Tweco PCM - 102 Machine Torch - Manual (Page 30)

OPERATION 4-6 Manual 0-2818
4.08 Machine Torch Operation
A. Cutting With Machine Torch
The machine torch can be activated by remote control
pendant or by a remote interface device such as CNC.
1. Use a square to check that the torch is perpendicu-
lar to the workpiece to obtain a clean, vertical cut .
A-02585
Workpiece
Square
Pinch Block
Assembly
Figure 4-6 Checking Alignment
2. To start a cut at the plate edge, position the center
of the torch along the edge of the plate (refer to
Figure 4-7).
B. Travel Speed
Proper travel speed is indicated by the trail of the arc
which is seen below the plate ( Figure 4-7). 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 alumi-
num.
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 direc-
tion as torch travel. Generally recommended for
Nitrogen plasma.
Standoff Distance
Straight Arc
Trailing Arc
Leading Arc
Direction of Torch Travel
A-02586
Figure 4-7 Machine 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 trans-
fer.
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 Slowdown adjustments that
may be required.