Instructions / Assembly

23
GMAW
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Tandem Torch Alignment and Contact Tip to Work
D
istance
Sheet Metal Applications
C
entral to the successful operation of tandem GMAW is an
u
nderstanding of the set up of the special tandem GMAW
welding torch. In all cases, the central axis of the torch should
be normal to the weld joint. The lead arc has a built in 6° lagging
electrode angle, and the trail has a built in 6° leading electrode
a
ngle.
The CTWD for higher speed sheet metal type applications
should be set to 0.625” (16 mm). The electrode spacing is
critical, and the shorter CTWD establishes the correct spacing.
When the CTWD is held to this position the two arcs become
more distinct from one another, and shorter arc lengths are used
to provide higher travel speeds.
Heavy Plate Fabrication
The use of tandem GMAW for heavy plate fabrication requires a
longer CTWD, 1” (25 mm). The longer CTWD provides the cor-
rect spacing between the two arcs, and in this scenario, the arcs
tend to move very closely together. When held to the longer
CTWD the arcs lend themselves for use with much higher wire
feed speeds.
FIGURE 16: Tandem GMAW Torch Cutaway