Excitation of droplet oscillation in CO₂ shielded welding based on arc force regulating

Numerical simulation of droplet surface in CO₂ shielded welding was performed based on Surface Evolver software. The droplet profile of different size at different welding current were predicted. The results indicates that the droplet can change from repelled status to pendant status when the current switches from peak to base. During this process,the droplet even can be excited to oscillation. Experiments with pulsed current waveform were conducted to verify these predictions. Results show that the droplet is repelled during the peak duration and changed to vertical pendant profile when the current is changed to base. When the droplet size is properly controlled to be relatively small,the droplet will not be repelled during the peak but only wire-axially compressed. In this case,when the current changes to base,the droplet would be excited to a damping oscillation. This kind of oscillation could be synchronously utilized to enhance the droplet detachment.