This blog was written in conjunction with Florian Hugger from BBW Lasertechnik , the leading innovative laser material processing experts Automotive manufacturers use laser welding on a daily basis to create integral vehicle parts that must pass rigorous safety standards. Laser welding has proven to be very powerful in steelwork. However, as the automotive industry shifts to e-mobility, automotive parts use much more copper and aluminum for the required electronic components. The increased thermal conductivity and low absorption of those materials leads to distortions and defects in the final weld. Here are 5 main challenges in the automotive parts laser welding: Cracking in Metals Porosity High-Speed Welding Dissimilar Metals Asymmetric Parts Laser Welding with Dynamic Beam Lasers Cracking in Metals Especially when welding aluminium alloys and high-carbon steels, cracking is a common defect that renders parts unusable. Hot and cold cracks are formed when the laser makes the parts pull apart by thermal shrinkage, so what’s needed is a laser on either side of the weld in order to push the parts back together to counteract the shrinkage that would cause cracking. The current solution is to induce a second heat field, by using either an additional laser or via induction heating. (source Göbel, G: Erweiterung der Prozessgrenzen beim Laserstrahlschweißen heißrissgefährdeter Werkstoffe) A second laser is preferable because minimal heat is being used very locally, but a second laser is very expensive. Induction heating is more economical, but you must heat the entire part which means there is a huge amount of heat going into the material leading to high distortion. (source Göbel, G: Erweiterung der Prozessgrenzen beim Laserstrahlschweißen heißrissgefährdeter Werkstoffe) A lesser used solution are DOEs (diffractive optical elements). DOEs are inflexible and only offer one shape and movement in a single direction. To truly solve the challenge of cracking, we need a flexible laser that can provide a primary heat spot for the weld with two secondary heat spots keeping the metal pushed together. Porosity Porosity is caused by an unstable keyhole and the collapse of the vapor capillary. Different techniques are being tried in order to create a more stable keyhole and reduce porosity, but an ideal solution has yet to be found. (source Hohenberger B.: Laserstrahlschweißen mit Nd:YAG-Doppelfokustechnik) Oscillation with a scanner at a very high speed can work to stabilize the keyhole, but the shapes that can be used are inflexible. The most common shape for oscillation is a spiral, but it is not fast enough to prevent porosity and its inflexibility limits its potential. (source Fetzer et al.: Reduction of pores by means of laser beam oscillation during remote welding of AlMgSi) Another option to stabilize the keyhole is to try to open the keyhole at the top to improve degassing. This means changing the keyhole from an “I” shape to a “V” shape, which is currently done using multicore fibers. Similar to oscillation, this solution is inflexible because it can change the power of the inner and outer fiber cores, but cannot change the size or shape of the keyhole. (source Leimser, M: Strömungsinduzierte Einflüsse auf die Nahteigenschaften beim Laserstrahlschweißen von Aluminiumwerkstoffen) Finally, power modulation has also been tried as a way of stabilizing the keyhole. This solution is limited because it does not allow for varying levels of evaporation on either ends of the keyhole. Right now, we do not know what could be the best solution to prevent porosity because testing is limited by the inflexibility of the lasers. Once we can overcome this barrier and test various beam shapes and rotating heat spots, we will be able to test for an optimal solution. High-Speed Welding A higher speed of welding means a higher likelihood of defects. Usually, the weld is limited to a speed of ½ m/sec while anything above that causes humping and undercuts because the velocity of the melt is too high. 700 mm/s Single-spot (from BBW) The situation is slightly improved with double-fiber lasers because the additional heat source creates a larger melt pool which is slower and more stable. 