TIG HF/ Lift Ignition Modes (31,32)
For TIG welding process, contact of the torch tungsten to the workpiece will cause
contamination of the tungsten and the workpiece that will adversely affect the weld
quality, especially when the tungsten is electrically energised.
HF Ignition (High Frequency) sends a pulse of high energy electricity through the
torch system that is capable of ‘jumping’ between the tungsten and the workpiece,
ensuring arc starting without any contact between the tungsten and workpiece.
The disadvantage of HF ignition is that the high ener-
gy electrical pulse creates significant electrical and radio signal interference, which
limits its use around sensitive electronic equipment such as computers.
Lift TIG Ignition is a compromise that minimises tungsten contamination while
eliminating the electrical interference of HF start systems. Lift arc starting works by
lightly resting the tungsten on the work piece, activating the torch trigger signal and
then lifting the tungsten off. The control circuit will sense when the tungsten is
removed from the work piece and send a low powered pulse of electricity through
the tungsten that will cause the TIG arc to initiate. Because the tungsten is not ‘live’
when it is in contact with the work, contamination is minimised.
Program/Job Memory (34)
The welding machine has 9 memory/ job spaces that parameters can be saved to
for easy recall. To access a saved program, press and hold in the control knob (24)
and the program number 1-9 will show on the display, the ‘JOB’ indicator will be lit.
Adjust to the program number required by rotating the control knob. Once the
program is accessed, it will automatically load. To return to normal parameter
settings, press the control knob again (which will also load the selected program)
To save parameters set as a program, press and hold the control knob for a few
seconds and the display will blink. The settings are now saved in the last program
space that was selected. If setting parameters to save as a program, ensure that
you start with a program number that the data is OK to overwrite, as the previous
settings saved to that memory space will be lost.
Pulse welding
Pulse welding mode switches the welding output between a high and low current
output in a cyclical manner. When used correctly this function has substantial
benefits in the TIG welding process including greater weld penetration for less work
heat input and greater control of the weld pool.
The basic theory for setting the base current using pulse mode is that the base
current should be sufficient to maintain the existing molten weld pool, while the
peak current is sufficient to melt new metal in order to move/ expand the molten
weld pool. Increased pulse frequency will have the effect of making the arc more
tightly focused which is useful for fine stainless work and similar.
Pulsing can also be used to help move the weld pool, this technique is useful for
welding out of position or with materials that have higher viscosity weld pool. Higher
pulse duty setting will give greater heat input, while lower pulse duty will have the
opposite effect.
Содержание Grand Tig 200
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