Improving accuracy and precisely controlling molten pool of stepped filling wire–assisted DP-GTA-AM

Conventional wire arc additive manufacturing (WAAM) possesses inherent attributes, including the robust coupling interaction between the arc-droplet and the weld pool, non-linear time-varying, and heat accumulation. These characteristics often lead to suboptimal deposition processes and morphologies. This paper introduced a novel double-pulsed gas tungsten arc welding additive manufacturing (DP-GTAW-AM) process, which utilized a stepped filling wire to achieve independent control of heat input and mass transfer during the WAAM process. The fundamental principle of the proposed process was illustrated, and the construction of the experimental system was detailed. A series of experiments was conducted to verify the decoupling of heat-mass transfer. Moreover, the droplet transfer behavior, molten pool variation, and morphological changes as deposition layers increase were analyzed utilizing visual images and mathematical modeling. The results indicate that a stable heat-mass transfer process is achieved, resulting in deposited layers with the desired accuracy. This demonstrates the feasibility of improving deposition accuracy in WAAM by controlling pulse parameters. This approach offers a promising method for precise control of deposition accuracy in industrial WAAM applications.