Multimodal monitoring and predictive modeling for stability and overlap control in arc-based directed energy deposition

Abstract This study proposes a comprehensive methodology for validating process parameters in pulsed gas metal arc welding (GMAW-P) applied to arc-based directed energy deposition, aiming at the production of weld beads with controlled geometry and process stability. Shadowgraphy was employed for metal transfer visualization, combined with stability analysis algorithms and metal transfer criteria. Fast Fourier transform (FFT) was applied to current and voltage signals to identify the most efficient pulse characteristics, droplet detachment behavior, and transfer frequency. An analytical formulation correlating wire feed rate, travel speed, and bead cross-sectional area was used to guide the selection of deposition parameters. In addition, a theoretical analysis of bead overlap was developed and its predictions were directly compared with experimental results, demonstrating good agreement and validating the proposed model. These strategies defined a stable working window with voltage between 22 and 28 V and current between 190 and 220 A. The optimal condition was obtained at a frequency of 240 Hz. The proposed methodology enables parameter adaptation for different materials, ensuring energy efficiency, cost reduction, and geometric consistency. Moreover, GMAW-P allows the production of high-quality deposits at lower current levels compared to conventional GMAW.