Active metal transfer control by utilizing enhanced droplet oscillation part 1: Experimental study

Active metal transfer control utilizes an excited droplet oscillation to produce robust drop spray/small globular transfer with peak current lower than the transition current in gas metal arc welding. The excitation is intentionally generated by reducing the current from a peak level, referred to as the exciting peak, to the base level. Another peak level, referred to as the detaching peak, is then applied after a time interval called the detaching phase delay to synchronize the detaching action with the beneficial droplet momentum as a phase match such that the droplet detachment is enhanced by the beneficial momentum. In a recent study, the droplet oscillation was significantly enhanced through current waveform modification. The active metal transfer utilizing the enhanced droplet oscillation, referred to as the enhanced active metal transfer control, was further systematically studied in this investigation. The effect of the detaching phase delay on the droplet detachment was experimentally analyzed first, and the general property of the optimal detaching phase delay for the most enhanced droplet detachment was thus revealed. Consequently, the effect of the current waveform parameters on the optimal detaching phase delay was examined. Then a series of enhanced active metal transfer control experiments were conducted by using corresponding optimal detaching phase delay. It was found that the minimum detaching peak current in the enhanced active metal transfer control was not only remarkably lower than the transition current, but also significantly lower.