Indirect numerical assessment of spatter accumulation in laser welding based on a reinitialized level set framework

Understanding the correspondence between regional melt pool dynamics and spatter generation is important for interpreting laser welding behavior. This study proposes an approach that combines a reinitialized level set model with experimental observations to examine regional numerical proxies of spatter accumulation. Three complementary proxies, metal phase volume, metal phase kinetic energy, and interfacial activity, are extracted directly through spatial integration without additional temporal accumulation. Five region of interest (ROI) configurations are investigated to distinguish the effects of size, position, and shape, while three laser powers enable comparison across different energy inputs. The simulations reproduce the experimentally observed increase in weld width with power. ROI selection affects proxy magnitudes, while the principal temporal trends are retained, including increases in kinetic energy and interfacial activity. Experimental spatter occurs intermittently, but cumulative counts consistently increase with power. Comparisons show that the overall increases in the kinetic energy and interfacial proxies are consistent with the experimentally observed growth in cumulative spatter counts. Cumulative indicators provide a complementary description by retaining successive changes in the regional quantities. These suggest an initial association between regional melt pool dynamics and experimental spatter accumulation, supporting further development and assessment of indirect spatter descriptors. As a proof of concept, this study provides a framework for examining overall spatter accumulation through regional melt pool quantities without explicitly resolving individual droplet detachment.