The influence of different phase matching between lead and trail machines on the arc of tandem twin wire pulsed gas shielded welding is studied. There are four stages in the phase matching of lead-trail machine twin wire coordinated welding. Mode 1 is that the lead and trail machines output pulses at the same time

at this time

the lead-trail machine pulse is in phase matching;mode 2 is that the lead machine arrives at the pulse peak stage

and the trail machine starts to output pulse;mode 3 is that the lead machine is at the pulse descending stage

and the trail machine outputs pulse;mode 4 is that the lead machine is at the basic value stage

and trial machine starts to output pulse. The second generation twin wire welding system newly developed by Panasonic is used to carry out welding test. The results show that in mode 1

because the two arc of lead-trail machines are in peak stage at the same time and completely coincide

the interference is large

resulting in large spatter. In mode 2

the peak phase of the lead-trail machines overlaps

and there is arc interference

which is smaller than that in mode 1

and there is also large spatter;In mode 3

the lead machine pulse droplet begins to fall off. If the trail machine starts to output pulse at the early stage of the lead machine pulse falling edge

it will produce arc impact on the metal transfer of the lead machine and generate spatter

which is smaller than that in mode 1 and mode 2. When the falling edge of the lead machine is close to the basic value

the trail machine outputs pulse again

the spatter is small and the arc is stable. In mode 4

the lead machine enters into the basic value stage and is in the arc maintenance period

and the current is small. At this time

the trail machine outputs pulses

and the arc of lead machine may be broken. If the arc of lead machine is normal

the welding effect is good

the spatter is small and the shape is beautiful. When the lead machine is at declining stage and droplets fall off

the trail machine outputs pulse

and the phase matching is the most appropriate and the welding effect is the best. When the set voltage or extension length of welding wire of the lead machine changes

the phase matching time is automatically adjusted.