Tips for Improved TIG Starting

B-11	OPERATION	B-11

1. Start Current:

For the best AC or DC TIG starting characteristics it may be necessary to adjust the start current on the front panel depending on the tungsten size. In gener- al, larger tungsten requires more energy to establish an arc than smaller tungsten. As an initial guideline, set the start current according to the following recom- mendations:

Tungsten Size (in.)	Start Current (Amps)
0.020, 0.040 1/16th	6-10 Amps
3/32 th	10-12 Amps
1/8th	12-15 Amps

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 fac- tory default of 15 amps works for most applications. If welding on very thin materials with small diameter tungsten, strike current can be turned down to mini- mize burning through the weld material. Like-wise for larger diameter tungsten strike current can be turned up to put more energy in the tungsten.

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 Invertec® V311-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 tungsten can be noticed if the tungsten is glowing red or orange during starting. Start Power can be adjusted within two ranges:

Range

Mode

0.5to 1 Manual Setting

1.2to 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% (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.

STICK CRISP MODE DYNAMIC CURRENT REGULATION

When running E6010 electrodes DC Crisp mode is recommended. The Invertec® V311-T AC/DC has a special dynamic current regulation that is ideal for the whipping technique common to E6010 electrodes.The machine regulates the welding current based on changes in arc length. As the arc length is increased and the arc voltage increases, the machine will reduce its welding current below the set point. As the arc length is decreased and the arc voltage decreases the machine will increase its current.

FIGURE B.8

Set Point

Weld

Current


				Increase
		Decrease		Increase
		Arc Length		Arc Length

Average Arc Length

Arc Force Control – Arc Force is a setting that helps reduce sticking the electrode into the weld puddle. Increasing the arc force percentage will provide a higher boost of current when the electrode is about to short into the weld puddle. In Stick Crisp mode since the current is dynamically regulated based on the arc voltage, shorting the electrode to the work will be rare

-therefore, adjustments to the arc force percentage will not be as noticeable in Stick Crisp mode com- pared to Stick Soft mode.

Lincoln Electric IM10051 manual Tips for Improved TIG Starting

OPERATION