Tweco CutMaster 12mm - Manual (Page 39)

CUTMASTER 12mm
Manual 0-5076 OPERATION 4T-7
Standoff Distance
Straight Arc
Trailing Arc
Leading Arc
Direction of Torch Travel
A-02586
Mechanized Torch Operation
For optimum smooth surface quality, the travel speed
should be adjusted so that only the leading edge of the arc
column produces the cut. If the travel speed is too slow,
a rough cut will be produced as the arc moves from side
to side in search of metal for transfer.
Travel speed also affects the bevel angle of a cut. When
cutting in a circle or around a corner, slowing down the
travel speed will result in a squarer cut. The power source
output should be reduced also. Refer to the appropriate
Control Module Operating Manual for any Corner Slow-
down adjustments that may be required.
Piercing With Machine Torch
To pierce with a machine torch, the arc should be started
with the torch positioned as high as possible above the
plate while allowing the arc to transfer and pierce. This
standoff helps avoid having molten metal blow back onto
the front end of the torch.
When operating with a cutting machine, a pierce or dwell
time is required. Torch travel should not be enabled until
the arc penetrates the bottom of the plate. As motion be-
gins, torch standoff should be reduced to the recommended
1/8 - 1/4 inch (3-6 mm) distance for optimum speed and
cut quality. Clean spatter and scale from the shield cup
and the tip as soon as possible. Spraying or dipping the
shield cup in anti - spatter compound will minimize the
amount of scale which adheres to it.