LIFT ARC IGNITION for TIG
(tungsten inert gas) Welding
gas flow
tungsten off
the work
Lay the nozzle on the job without the
tungsten touching the work.
Rock the torch sideways so that the
tungsten touches the work & hold
momentarily.
tungsten touches the work
4.2 TIG Welding Fusion Technique
Rock the torch back in the opposite
direction, the arc wil l ignite as the
tungsten lifts off the work.
arc ignition
Lift the torch to
maintain the arc.
established
TIG arc
Lift Arc is a form of arc ignition where the
machines has low voltage on the electrode
to only a few volts, with a current limit of one
or two amps (well below the limit that causes
metal to transfer and contamination of the weld
or electrode). When the machine detects that
the tungsten has left the surface and a spark is
present, it immediately (within microseconds)
increases power, converting the spark to a full
arc. It is a simple, safe lower cost alternative
arc ignition process to HF (high frequency) and
a superior arc start process to scratch start.
Manual TIG welding is often considered the
most difficult of all the welding processes.
Because the welder must maintain a short
arc length, great care and skill are required
to prevent contact between the electrode
and the work piece. Similar to Oxygen
Acetylene torch welding, Tig welding
normally requires two hands and in most
instances requires the welder to manually
feed a filler wire into the weld pool with one
hand while manipulating the welding torch
in the other. However, some welds combining
thin materials can be accomplished without
filler metal like edge, corner, and butt joints.
33
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