Lincoln Electric INVERTEC V205-T DC Operator's Manual page 23

V205-T DC & V205-T AC/DC
PROTECTIVE GAS
Both argon and helium work when welding aluminum. Argon is
preferred, due to its lower cost and consumption rate. This gas
also tends to stabilize the arc, thus making it easy to operate. For
some applications, however, the use of helium, or argon-helium
blends, is recommended due to better weld penetration and faster
travel speed. Helium is especially suitable for welding thick work-
pieces. The recommended gas flow rates are shown in table 5.
TABLE 5
Current (A)
50
100
150
200
250
300
TIPS FOR IMPROVED TIG STARTING
1. Start Current:
For the best AC or DC TIG starting characteristics it may be neces-
sary to adjust the start current on the front panel depending on the
tungsten size. In general, larger tungsten requires more energy to
establish an arc than smaller tungsten. As an initial guideline, set
the start current according to the following recommendations:
Tungsten Size (in.)
0.020, 0.040 1/16th
3/32 th
1/8th
2. DC Strike Current:
Aside from start current, DC strike current can also be adjusted
from the set-up menu to get a hotter or softer start when DC TIG
welding. Strike current is an initial spike of current that lasts a
few milliseconds before the machine goes to start current. In
general, the factory default of 40 amps works for most applica-
tions. If welding on very thin materials with small diameter tung-
sten, strike current can be turned down to minimize burning
through the weld material. Like wise for larger diameter tungsten
strike current can be turned up to put more energy in the tung-
sten.
Helium cfh-(l/min)
29 - (14)
29 - (14)
42 - (20)
42 - (20)
53 - (25)
53 - (25)
Start Current (Amps)
6-10 Amps
10-12 Amps
12-15 Amps
3. AC TIG Start Power:
For AC TIG welding AC start power can be adjusted from the set-
up menu to aid starting if required. The V205-T AC/DC when set
to AC TIG will try to initiate the arc with positive polarity until the
arc is established. Positive polarity puts more energy into heating
the tungsten but the drawback is that is can cause the tungsten to
ball excessively or to super heat. Note super heating of the tung-
sten can be noticed if the tungsten is glowing red or orange during
starting. Start Power can be adjusted within two ranges:
Range
0.5 to 1 Manual Setting
1.2 to 5.0 Incremental setting
If start power is set within the incremental range mode, the
machine tries to start electrode positive at a relative setting of 1. If
the arc fails to establish it will repeat the start sequence each time
by incrementing the amount of electrode positive energy by 10%
more (0.1) up to the start power limit setting or until the arc estab-
lishes. For comparison a start power limit of 2 if reached will have
twice the energy of the starting point of 1. If the tungsten has too
much of a ball on it or appears to be super heating during starts
the start power limit can be turned down. In the manual setting
range, the start power will not keep incrementing up to a limit.
Instead the start power stays at whatever level is set. For example
a setting of 0.5 will start the machine with half the normal starting
energy of 1.
B 9
OPERATION
Mode