required, thicker material requires a more powerful arc with more heat so more current (amps) are
necessary to melt the material.
LIFT ARC IGNITION for TIG (tungsten inert gas) Welding
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.
3.3.4 TIG Welding Fusion Technique
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. This is known as Fusion welding where the edges of the metal pieces are melted together
using only the heat and arc force generated by the TIG arc. Once the arc is started the torch
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
Rock the torch back in
the opposite direction,
the arc will ignite as
the tungsten lifts off
the work.
arc ignition
Lift the torch to
maintain the arc.
established
TIG arc
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