Impax IM-TIG200 Instruction Manual page 36

TIG OPERATION
Remote Control Operation
If using a remote control current device connect
it to the socket on the front of the machine.
If you are using a foot pedal you must press the
Panel/Remote selector button to REMOTE mode
The term "minimum" refers to a foot pedal in the
"up" position, as it would be with no foot
pressure. "Maximum" refers to a fully depressed
Foot pedal.
When the welder is in TIG mode activating the
foot pedal energizes the electrode terminal and
varies the output welding current from its
minimum value of 10 Amp (DC), to the maximum
value set by the current control dial on the
control panel. This helps eliminate accidental
high current damage to the work piece and/or
tungsten, and provides a fine control of the
current.
When the welder is in the stick mode a remote
control has no effect and is not used.
It is important to note that, in some cases, the
tungsten will not start an arc at the minimum
current because the tungsten may be too large
or cold. To start an arc reliably, it is important to
depress the foot pedal far enough so that the
machine output current is near the tungsten
operating range.
To start the arc, the operator may have to turn
the current control up and depress the foot
pedal approximately 1/4 of the way down.
Depressing the foot pedal to its minimum
position may not start the arc. Also if the current
control is set too low, the arc may not start. In
most cases, a large or cold tungsten will not
readily establish an arc at low currents. This is
normal.
TIG (GTAW) Basic Welding Guide
Gas Tungsten Arc Welding (GTAW) or TIG
(Tungsten Inert Gas) as it is commonly referred
to, is a welding process in which fusion is
produced by an electric arc that is established
between a single tungsten (nonconsumable)
electrode and the work piece. Shielding is
obtained from a welding grade shielding gas or
welding grade shielding gas mixture which is
generally Argon based. A filler metal may also
be added manually in some circumstances
depending on the welding application.
Tungsten Electrode Current Ranges
Electrode diameter (mm)
1.0mm
1.6mm
2.4mm
3.2mm
4.0mm
4.8mm
Guide for Selecting Filler Wire Diameter
Filler Wire Diameter
1.6mm
2.4mm
3.2mm
4.8mm
DC TIG Welding
The TIG (Tungsten lnert Gas) welding process is
based on the presence of an electric arc
between a non-consumable electrode (pure or
alloyed tungsten with an approximate melting
temperature of 3370°C) and the workpiece. An
inert gas (typically argon) atmosphere protects
the weld pool.
To avoid inclusions of tungsten in the joint, the
electrode should not contact the workpiece. For
this reason the arc is started through a Hi. Freq.
generator.
For situations requiring no Hi. Freq., Touch Start
Tig reduces the short-circuit current to keep
tungsten inclusions to the minimum.
To improve weld bead quality at the end of the
weld it is important to carefully control the
downslope of current and ensure proper gas
coverage over the weld.
35
DC Current (A)
30-60
60-115
100-165
135-200
190-280
250-340
DC Current
Range (Amps)
20-90
65-115
100-165
200-350