WIA MC114-0, Руководство оператора

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Weldarc 200 AC/DC | Operator Manual | Model No MC114-2
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3.3.1.12 AC TIG Parameters
AC TIG mode is used for welding
Aluminium.
Arc Welding of Aluminium is difficult
because the metal readily forms an Oxide
layer, which is an electrical insulator, and
inhibits arc formation. The Oxide needs to
“cleaned off”.
Welding with Electrode positive will remove
the Oxide off the surface as the electrons
flow off the Aluminium to the tungsten
electrode. Continuous electrode positive
will burn the tip away, so the current has to
be reversed to electrode negative for some
of the time.
To achieve this an Alternating Current (AC)
for welding is required. The Alternating
Current has a FREQUENCY at which the
cycle changes positive to negative and also
a BALANCE of the proportion of positive
cycle to negative cycle.
The FREQUENCY and BALANCE can be
adjusted or set to AUTO setting where
predetermined settings are used by
the machine.
AUTO must be disabled before
FREQUENCY or BALANCE can be adjusted.
3.3.1.12.1 Balance
BALANCE is expressed as a % of the time
that the polarity is negative. Adjustment is
from 50-85%. For new clean aluminium an
AC BALANCE of 65-70% is a good
starting point.
Low % Balance
- Less time negative
- More time positive
- More cleaning action
- More heat in the tungsten
- Wider weld with shallower penetration
High % Balance
- More time negative
- Less time positive
- Less cleaning action
- Less heat in the tungsten, higher
current for smaller electrode
- Narrow weld beads
with deeper penetration
- Smaller heat affected zone
3.3.1.12.2 AC Frequency
When AC TIG mode is selected, then actual
AC frequency can be adjusted from 50
to 150Hz.
Higher frequency makes the welding
current change direction at a faster rate.
The arc becomes constricted, more stable
and directional providing deep penetrating
narrow welds.
Lower frequency the arc is wide with
shallow penetration, suitable for butt or
edge welds on thin material.
3.3.2 Machine Function
Press the Left hand button to activate the
Machine function selection.
Machine Functions: Selected shown
Highlighted.
Exit
Knob
Select
ON
VRD
OFF
VRD
Function
Parameter
DC TIG
+ +
% − % −