Active metal transfer control by monitoring excited droplet oscillation

Controlled metal transfer implies controllable heat and mass inputs and improved weld quality. Success of previous methods has been hindered by uncertainty in droplet detachment. In the proposed approach, an oscillation of the droplet is excited by switching the current from a peak level to a base level to initiate an active detachment period. The droplet oscillation is then monitored. When the droplet moves downward, the current is switched back to the peak level, which creates an ejection action and concludes the active detachment period. The droplet is detached by downward momentum and the increased current-induced electromagnetic force. Growth period of the succeeding cycle begins. The utilization of downward momentum eliminates the need for a very high current to detach the droplet, which is conventionally used in pulsed gas metal arc welding (GMAW-P). This elimination guarantees that no unexpected detachment occurs during the growth period. Also, reliable high-frame rate vision monitoring of the oscillating droplet guarantees that downward momentum will correspond with the ejection action. Hence, the metal transfer process can be precisely controlled. Experimentation has been conducted to demonstrate the effectiveness of the proposed approach in achieving the desired metal transfer process.