Design of a physical simulation system for controlled generation of molten metal droplets

Wire Arc Additive Manufacturing (WAAM) is widely recognized for its high deposition efficiency and material utilization; however, its forming accuracy and process controllability remain limited due to the strong coupling of heat and mass transfer. To decouple molten droplet behavior from the arc environment, a pulsed gas-pressure-driven physical simulation platform was developed for controlled droplet generation and mechanism investigation. Experiments were conducted over a temperature range of 700–1200 ℃, with a nozzle diameter of 0.6 mm, pulsed gas pressure of 26–42 kPa, and gas opening time of 30–70 ms. The results demonstrate that, under single-parameter regulation, critical thresholds at approximately 900 °C, 36 kPa, and 50 ms induce a transition from the multiple pulses per droplet mode to the one pulse per droplet mode, resulting in discontinuous variations in droplet size. To overcome this limitation, a multimodal coordinated control strategy combining pulsed gas pressure and gas opening time was proposed and experimentally validated. By enabling continuous tuning of effective energy input, gap-free and continuous regulation of droplet size was achieved, eliminating size discontinuities and expanding the stable control range. The proposed system provides an arc-decoupled and highly controllable platform for investigating molten droplet dynamics. The demonstrated coordinated control strategy offers a practical pathway for improving droplet transfer stability and dimensional accuracy in WAAM, and supports the development of intelligent droplet control in metal additive manufacturing.