With an expansion in automation of welding process, emphasis has shifted from other welding process to GMA welding. However, there is a problem with this process in that spatter occurs more frequently. In GMA welding, there are several types in the way or the manner of metal transfer from the electrode wire to the weld pool.
This study was concerned with a spatter in short-circuiting transfer. In welding with short-circuiting, the electromagnetic forces formed by the welding current facilitate the rupture of a bridge and ensure the normal course of a welding process. However, it may cause spatter from the droplet because of upward magnetic force when droplet contact with weld pool. The passage of current through the bridge results in the accumulation of thermal energy, which causes the bridge to explode in the final stage of short-circuiting, thus forming metal spatter. Based on the above phenomena in conjunction with other experimental results published, the current waveform was controlled to reduce the spatter. It was revealed that the quantity of spatter was reduced by the proposed current waveform compared with that of the conventional welding power source.
