Analysis of the hybrid pulsed MAG-YAG laser plasma with synchronization of multiple signals

In this paper, a synchronization system is developed for collecting multiple signals of arc plasma which is generated by the hybrid pulsed metal active gas (MAG)-YAG laser welding process. The synchronization system can collect spectra of the plasma, arc voltage, welding current, and high speed video simultaneously. Because the hybrid arc plasma fluctuates with the variation of pulsed welding parameters, acquiring the transient signals is very important for analysis of the coupling effect. With the application of synchronization signals, the transient state of the hybrid plasma can be detected and analyzed. The results show that the interaction between laser beam and welding arc is quite different for different stage of the welding parameter. In the background level of welding current, the laser beam acts directly on the front edge of welding pool, which obviously decreases the effect of diffraction by the solid weld plate. The arc plasma is attracted by the laser and shifts to the laser beam. In the pulse level of welding current, the laser beam acts on the arc plasma rather than directly on the welding pool. The absorption of laser energy by the arc plasma is dominant.