Behavior and stability of droplet transfer under laser-MIG hybrid welding with synchronized pulse modulations

Abstract

In order to explore the synergetic effect on the process combination of pulsed laser and pulsed MIG hybrid welding, two kinds of coupling modes were performed by modulating the laser power to synchronize the arc current. The results showed that under the in-phase coupling mode, the addition of a high power laser during the peak period of the arc current increased the formation and separation time of the droplet and resulted in the deviation of droplet from the wire axis. This caused the droplet to be easily hit by the laser beam and reduced the stability of the droplet transfer. Moreover, the enlarged laser-induced plasma led to a significant loss of the laser energy. In contrast, under the anti-phase coupling mode, the application of a low power laser during the period of the highest arc current suppressed the arc length becoming longer and resulted in faster droplet separation, fewer weld spatters and smoother droplet transfer. At the same time, compared with the weld of in-phase laser-MIG hybrid welding, the weld of anti-phase laser-MIG hybrid welding had the advantages of deeper penetration, fewer weld spatters, less porosity and better tensile properties.