When the trigger is pulled, the Pre-gas starts. When the wire comes into contact with the metal, a pulse ignites the arc and the welding cycle starts.
When the trigger is released, the feeding stops and a current pulse cuts the wire properly followed by the Post gas. While the Post gas is still going,
pulling the trigger allows to quickly restart the weld (manual chain point) without going through the HotStart phase. A HotStart and/or Crater filler
can be added to the cycle.
Standard 4T process:
T hotstart
Dstart
4T
Soft-start
In standard 4T, the duration of the Pre-gas or HotStart and the Post gas or Crater filler is managed by the trigger.