Lincoln Electric IM892-C manual Upslope, Burnback, Postflow

B-44 OPERATION B-44

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. (See Figure B.20)

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 estab- lished within 1.5 seconds, the power source output and wire feed speed skips to the weld settings.

UPSLOPE:

Once the wire touches the work and an arc is estab- lished, 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 set- tings 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 contin- ues for the burnback time.

POSTFLOW:

Next, the machine output is turned OFF and shielding gas continues until the post flow timer expires.

	Trigger Pulled
Idle	Preflow

Shielding On
Gas	Off

FIGURE B.20

		2 Step Trigger
		Start = ON
		Crater = OFF
	ArcEstablished	Burnback = ON
Strike Upslope			Weld

Trigger Released

Burnback Postflow Idle

Power	Weld		Start tim e
		1.5 sec max.
Source	Start			Burnback Time
Output
	Off

Weld

WFS

Run-in

Off

POWER FEED™ 25M