Molten pool dynamics

This study introduces an in-situ monitoring method for laser processing based on specular reflection of the molten pool surface, enabling high-resolution observation and feature extraction of molten pool dynamics. By analyzing the molten pool surface, keyhole opening, and specular micro-region under varying laser powers, it identifies the specular micro-region as the most sensitive and representative parameter due to its strong periodic behavior linked to laser–keyhole interactions. The findings provide a novel approach for understanding energy transfer mechanisms and offer a reliable foundation for real-time monitoring and intelligent control in laser manufacturing processes.

This study demonstrates that combining nitrogen shielding gas with a reduced laser spot size can effectively suppress humping and root sagging defects in high-speed laser welding of stainless steel foil. By stabilizing molten pool dynamics, reducing oxygen content, and optimizing surface tension gradients, the approach significantly improves weld quality and mechanical performance, achieving defect-free welding at higher speeds while providing a predictive model for process optimization.

This study explores the application of circular laser beam oscillation in narrow-gap welding of 5A06 aluminum alloy thick plates, demonstrating that oscillation significantly improves molten pool stability, modifies flow behavior, and enhances sidewall fusion. By combining experimental validation with numerical modeling, the research confirms that circular oscillation effectively suppresses lack-of-fusion defects, reduces plasma plume energy loss, and improves weld quality, providing a reliable solution for high-performance thick plate laser welding applications.

This study systematically reviews the principles, modeling methods, and solidification mechanisms of laser wobble welding (LWW). Through analysis of heat transfer, molten pool dynamics, and multi-physics simulations, it reveals how beam oscillation stabilizes welding and refines microstructure. The paper highlights current research gaps—particularly in solidification modeling—and proposes directions for developing high-fidelity, data-driven models to enhance weld quality and industrial application.