Tweco PCM-120 Machine Torch - Manual (Page 26)

OPERATION 4-6 Manual 0-2698
A-02202
Shield Cup
Torch
Standoff
Distance 1/8" - 3/8"
Figure 4-7 Standoff Distance
3. With the torch in starting position, lower the weld-
ing helmet, then press and hold the control switch.
After an initial gas purge, the pilot arc will come
on and remain on until the cutting arc starts.
4. Once on, the main arc remains on as long as the
control switch is held down, unless the torch is
withdrawn from the work or torch motion is too
slow. If the cutting arc is interrupted, the pilot
arc comes back on automatically.
5. To shut off the torch simply release the thumb con-
trol switch. When the switch is released a ten sec-
ond post-flow will occur. If the torch switch is
closed during the post-flow, the cutting arc will
restart immediately when the torch is brought
within range of the workpiece.
B. Piercing With Hand Torch
1. The torch can be comfortably held in one hand or
steadied with two hands. Choose the technique
that feels most comfortable and allows good con-
trol and movement. Position the index finger or
thumb to press the control switch on the torch
handle.
2. Angle the torch slightly to direct blowback par-
ticles away from the torch tip (and operator) rather
than directly back into it until the pierce is com-
plete.
3. In a portion of the unwanted metal start the pierce
off the cutting line and then continue the cut onto
the line. Hold the torch perpendicular to the work-
piece after the pierce is complete.
4. 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 mini-
mize the amount of scale which adheres to it.
C. Standoff Shield Cup With Straight Edge
The standoff shield cup can be used with a non-con-
ductive straight edge to make straight cuts by hand.
The standoff shield cup functions best when cutting
relatively smooth metal surfaces that are solid.
WARNING
The straight edge must be non-conductive.
A-02203
Non-Conductive
Straight Edge
Cutting Guide
Crown Shield
Cup
Torch
Standoff
Distance 1/8"
Figure 4-8 Using Standoff Shield Cup With Straight
Edge
4.08 Machine Torch Operation
A. Cutting With Machine Torch
The machine torch can be activated by remote con-
trol pendant or by a remote interface device such as
CNC.
1. Use a square to check that the torch is perpen-
dicular to the workpiece to obtain a clean, verti-
cal cut.