In-Situ Monitoring of Melt Pool Dynamics in Laser Cladding using Numerical Simulation and Spectral Diagnostics

In-situ monitoring and precise control of melt pool dynamics play a key role in determining the quality and uniformity of cladded Layers in laser additive manufacturing processes.This research presents a hybrid approach combining numerical simulation using the Goldak model and real-time monitoring with laser-induced breakdown spectroscopy (LIBS) in the laser cladding process of Inconel 718 alloy on 304 stainless steel substrate. Accurate modeling of the thermal dynamics of the melt pool and simulation of the clad layer dimensions were performed under various input parameters, including laser power, scanning speed, and powder feed rate, across 64 cladding samples. The clad cross-sectional dimensions and dilution degrees were validated against experimental measurements.To minimize model errors, spectral diagnostics was employed for real-time monitoring of melt pool variations, providing indirect but precise information on the local melt pool temperature and elemental composition. The plasma temperature, derived from chromium atomic lines in the spectral range of 400–500 nm, accurately tracked the cladding temperature changes based on input parameters. Meanwhile, the intensity ratio of nickel to iron lines (361.93 to 382.94 nm) effectively quantified the degree of dilution in the clad layer. This approach enables dynamic calibration of process input parameters by integrating the acquired data, ensuring uniform clad layer quality through real-time control of melt pool temperature variations and dilution degree.