700 mm/s Multi spot (source BBW) Beam oscillation with a scanner is not possible at such high speeds as in the low frequency the spiral stretches out and cannot serve its purpose. Here again, the inflexibility of today’s technology prevents the testing of new beam shapes and frequencies to find the optimal solution. Dissimilar Metals When welding metals of different types - i.e. aluminum and copper or copper and steel - the objective is a homogenous weld, but often the scanner is too slow to make this happen. When materials are intermixed improperly, the result is brittle faces and cracking, particularly when dealing with aluminum and copper. (source BBW) It is possible to weld dissimilar metals when both are very thin (0.5 mm). In this case, less power is needed and a scanner with smaller mirrors can go fast enough to create a solid weld. But, as soon as we are dealing with metals that are even 1 mm thick, a larger scanner would be needed which cannot move fast enough. Dynamic Beam Shaping would allow the use of 2 laser spots to move at the same time (similar to the movement of a kitchen mixer) and provide the homogenous weld that is needed. Asymmetric Parts When welding two pieces of different thicknesses (such as one machined part that is thick and one thin sheet metal), an asymmetric heat field is needed. Because such a thing does not exist, the solution is to use the amount of heat required for the thick part despite the fact that it is too much for the thin piece. The problem with this is that the more heat that is used, the more distortion there will be. This is a main reason why lasers are used for welding, in order to reduce the heat input. But, when there are asymmetric parts there is currently no solution that generates the right amount of heat for each part. A second challenge related to asymmetric parts is that of gap-bridging - when there is a gap between two parts that needs to be sealed. If, for example, the gap is 50 microns and the laser beam is also 50 microns, it will go straight through the middle and will not seal the edges. The way to solve this situation is either to use a larger laser spot or beam oscillation. (source Hohenberger B.: Laserstrahlschweißen mit Nd:YAG-Doppelfokustechnik) The problem arises when the parts differ and the gap sizes may be smaller or larger - current laser heads are not flexible to adjust for varying gap sizes. Laser Welding with Dynamic Beam Lasers Right now, laser welding is limited by rigid technology. Flexible beam shapes will allow for full testing of many creative solutions that today cannot even be attempted. Dynamic Beam Lasers provide the flexibility needed to solve these challenges: Beam Shaping – Using simple software, quickly and easily design any beam shape. Shape Frequency – Control the frequency of the beam shape from 400Hz –50MHz, which opens a new set of parameters to control the keyhole and melt pool. Shape Sequence – Design a sequence of shapes to maintain the desired shape orientation relative to the feed direction. Focus Steering – In addition to the inherent large depth of focus of the SM beam, shift the focus up to 50MHz without any mechanical components. Dynamic Beam Lasers are the next generation of lasers that will help manufacturers rise above these key welding challenges and produce high quality parts.

Civan Lasers has successfully completed the production of the world’s first 100kW Single Mode (SM) Continues Wave (CW) coherent beam combining (CBC) laser. CBC is a long-time known technology, however so far, Civan is the only company to offer CBC lasers for material processing. Civan is the first to scale up this technology and offer commercial products in a wide range of power levels, proving that it keeps challenging the impossible, and succeeds in doing so. It was only in 2018 that Civan announced its 14kW laser, and now, just three years later, it already expands its groundbreaki ng capabilities to 100kW – 10 times higher than the current competition in the market. The CBC technology is based on parallel amplification of a single seed signal that allows for coherent recombination, ramping the output power to a degree unobtainable by in-series amplifiers . A high-power single mode CBC laser opens the opportunity for innovative and highly useful capabilities. It can be used for welding of thick metals that are found in ships and submarines, and for decommissioning of nuclear plants. One of Civans 100kW CBC unique features that distinguishes it from any other current solution in the market, is its Dynamic Beam Shaping capabilities. This technology provides the ability to control beam shape, frequency, sequence and focus steering, thus allowing to receive a very high quality and defect-free outcome. Civan constantly keeps progressing and developing its technology, bringing new and advanced solutions to the material processing market. The 100kW CBC laser is a revolutionary achievement that sets a very important milestone in that sphere. From now on - only the sky is the limit. About Civan Advanced Technologies: Civan Lasers. was established in 2008 and is the only company to offer industrial lasers based on Coherent Beam Combining technology. Civan's high power lasers are integrated into industrial material processing systems in the fields of cutting, welding, metal additive manufacturing and drilling.

