Case Study: BAM German Federal Institute for Materials Research and Testing achieves more uniform, low-defect laser beam welds with COMSOL Multiphysics

Magnets Improve Quality of High-Power Laser Beam Welding

BAM German Federal Institute for Materials Research and Testing faced unstable, hard-to-control high-power laser beam welding of thick aluminum, where low-viscosity melt and strong temperature gradients (Marangoni effect) caused wide, spattered, "wineglass"-shaped welds with underfills and the need for post-weld repair. To address this, BAM worked with Comsol and used COMSOL Multiphysics to investigate whether stationary magnetic fields could stabilize melt flow and improve weld geometry.

Using Comsol’s COMSOL Multiphysics (CFD and AC/DC Modules), BAM simulated 3D heat transfer, fluid flow, and electromagnetics to calculate Lorentz forces and their feedback on the weld pool, iterating to a self-consistent steady-state. Simulations—validated by macrosection comparisons of real welds (e.g., 16 kW at 0.5 m/min)—showed that perpendicular magnetic fields (0.5–2 T) shift the profile from a wineglass to a more desirable V shape, reducing spattering and material loss and improving uniformity, thereby lowering the need for post-weld repair. Comsol’s modeling enabled BAM to identify optimal field strengths and plan scale-up experiments.

BAM German Federal Institute for Materials Research and Testing

Marcel Bachmann

Researcher