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PLASMA CUTTING TECHNIQUE
Using a plasma cutter is a skill that requires time and effort
to do well. Practice striking and maintaining an arc on
scrap work pieces before beginning work. This will help
you gauge the best settings for the plasma cutter for the
material at hand.
1. You can cut metal that will conduct electricity up to
approximately 1/2" thick mild steel or equivalent. Very thin
or very thick metals are more difficult to cut cleanly.
2. Generally set the air pressure between 60 and 80 psi.
Increased air pressure will increase plasma speed and
cutting pressure. Air pressure and amperage should be
adjusted in tandem.
3. Generally start with a mid-range amperage setting
(32-33 amps) and adjust up or down from there. Increased
amperage will increase cutting heat. This is needed with
heavier and harder metals. However, increased amperage
will reduce Duty Cycle time. (See page 7.)
4. Move the cutting head more slowly for thicker and
harder metals, and more quickly for thin or soft metals.
Keep the cutting head moving while cutting.
How do Plasma Cutters Work?
Plasma cutters work by feeding an inert gas (air) through
an electric arc. The air is then heated to an extremely high
temperature which converts the gas to plasma which cuts
the metal.
High temperature and pressure are required to create a
plasma. The electric arc provides the temperature, and by
exhausting the air through a very small orifice, the pressure
is increased far beyond the 60-80 PSI operating pressure
of the air supply.
What is Plasma?
Materials in Nature exist in one of four different states:
Solid, Liquid, Gas or Plasma. Plasma is very rare on Earth
because of its very high temperature; however most of
the matter in the universe is plasma. The Sun, stars and
galaxies are made of plasma. On Earth, you will find plasma
in lightening and a few other places. Neon tubes and
florescent lights contain low-temperature plasma when
lighted.
The difference between water ice, liquid water and water
vapor is temperature. In each of these states, temperature
energy pushes the molecules of water away from each
other to change the water is in. At very high temperature
and pressure the water molecules themselves break apart,
and the atoms begin to ionize. Normal atoms are made up
of protons and neutrons in the nucleus, surrounded by a
cloud of electrons. In plasma, the electrons separate from
the nucleus. The electrons are negatively charged, and
they leave behind their positively charged nuclei which
are known as ions. When the fast-moving electrons collide
with other electrons and ions, they release vast amounts of
energy. This energy is what gives plasma its unusual status
and great cutting power..
How do Plasma Cutters Work?
Plasma cutters work by sending a pressurized gas through
a small channel. In the centre of this channel, there is a
negatively charged electrode. When power is supplied to
the negative electrode, and the tip of the nozzle contacts
the work metal, the connection creates a circuit. When the
nozzle is lifted away, the arc will continue. As the inert gas
passes through the channel, the arc heats the gas until it
becomes ionized. This reaction creates a stream of directed
plasma, approximately 30,000°(16,649°C) and moving at
approximately 20,000 feet per second (6,096 m/sec),that
reduces metal to molten slag.
The plasma itself conducts electrical current. The cycle
of creating the arc is continuous as long as power is
supplied to the electrode and the plasma stays in contact
with the metal that is being cut. In order to ensure this
contact, protect the cut from oxidation, and regulate the
unpredictable nature of plasma, the cutter nozzle has a
second set of channels. These channels release a constant
flow of shielding gas around the cutting area. The pressure
of this gas flow effectively controls the radius of the plasma
beam.
MAINTENANCE
WARNING! Make sure the Power Switch of the Plasma
Cutter is in its "OFF" position and that the tool is
unplugged from the electrical outlet before performing
any inspection, maintenance, or cleaning procedures.
Before each use, inspect the general condition of the
Air Plasma Cutter. Check for loose cable connections,
misalignment or binding of the fan, cracked or broken
parts, damaged electrical wiring, and any other condition
that may affect its safe operation. If abnormal noise or
vibration occurs, have the problem
1. Corrected before further use. Do not use damaged
equipment.
2. Periodically recheck all nuts, bolts, and screws for
tightness.
3. Periodically blow the dust from the cooling vents with
compressed air.
4. Verify that the cooling fan is operational before cutting.
5. If the unit repeatedly shuts down from thermal overload,
stop all use. Have the Air Plasma Cutter inspected and
repaired by a qualified service technician.
6. Store the welder and accessories in a clean and dry
location.
7. Periodically disassemble and clean the Torch Head
components with steel wool. Replace burnt, cracked,
distorted, or coated components, Refer to the assembly
drawing on page 11.
8. To gain access to the internal components of the unit,
remove screws from Main Body Cover. The home user is
strongly advised not to remove the tool covers and not
to attempt any electronic repairs. Any repairs must be
completed by a qualified technician. Opening the tool
will void any warranties, and may result in damage to
equipment or possible personal injury. Don't do it.
9. On a daily basis check for any of the following problems:
If any are found, take the tool to a qualified repair
technician.
Page 7
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