Last month, Civan Lasers CEO, Eyal Shekel, presented a proof of concept to the attendees at the EALA – European Automotive Laser Applications - Conference in an online session together with Valeo’s Jesús Jiménez Palacios, their Senior R&D Expert for Welding/Laser. Valeo is seeking joining technology for the next generation of larger battery coolers for EVs. Currently, Valeo is using a brazing process for welding battery coolers, but are looking for a solution that can provide high quality results at 15m/min for large parts. The existing beam shaping and wobble solution were tested and could not effectively produce a quality weld at this speed. Together with AIMEN, Civan and Valeo set up a testing process in Civan’s applications lab to create a leakproof weld for the Al 3003 battery coolers. Using Dynamic Beam Lasers, each of the variables were isolated and then tested to find the optimal: Power for penetration depth Beam Shape for satisfactory seam width at a speed of 15m/min Shape frequency to eliminate spatter Once the variables were determined, samples were welded and tested for leaks in liquid. The optimal results were achieved with an hourglass beam shape with a frequency of 225kHz. The sample passed the leak test. CONCLUSIONS This test proves that Dynamic Beam Lasers can be a viable solution for the Al 3003 battery coolers. Effective welding of the materials at a rate of 15m/min was achieved with no spatter. The isolated control of beam shapes and frequency allowed for very fast process development. It also showed how spatter can be significantly reduced when adjusting the beam shape and frequency. Testing will find the optimal combination to achieve high quality results even with crack sensitive materials. Want to hear more? Contact us at https://www.civanlasers.com/contact-us

PRESS RELEASE Civan Lasers Partners with SLTL ​Companies will create first 3D Dynamic Beam Laser cutting and welding machine using Coherent Beam Combining SLTL (Sahajanand Laser Technology Limited) and Civan Lasers have partnered to create the first 3D Dynamic Beam Laser cutting and welding machine based on Coherent Beam Combining. This project will create a complete end-to-end system with dynamic beam shaping lasers. SLTL is a leading manufacturer of laser welding machines in India and is well known for its innovation as the first creator of a fiber laser cutting machine. Dr. Arvind Patel, Founder and Chief Managing Director of SLTL commented: “As the first organization to integrate fiber lasers into a laser cutting machine, a fundamental goal for us is to continue adopting the newest and most innovative technology in the market. We’re extremely eager to offer our customers the first 3D laser cutting and welding machine using Dynamic Beam Lasers” Civan Lasers and SLTL will be presenting a completed unit at EuroBlech 2022, which is taking place in November 2022. Eyal Shekel, CEO of Civan Lasers commented: “This strategic partnership will provide laser welders with a complete end-to-end system utilizing dynamic beam lasers and their unique capabilities. We are excited to pioneer this breakthrough in material processing.” This project and strategic collaboration is funded by the Israeli Innovation Authority and the Global Innovation & Technology Alliance. About Civan: Civan Advanced Technologies Ltd. was established in 2008 and is the only company to offer Dynamic Beam Lasers. Civan’s Dynamic Beam Laser allows manufacturers to control beam shape, frequency, sequence and focus steering to eliminate spatter, increase welding power and speed. Through their advanced capabilities, Dynamic Beam Lasers open the door to countless new applications. Visit Civan About SLTL: We, at Sahajanand Laser Technology Limited, want to bring the next door technology to every small and large scale industries. By making the solutions more cost-effective, accurate and future proof, we made it available to a wide range of Industries. We are a market and technology leader in laser cutting and engraving machines dedicated to manufacturing industries. Our innovations play a vital role in virtually every sector from software to high-tech electronics for smart factories. We are one of the few manufacturers in the world providing customized Computer Numeric Controlled (CNC) laser solutions. Visit SLTL Click here for the article by Industrial Laser Solutions

DYNAMIC BEAM SHAPING FOR LASER WELDING Dr. Shekel is the founder and CEO of Civan Advanced Technologies – the first company to develop industrial lasers based on Coherent Beam Combining. Prior to Civan, Dr. Shekel founded Cielo, a leading company in the manufacture of Fiber Optical Gyros and navigation systems and Founder and general manager of Chiaro Networks which developed the largest optical switch in the world. Dr. Shekel received his PhD in physics at NYU. INFLUENCE OF STATIC AND DYNAMIC BEAM SHAPING ON THE LASER WELDING PROCESS Dr. Weber received his PhD in 1988 at the Institute of Applied Physics (IAP) of the University of Bern on the subject of "X-ray emission from laser-generated plasmas". In the following years he headed the research groups "Diode-Pumped Solid-State Lasers" and "Laser Material Processing" at the IAP. Since 2008, he is lecturer at the University of Stuttgart and head of the process development group at the IFSW- Institute for laser Tools. INFLUENCE OF POWER DISTRIBUTION ON WELD SEAM QUALITY AND GEOMETRY IN LASER BEAM WELDING OF ALUMINUM ALLOYS Mr. Eric Punzel, M. Sc.: Has studied Physical Engineering (Laser Technology) in Mittweida, Germany. Currently, he is working as a process development engineer at BBW Lasertechnik GmbH for several years and responsible for feasibility studies in laser welding, cutting and USP (ultra short pulse) machining, as well as the project management for national and international R&D projects.