Lincoln Electric IM467 SQUARE WAVE TIG 355 - Manual (Page 29)

WELDING OPERATION
INITIAL START-UP
Be sure the Square Wave TIG 355 has been installed
correctly with respect to location, high frequency pro-
tection, input power, and output connections.
If you are TIG welding, connect a K870 or K963
Amptrol or a K814 Arc Start switch to the Remote
Receptacle. Check that the gas supply is on. Check
for the correct type and size of tungsten electrode, gas
cone size and torch size. If you are using a water
cooled torch, check that the water supply is on.
Press the Start (green) Power pushbutton. The input
contactor will pull in, the pilot light will come on, the
meter displays will light up, and the fans will start. In
TIG mode, the gas and water valves will open for one
Afterflow period to purge the lines. The ammeter will
display the preset current (if there is no load on the
welder output terminals). The voltmeter will read zero
in TIG mode, or from 60 to 70 in STICK mode.
Select the Electrode Polarity needed (DC-/AC/DC+) .
Set the controls by going from left to right across the
top row and then the bottom row, choosing the correct
setting for each. Note that the bottom row of controls
includes on/off switches to easily lock out the controls
within blocks (Spot, Start, Pulse, or Crater Fill) without
changing the settings. Also, note that some of the
controls are automatically locked out internally if they
do not apply in STICK mode or do not apply in TIG
mode. This reduces the number of controls which
must be set. See Table B.1 for examples of the effects
of the Function controls on TIG welding.
STICK WELDING
1. Remove the Amptrol or Arc Start switch from the
Remote Receptacle.
2. Turn the welder on. The pilot light on the front
panel indicates when the power is on.
3. Select LOCAL current control;
Select STICK mode. (High Frequency switch has
no effect in STICK mode.)
4. Preset the current with the Current control and the
Ammeter.
5. Set the desired Arc Force. (See CONTROLS AND
SETTINGS, item 11, “Arc Force.”) (The Wave
Balance and Afterflow controls have no effect in
STICK mode.)
6. Turn the Start switch OFF, or set the START con-
trols for a hot start if needed. (See CONTROLS
AND SETTINGS, item 14, “Start Controls.”)
7. Strike an arc and weld. (There will be a buzzing
sound from the arc if you are AC welding, due to
the faster rate of current reversal of the Square
Wave.
TIG WELDING GUIDELINES
Recommended tungsten electrode sizes, stickouts,
currents, cup or nozzle sizes and gas flow are shown
in Table B.2. SINCE TIG APPLICATIONS CAN VARY,
THIS TABLE IS INTENDED AS A GUIDE ONLY.
Aluminum Welding: Set the Electrode Polarity switch
to AC, the High Frequency switch to CONTINUOUS,
and the Mode switch to TIG. Make all other control
settings to suit the size tungsten and current. In gen-
eral, pure or zirconiated tungsten electrode is best for
aluminum and should have a “balled” end not exceed-
ing the diameter of the tungsten. A buzzing sound will
occur in the arc when AC TIG welding aluminum. We
recommend that you set the AC Wave Balance control
to the Auto Balance position. For more information
see CONTROLS AND SETTINGS, item 8, “AC Wave
Balance.”
Stainless or Mild Steel Welding: Set the Electrode
Polarity switch to DC-, the High Frequency switch to
START, and the Mode switch to TIG. In general, 1% or
2% thoriated tungsten electrode is best for stainless or
mild steel and should have the end ground to a point.
If there is difficulty starting the arc, the tunsten may be
contaminated, or it may be too large to get up to oper-
ating temperature.
Note: Starting difficulties may often be due to not
pressing the Amptrol far enough. When the
Amptrol is just “cracked,” the minimum current
(2 amps) is produced. Pressing the Amptrol
more at the start of the weld will often solve
starting problems.
OPERATION
B-14 B-14
SQUARE WAVE TIG 355