Meso spray transfer in GMAW of aluminum and its control

Meso spray transfer mode in GMAW of aluminum exists in a very narrow arc voltage, which makes it very difficult to be controlled. Traditionally, meso spray transfer mode is applied for GMAW of aluminum with constant current. The method is not liable to be used for medium plate more than 6 mm thick. Through analyzing the characteristic of meso spray transfer mode, an adaptive control method is developed to adjust welding current according to arc voltage. The frequency and value of the welding current will change in pulsed mode with fluctuation of the arc voltage, thus match with the wire feed rate. With the adaptive control method, the droplet transfer mode is kept in the meso transfer zone. A control circuit is designed based on the method and the welding technology experiment result shows that the control system can provide a stable process of welding with meso transfer mode. The new developed GMAW welding technology is suitable for medium plate welding.