Design and experimental evaluation of data-driven process control strategies for wire DED-LB additive manufacturing

Wire laser-based Directed Energy Deposition (DED-LB) enables high material utilization and the fabrication of dense metallic components; however, its industrial adoption is hindered by trial-and-error process tuning required when introducing new geometries or materials to ensure stable deposition and compliance with quality requirements. This work presents monitoring-assisted strategies for the design and implementation of feedback control in wire DED-LB using an off-axis vision-based system. Multiple decision-making approaches are evaluated to improve process stability and mitigate heat accumulation during multi-layer deposition. The results demonstrate that the mean melt pool area per layer correlates strongly with surface quality and cross-sectional stability. A proportional (P) controller, combined with a two-variable control strategy based on laser power and dwell-time adjustment, enables stable part growth, improves geometric consistency, and suppresses surface defects over a wide operating range by constraining the melt pool area within a user-defined operating window. Key control parameters, such as proportional gain, laser power bounds, and the target melt pool area window, are identified for AISI 316 L, highlighting their material-dependent nature.