When the trigger is pulled, the pre-gas starts. When the wire touches the workpiece, a pulse initiates the arc and the welding cycle starts. When the
trigger is released, the wire feeding stops and a current pulse cleanly severs the wire, as the post-gas is released. As long as the post-gas has not
finished, pressing the trigger will allow a quick restart of the weld (manual chain stitch) without going through the HotStart phase. A HotStart and/or a
crater-fill can be added to the cycle.
Standard 4T process:
T hotstart
Dstart
4T
Soft-start
In a standard 4T process, the timing of pre-gas and post-gas is managed automatically. HotStart and crater-fill are both controlled by the trigger.