Tweco A80-A120 CutMaster - Manual (Page 33)

CUTMASTER A80, A120
Manual 0-5119 OPERATION
4T-1
SECTION 4 TORCH:
OPERATION
4T.01 Machine and Automated Torch
Operation
Cutting With Machine or Automated Torch
These torches are activated by remote control pen-
dant 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 direc-
tion 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.
Standoff Distance
Straight Arc
Trailing Arc
Leading Arc
Direction of Torch Travel
A-02586
Automation and 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 pro-
duced 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, slow-
ing 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.
Piercing With Machine or Automated Torch
To pierce, 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 begins, 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.