Lincoln Electric POWER FEED 25M NNS Operator's Manual page 29

POWER FEED™ 25M NNS
2-Step Trigger
Example 2: 2-Step Trigger: Improved Arc Start and Arc End
Tailoring the arc start and arc end is a common method for reducing spatter and improving weld quality. This can be accomplished
with the Start and Burnback functions set to a desired values and Crater set to OFF.
For this sequence,
PREFLOW:
Shielding gas begins to flow immediately when the gun trigger is pulled.
RUN-IN:
After preflow time expires, the power source regulates to the start output and wire is advanced towards the work piece at
the Run-In WFS. If an arc is not established within 2.0 seconds, the power source output and wire feed speed skips to
the weld settings.
START:
Once the wire touches the work and an arc is established, both the machine output and the wire feed speed ramp to the
weld settings throughout the start time. The time period of ramping from the start settings to the weld settings is called
UPSLOPE.
WELD:
After upslope, the power source output and the wire feed speed continue at the weld settings.
BURNBACK: As soon as the trigger is released, the wire feed speed is turned OFF and the machine output continues for the burnback
time.
POSTFLOW: Next, the machine output is turned OFF and shielding gas continues until the post flow timer expires.
B 14
OPERATION