Surface feature retardation in laser-based metal processing via dynamic bimodal beam modulation

Laser-based metal manufacturing techniques, such as laser welding and additive manufacturing, offer high precision and versatility, but the complex melting and resolidification processes often lead to uneven surface morphologies. This study investigates the effects of dynamically modulated bimodal beam shaping on metal surface topography. Two independently controlled Gaussian beams were super-positioned, with one beam oscillating sinusoidally to modulate the bimodal intensity profile both spatially and temporally during laser processing. At low oscillation frequencies, periodic surface features emerged, whereas high modulation frequencies produced smooth melt tracks. Simulations indicate that higher frequencies promote a more uniform spatial energy distribution and reduce melt durations. These results highlight the potential of tuning dynamic bimodal beam shaping parameters to actively control and suppress unwanted surface features, offering a framework for improving surface quality in laser-based manufacturing processes.