Making A Cut; Tuning-In The Air Pressure; Torch Movement Rate; Typical Cutting Problems - Century Tool 118-009 User Manual

2. It is best to position the torch so that the nozzle is
at or near a 90 degree angle (perpendicular) to the
workpiece (see Figure 12).
3. Although it is acceptable for the nozzle to touch
and be dragged along the workpiece, consumable
life will be extended if a gap of no more than 1/16"
can be maintained between the nozzle and the
workpiece while cutting. When cutting thicker
materials, maintaining a 1/16' gap will provide a
cleaner cut. Use the torch standoff (optional on 20
A models) attachment to maintain the spacing.

MAKING A CUT

DO NOT ATTEMPT TO CUT until you have read and
understand the entire SAFETY SUMMARY. The
SAFETY INFORMATION is there to help you to know
how to reduce the risks of DEATH or INJURY to
yourself or bystanders in the cutting area, and even
from PROPERTY DAMAGE in the vicinity of the cutting
area.
1. Position the torch at the edge of the workpiece
over the point where you want the cut to start.
2. Lower welding helmet, goggles, or position shield
to protect eyes.
3. Press the trigger on the cutting torch and the
plasma arc will start. If the arc blows itself out,
follow the air pressure tune-in procedure below.

TUNING-IN THE AIR PRESSURE

1. Set mode switch to SETUP.
2. Decrease the air pressure by one psi (unless you
have reached 61 psi in which case, see CUTTING
PROBLEMS).
3. Set the mode switch to RUN.
4. Return to step A above and try a new cut. If you
reach the lowest acceptable pressure setting of 61
psi and the arc continues to blow out, see
CUTTING PROBLEMS.
5. When the plasma arc has cut through the entire
thickness at the edge of the workpiece, begin to
move the torch.
6. Release the trigger on the torch when you wish to
stop cutting.

TORCH MOVEMENT RATE

The torch movement rate is the speed at which the
torch is moved along the work piece and depends on
several factors such as the type and thickness of the
material being cut and the comfort or ability of the
operator to follow the desired cut line. It is important
that the rate of movement be slow enough that the
plasma arc cuts all the way through the work piece or
life expectancy for the consumables will be drastically
reduced.
The best procedure for determining the proper cutting
speed is to spend some time cutting on various types
and thicknesses of materials and observing the results
of different rates of travel and angles of cut.
As a starting point, see the cutter speed charts in
Figure 13 and Figure 14 for approximate torch
movement rates.
190
180
170
160
150
140
130
120
110
100
90
80
70
60
50
40
30
20
10
0
0 1/16" 1/8"
Material Thickness
Figure 13. 20 Amp Cutter Speed Chart
200
175
150
125
100
75
50
25
0
1/8 3/16
18 16 14
GA GA GA MATERIAL THICKNESS
Figure 14. 50 Amp Cutter Speed Chart

TYPICAL CUTTING PROBLEMS

There are two main problems that can occur during the
cutting operation.
1. The cut is not penetrating the material being
worked on.
a. Torch movement rate is too fast.
b. Nozzle is not being held perpendicular (at 90
degrees) to the work piece.
c. The torch being held too far from work piece
(should be about 1/16 inch).
d. Attempting to cut material that is too thick.
e. Using worn out nozzles or electrodes.
f. Using the incorrect nozzle for the amperage
selected (50 Amp cutters ONLY)
2. The cutting arc is breaking up or quitting
altogether during cutting.
a. Worn out nozzle and/or electrode.
b. Low line voltage.
c. Air pressure setting is too high.
Mild Steel
Aluminum
3/32" 1/4" 5/32" 3/8"
TYPICAL PERFORMANCE
(MILD STEEL)
30 AMP
40 AMP
50 AMP
1/4 5/16 3/8 7/16 1/2
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