Arc characteristics in triple-wire multi-phase pulsed GMAW of aluminum alloy

To address severe arc interference in triple-wire pulsed gas metal arc welding (GMAW) of aluminum (Al) alloy, a triple-wire pulsed GMAW welding platform was established and the arc characteristics under multi-phase conditions were investigated. An arc deflection model for triple-wire GMAW was established, and arc forces during the pulse phase were analyzed. The influences of the torch angle, pulse phase mode, and pulse duty ratio on arc characteristics were investigated. The results showed that varying the torch angle had a significant influence on arc deflection. At a torch angle of 30°, the leading arc reset rapidly when the leading current switched from a base to a peak stage, resulting in stable arc behavior. The arc deflection angles were measured using principal component analysis (PCA). Under the triple-wire alternating phase, the deflection angles of both the leading and right trailing arcs were the smallest. By comparing the projected angles, corrected angles, and model-predicted angles, the model was verified. At the same average current, reducing the pulse duty ratio led to peak arc expansion and increased current density. Under this condition, arc rigidity was optimal, and the deflection angle was minimized. The approximate entropy (ApEn) was used to comprehensively evaluate the stability of the electrical signals. Finally, the preferred welding parameters were identified by combining the analyses of the arc characteristics and the weld formation.