31
Component Identification and Explanation
EXPLANATION OF WELDER FUNCTIONS
Volt and Amp Settings
When welding, the two main functions that require adjustment are Voltage
and Wire feed speed. The function of voltage in MIG welding is to control
the overall width and to a great extent, the height of the weld bead. In
other words, voltage controls the bead profile. It controls wet
-
in at the
toes of the weld, and arc length. Short arc lengths provide wider welds.
The wire feed speed directly controls the amps, and in turn amps control
penetration. When setting the welder up you will notice that the wire
speed is displayed in Inches Per Minute. The relationship between wire
diameter, wire speed and amps is easily figured with the following approxi-
mate industry conversions:
.023”: 3.5
x Amps = Inches per minute (IPM)
.025”: 3.1
x Amps = Inches per minute (IPM)
.030”: 2
x Amps = Inches per minute (IPM)
.035”: 1.6
x Amps = Inches per minute (IPM)
.045”: 1
x Amps = Inches per Minute (IPM)
To convert wire speed (IPM) into approximate Amps, use the following
conversion formula:
.023”:
IPM ÷ 3.5 = Amps
.025”:
IPM ÷ 3.1 = Amps
.030”:
IPM ÷ 2 = Amps
.035”:
IPM ÷ 1.6 = Amps
.045”:
IPM ÷ 1 = Amps
Keep in mind these are approximate conversions and do fall off in accura-
cy as amps are increased into the upper current limits for the given wire
diameter.
Even though you will find general recommendations about setting the
Amps, Volts and even shielding gas through a variety of free downloadable
apps and online calculators, every filler metal manufacturer has its own
specific parameters for Volt and Amp settings for each wire diameter and
class of wire. The ranges of volt and amp parameters generally varies
somewhat from brand to brand, so be sure to read the packaging and/or
manufacturer literature to determine what range of settings are recom-
mended. The wire diameter also limits the practical maximum thickness of
what can be reasonably welded. The issue with following charts, graphs
and calculator recommendations is that most people find them either too
hot or too cold. For some people, it may not be close to the setting they
are used to. However, nothing can substitute for watching and listening to
the arc. If the arc is correct, a steady sound, similar to the sound of
bacon should be heard. The actual frying sound can vary somewhat and
may have somewhat of a higher pitch whine to it. If these sounds are
present, look at the arc to see if it is steady, and producing low amounts
of spatter. If large amounts of spatter are present, the puddle seems fluid
(appears wet) and the wire speed is within the targeted range, decrease
volts a little at a time to reduce the spatter. If this does not correct the
problem, change the torch angle and torch height. Hold the torch more
vertical, with less than a 15 degree deviation from vertical and reduce stick
-
out of wire to
3/8”
or less. If this still does not help, reduce the wire
speed. Some spatter is normal, though it should be minimal overall.
The wire can also pop and spatter if the voltage is too low for the wire
speed and/or wire diameter. This is mostly observed as flying bits of red
-
hot but un
-
melted wire, along with popping as the wire inconsistently
stubs into the puddle. This is followed by the wire pushing back against
your hand pressure while the wire visibly turns white/red hot before burn-
ing off. Too low of voltage will also produce a high piled bead with the
toes (edges) of the weld not properly wetting in resulting in poor fusion.
Even though the PowerSet feature has been provided, sometimes addition-
al adjustment may need to be made based off of welding position or joint
type. With this unit, we
’
ve tried to provide plenty of adjustment range in
the PowerSet function. Normally, this will still allow a functional setting.
However, when the welding wire is pushed to its maximum limits with
Volts and Wire Speed limit, welding may not be smooth and spatter, un-
dercut, and burn back (when the wire melts back to the tip) may occur.
Starting the Arc and Welding In the MIG Process.
Starting the arc is a relatively simple process. Before beginning, the wire
should initially be trimmed to between 1/4 to
3/8”.
Once the wire is
trimmed, the gun should be firmly grasped to prevent a phenomenon
often referred to as
“
machine gunning
”.
A light grasp, especially at start,
can cause the arc to stutter as the wire pushes back on the gun, lengthen-
ing the wire stick
-
out and creating an irregular start and a porous weld.
The end of the wire should be positioned just barely above the metal when
the trigger is pulled for the cleanest start. This will position the end of the
contact tip about
1/2”
above the weld. The gun should be in the vertical
position, with no more than 5 degrees lean in either side to side direction.
Holding the wire too far off from the metal will result in rough starting and
too long of wire stick out.
Once the arc has been established, the gun can then either be pushed or
pulled in the direction of the weld. In either case, the gun nozzle should
be positioned directly over the weld without angling the wire to one side or
the other of the weld as already mentioned. The gun should have no more
than 15 degrees lean pointed into (push) or pointed away from (pull) the
direction of travel. In most cases a push motion is desired. However, a
lot of texts offer conflicting information on whether to push or to pull the
gun. In reality, both are correct if used correctly and with each having
particular strength and weakness. Either one done with too much gun
angle will result in undesirable results. Most open
-
minded people who are
Explanation of MIG Functions and Terms
