Tig Automatic Spot Welding In 2T And 4T Modes - Fimer TT255 AC/DC Manuel D'emploi

7.3 TIG AUTOMATIC SPOT WELDING IN 2T AND 4T MODES

In the machines which have this function it is possible to activate the automatic spot weld
function, with the single repetition mode (setting only this pot weld parameter) or multiple
repetition (setting the spot weld and pause parameter, for the machines which have these
features).
In the single repetition mode the machine keeps the arc on after it has been struck for a
period of time which is determined by the value of the spot weld parameter.
While the arc is on the machine executes the functions activated by the user (e.g. initial
current, ramp-up, pulsation) provided that the duration of these functions is compatible with
the duration of the spot weld set (e.g. if there is an initial current of 0.5s and a ramp-up of
1.0s, with the spot weld set to 0.5s only the initial current will flow; likewise with a weld of
0.8s duration the initial current will and a part of the ramp-up will be completed).
This function is generally available on machines with a welding program for TIG-Scratch,
TIG-Lift and TIG-HF modes.
The multiple repetition mode behaves exactly like the single repetition mode when the arc
is struck except that after the arc is switched off the machine strikes the arc again as long
as the torch button is kept pressed; the phases when the arc is on will have a duration
determined by the spot weld parameter, the phases when the arc is off will have a duration
determined by the Pause parameter.
This function is generally available on machines with a welding programme only for the
TIG-HF mode.
In 4t/4bilevel mode with spot weld activated the machine performs the functions set by the
user as if it were operating in 2t mode, in other words with the spot weld function active so
that there is only automation of the torch button (whereas in the mode with spot weld not
active the initial current continues until the button is released).
The figures below show graphs of the current with the automatic spot weld function in 2t
and 4t/4bilevel mode; the first impulse, shaded, is the only one performed if the spot weld
function is set to single repetition (value of the Pause parameter equal to 0), while all the
others are performed only if the spot weld function is set to multiple repetitions (value of
the Pause parameter not 0).
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