Effect Of Operating Variables; Operating Guide - Lincoln Electric INNERSHIELD Series Welding Instruction Manual

To Minimize Arc Blow (In order of importance)
Arc blow occurs when thr arc stream does not folow the shortest
path between the electrode and the workpiece.
1. Move work connection locations
2. Decrease drag angle
3. Increase CTWD
4. Decrease WFS and voltage
5. Decrease travel speed
To Eliminate Stubbing (In order of importance)
Stubbing occurs when the wire drives through the molten
puddle and hits the bottom plate tending to push the gun up.
1. Increase voltage
2. Decrease WFS
3. Decrease CTWD
4. Decrease drag angle
Equipment Troubleshooting Instructions are included in the
operating manuals for the wire feeder and power source. Be sure
to confirm the equipment is operating properly.

EFFECT OF OPERATING VARIABLES

The four major operating variables, arc voltage, wire feed speed
(WFS), travel speed and CTWD, are interdependent. If one is
changed, usually the other three must also be adjusted.
Arc Voltage
If WFS, travel speed and CTWD are held constant, changing the
arc voltage will have the following effects:
1. Higher arc voltage results in a wider and flatter bead.
2. Excessive arc voltage causes porosity.
3. Low voltage causes a convex ropey bead.
4. Extremely low voltage will cause the wire to stub on the plate.
That is, the wire will dive through the molten metal and strike
the joint bottom, tending to push the gun up.
Wire Feed Speed (WFS) - (or welding current)
If arc voltage, travel speed and CTWD are held constant, WFS
variations have the following major effects:
1. Increasing the WFS increases melt-off and deposition rates.
2. Excessive WFS produces convex beads. This wastes weld
metal and results in poor appearance.

OPERATING GUIDE

– 26 –