Civan Lasers and TU Wien Collaborate for Insights on Laser Welding

Laser experts at Technical University Wien (TU Wien) in Vienna, Austria, have collaborated with Civan Lasers (Jerusalem) to simulate its disruptive dynamic beam laser technology. As a multiphysics simulation software capable of modeling the megahertz-level frequencies of Civan’s dynamic beam lasers (DBLs), the work improves understanding of how these beam-shaping lasers influence control of keyhole and melt-pool dynamics, the companies report.

“The beam-shaping capability of Civan’s laser opens up new possibilities for increasing welding quality and speed in many of today’s challenging applications,” explains professor Andreas Otto at the Institute of Production Engineering and Photonic Technologies, TU Wien. “It's a really significant development that will shape the future of laser materials-processing technology and even open up the development of entirely new applications.”

Providing insight into the effect of each beam shape and frequency on keyhole and melt-pool dynamics, this simulation tool will play a role in process development, helping to optimize beam shape and frequency for various laser materials-processing applications. Current simulations have focused on butt welding of stainless-steel pipe with a gap. Future collaboration will target other welding, drilling and surface treatment applications involving various materials. 

The welding of a stainless-steel pipe in a butt-joint configuration was particularly challenging. The finite precision in the cut pipe fronts plus limitations of the clamping system resulted in a small gap (of the order of tens of microns, up to a few hundred microns). This welding process, which relied on standard static laser sources, did not use filler material, and the result was a gap at the contact line and low-quality weld seams.

To come up with a solution, Civan experimented with its DBL and then collaborated with TU Wien to simulate the process. The result was a better understanding of why certain shapes work better than others. The simulation also helped in the design of alternative beam shapes that might work for this problem and led to the development of general guidelines on how to design suitable beam shapes for such situations.

Civan’s coherent beam combination modulates beam shape as desired at megahertz frequencies, without any moving parts.

Civan’s lasers use optical phased array coherent beam combining, which merges many single-mode laser beams into one larger beam. Each laser emits its own light, which overlaps with other beams in the far field, to create a diffraction pattern that unlocks the flexibility needed to easily manipulate the beam shape in real time to create a DBL. By using phase modulators to control individual beams, the resulting interference pattern can be changed to maximize the beam spot position and produce various shape patterns inscribed by the beam's motion.

“We have a very powerful tool offering complex control of many parameters, such as beam shape, shape frequency, shape sequencing, and focus steering,” explains Dr. Eyal Shekel, CEO of Civan. “Until now, we’ve used basic theory, intuition and experience to guide us in process optimization. Dr. Otto’s novel simulation tool for beam-based manufacturing processes is a real eye-opener and provides key insights into the dynamics of the keyhole, melt pool, and resolidification, so every problem should start with a good simulation such as this.”

Sources: Press materials received from the company and additional information gleaned from the company’s website.