Tweco 102 Cutmaster - Manual (Page 41)

CUTMASTER 102
Manual 0-4997 OPERATION 4T-7
Standoff Distance
The tip to work distance affects gouge quality and depth.
Standoff distance of 1/8 - 1/4 inch (3 - 6 mm) allows for
smooth, consistent metal removal. Smaller standoff dis-
tances may result in a severance cut rather than a gouge.
Standoff distances greater than 1/4 inch (6 mm) may result
in minimal metal removal or loss of transferred main arc.
Slag Buildup
Slag generated by gouging on materials such as carbon and
stainless steels, nickels, and alloyed steels, can be removed
easily in most cases. Slag does not obstruct the gouging
process if it accumulates to the side of the gouge path.
However, slag build - up can cause inconsistencies and
irregular metal removal if large amounts of material build
up in front of the arc. The build - up is most often a result
of improper travel speed, lead angle, or standoff height.
4T.06 Mechanized Torch Operation
Cutting With Mechanized Torch
The mechanized torch can be activated by remote control
pendant or by a remote interface device such as CNC.
1. To start a cut at the plate edge, position the center of
the torch along the edge of the plate.
Travel Speed
Proper travel speed is indicated by the trail of the arc which
is seen below the plate. The arc can be one of the following:
1. Straight Arc
A straight arc is perpendicular to the workpiece surface.
This arc is generally recommended for the best cut using
air plasma on stainless or aluminum.
2. Leading Arc
The leading arc is directed in the same direction as torch
travel. A five degree leading arc is generally recommended
for air plasma on mild steel.
3. Trailing Arc
The trailing arc is directed in the opposite direction as
torch travel.
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.