Tweco Max 300 w-TD-750 - Manual (Page 21)

Manual 0-2557 15 INSTALLATION PROCEDURES
• Only clean, dry air is recommended for use as plasma
gas. Any oil or moisture in the air supply will sub-
stantially reduce torch parts life.
• Provides satisfactory results on non-ferrous materi-
als.
2. Nitrogen (N2) Plasma
• Provides better cut quality on non-ferrous materials
such as stainless steel and aluminum.
• Can be used in place of air plasma with air second-
ary or carbon dioxide (CO
2
).
• Provides much better parts life than air.
• A good clean welding grade nitrogen should be used.
3. Argon/Hydrogen (Ar/H2) Plasma
• Recommended for use on 3/4 in (19 mm) and thicker
stainless steel. Recommended for 1/2 inch (12 mm)
and thicker non-ferrous materials. Ar/H2 is not nor-
mally used for thinner non-ferrous materials be-
cause less expensive gases can achieve similar cut
quality.
• Poor cut quality on ferrous materials.
• Provides faster cutting speeds and high cut quality
on thicker materials to offset the higher cost.
• A 65% argon/35% hydrogen mixture should be used.
4. Oxygen (O
2
) Plasma
• Oxygen is recommended for cutting ferrous materi-
als.
• Provides faster cutting speeds.
• Provides very smooth finishes and minimizes ni-
tride build-up on cut surface (nitride build-up can
cause difficulties in producing high quality welds
if not removed).
B. Secondary Gases
NOTE
Refer to Section 2.03, Specifications & Design Fea-
tures, for proper gas pressure and flow rate.
1. Compressed Air Secondary
• Air secondary is normally used when operating with
air plasma and occasionally with nitrogen plasma.
• Improves cut quality on some ferrous materials.
• Inexpensive - reduces operating costs.
2. Carbon Dioxide (CO
2
) Secondary
• CO
2
secondary is used with nitrogen or Ar/H2
plasma.
• Provides good cooling and maximizes torch parts
life.
• Provides good cut quality on ferrous or non-ferrous
material.
• May reduce smoke when used with Ar/H2 plasma.
NOTE
When CO
2
is used as the secondary gas, twenty
(50 lb) cylinders must be manifolded together or a
bulk CO
2
system used to get the required flow rate
of 200 scfh. Shop compressed air is a good alterna-
tive if providing the required CO
2
flow rate is not
feasible.
3. Nitrogen (N2) Secondary
• Nitrogen secondary is used with Ar/H2 plasma.
• Provides smooth finishes on non-ferrous materials.
• May be used with nitrogen plasma in order to oper-
ate from one compressed gas cylinder - but torch
parts life may be shorter than with CO
2
secondary.
• May reduce smoke when used with Ar/H2 plasma.
4. Water Secondary
• Water secondary should be used only in mechanized
applications - never in hand cutting!
• Normally used with nitrogen, Ar/H2, or air plasma.
• Provides very smooth cut surface.
• Reduces smoke and heat input to the workpiece.
• Effective up to 1 inch maximum material thickness.
• Tap water provides low operating expense.
3.07 Gas Connection
A. Connection
Connect the gases to the Control Module as described
in the Control & Power Module Operating Manual
(0-2473) supplied with the Control Module. Water
secondary is connected to the Power Base Unit as de-
scribed in the Power Base Unit Operating Manual 0-
2474.
CAUTION
Air supply must be free of oil, moisture, and other
contaminants. Excessive oil and moisture may
cause double-arcing, rapid tip wear, or even com-
plete torch failure. Contaminants may cause poor
cutting performance and rapid electrode wear.
B. Checking Air Quality
To test the quality of air, place a welding filter lens in
front of the torch and turn on the gas. Any oil or mois-
ture in the air will be visible on the lens. Do not ini-
tiate an arc!