Jasic EVO 2.0 EM-160C, Руководство оператора

Страница: 66 / 82

66
GUIDE TO TIG WELDING
Before starting any welding activity ensure that you have suitable eye protection and
protective clothing. Also take the necessary steps to protect any persons within the welding
area.
Lift TIG (lift arc)
Not to be confused with scratch start, this arc starting method allows the tungsten to be in direct contact
with the work piece first but with minimal current so as not to leave a tungsten deposit when the
tungsten is lifted and an arc is established.
With lift TIG, the open circuit voltage (OCV) of the welder folds back to a very low voltage output when
the unit senses it has made continuity with the work piece. Once the torch is lifted the unit increases
output as the tungsten leaves the surface. This creates little contamination and preserves the point on
the tungsten although this is still not a 100% clean process.
The tungsten still can get contaminated but
lift TIG is still a much better option than scratch starting, for mild and stainless steel although these
methods of arc starting are not a good option when welding aluminium.
The Jasic EVO EM range offers Lift TIG mode utilising the TIG torch switch operation mode which starts
the process with the internal gas valve opening to start the gas flow first.
Set the TIG welding current and other TIG welding parameters by using the control dial. (see page 19
onwards for further details)
LIFT TIG process
Press the TIG torch switch, then touch the tungsten electrode to the work piece for less than 2 seconds
and then lift away to 2
- 4mm from the work piece and the welding arc is then established.
Once welding is complete release the torch trigger to disengage the welding arc but ensure you leave
the torch in place to shield the weld with gas for a few seconds and then turn off the gas at the valve
on the torch head.
PLEASE NOTE:
•
When starting the arc if the short - circuit time exceeds 2 seconds the welder turns off the output
current, lift the welding torch tungsten away from the work piece and restart the process as above
to start the arc again.
•
During welding, if there is short circuit between tungsten electrode and the work piece, the welder
will immediately reduce the output current; if the short circuit exceeds 1 second, the welder will
turn off the output current. If this happens, the arc will need to be restarted as above and the
welding torch needs to be lifted to start the arc again.