surface. Both of these effects are essential to reduce spatter and pore formation.
Figure 1 Effect of BrightLine Weld on the welding process. The laser beam is coupled to an inner fiber core and a coaxial ring fiber.
Table 1 Experimental configuration
Welding results
The laser-based hairpin welding process is a major challenge as it requires precise and fast connections while minimizing porosity, heat input, and spatter. To prevent instability and achieve a precise connection in the hairpin stator design, a deep understanding of the process is essential. At the same time, there is a need to maintain high process efficiency, minimize material loss, and optimize cycle times while maintaining structural integrity. Multi-mode lasers with 2-in-1 fiber guiding function are mainly used for welding copper hairpins, with high laser power and strict quality requirements. Compared to other high-power beam shaping technologies, TRUMPF's BrightLine welding technology, which can be used for disc lasers and fiber lasers, utilizes the full laser power. Optics for fiber coupling are designed to support interchangeable fibers and integrate multiple beam outputs while maintaining beam quality integrity.
Figure 2 BrightLine Weld optical wedge used to adjust the power distribution between the core and the ring fiber.
To address the challenges of short process times and minimizing spatter and porosity, BrightLine Weld technology is used to ensure a strong, conductive connection that significantly reduces porosity and spatter compared to processes using core fibers alone (see Figure 3). Dynamically adjusting the laser power split ratio between the core and ring fibers during the welding process provides a synergistic approach that combines fast processing times with reduced porosity. Throughout the welding process, the laser power alternates between the core and ring fibers to optimize the results. Although the spatter is reduced, a small amount of spatter can still be observed under this process strategy.
Figure 3 Comparison of welding performance of the TruDisk 8000 multimode laser using a single-core, static, and dynamic BrightLine Weld process. The corresponding spatter and porosity images show an increase in the speed and quality of the dynamic BrightLine mode process.
To meet the challenges of short processing times, spatter, and porosity minimization, the application of BrightLine Weld technology ensures a robust conductive connection, significantly reducing porosity and spatter compared to processing with core fibers alone (see Figure 3). Dynamic adjustment of the laser power distribution ratio between the core and ring fibers during the welding process provides a synergistic approach that combines fast processing times with reduced porosity generation. Throughout the welding process, the laser power alternates between the core and the ring fiber to optimize the welding results. With this process strategy, a small amount of spatter can be observed, although the spatter is reduced.
Article Links:
https://doi.org/10.1002/phvs.202400017
Welcome everyone to participate in the activities held by the Yangtze River Delta G60 Laser Alliance:
Application of laser intelligent manufacturing in new energy vehicles:
July 29-31, 2024, Hefei Fengda International Hotel, Anhui
Welcome to the conference and exhibition!