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Plasma cutters work by passing an electric arc through a gas that is passing through a constricted opening. The gas can be air, ni-
trogen, argon, oxygen. etc. The electric arc elevates the temperature of the gas to the point that it enters a 4th state of matter. We
part of the circuit, the electrical conductivity of the plasma causes the arc to transfer to the work. The restricted opening (nozzle)
the gas passes through causes it to squeeze by at a high speed, like air passing through a venturi in a carburettor. This high speed
gas cuts through the molten metal.
Plasma cutting was invented as the result of trying to develop a better welding process. Many improvements then led to making
How a plasma cutter works:
Basic plasma cutters use electricity to superheat air into plasma (the 4th state of matter), which is then blown through the metal
to be cut. Plasma cutters require a compressed air supply and AC power to operate.
Operation:
electrode and through the hole of the cutting nozzle.
maintain aconstant current through the joint.) Electrons arc across the gap, ionizing and super heating the air
creating a plasma stream.
Notes:
The nozzle and electrode require periodic replacement. The electrode has an insert of tough high conductive material such as
longer life of electrodes and nozzles, in short clean dry air gives longer parts life, the cleaner and dryer the better. We recommend
use of a Plasma Air Filter.
What kinds of materials can the plasma cut?
Virtually any metal can be plasma cut including steel, stainless steel, aluminium, brass, copper, etc. Any thickness from 30 gauge
through 1
3/16
"
can be cut, depending on the power of the plasma cutter used.
How Does Plasma Cutting Compare to Oxy-fuel (gas) cutting?
Plasma cutting can be performed on any type of conductive metal - mild steel, aluminium and stainless are some
examples. With mild steel, operators will experience faster, thicker cuts than with alloys. Oxy-fuel cuts by burning, or
oxidizing the metal it is severing. It is therefore limited to steel and other ferrous metals which support the oxidizing
process. Metals like aluminium and stainless steel form an oxide that inhibits further oxidization, making conventional
oxy-fuel cutting impossible. Plasma cutting however does not rely on oxidation to work and thus it can cut aluminium, stainless
for the plasma gas. In most shops, compressed air is readily available, and thus plasma does not require fuel gas and compressed
oxygen for operation. Plasma cutting is typically easier for the novice to master, and on thinner materials, plasma cutting is much
faster than oxy-fuel cutting. However, for heavy sections of steel (1" and greater), oxy-fuel is still preferred since oxy-fuel is typi-
cally faster and, for heavier plate applications high powered plasma machines are required for plasma cutting applications.
What are the limitations to Plasma Cutting? Where is Oxyfuel preferred?
The plasma cutting machines are typically more expensive than oxy/acetylene. Also, oxy/acetylene does not require
access to electrical power or compressed air which may make it a more convenient method for some users. Oxyfuel can generally
cut thicker sections (>63/64 inch) of steel more quickly than plasma
Electrode
Nozzle
Plasma Stream
Electrode Insert
Shield Cup
AIR PLASMA CUTTING TECHNOLOGY
BUILT TO GET THE JOB DONE
5) Correct amperage and travel speed are
important and relevant to material thickness
and are correct when sparks are exiting from
the work piece.
If sparks are spraying up from the work piece
travel speed is too fast.
6)
seconds to cool the torch head.
2) Connect the Earth Clamp securely to the
work piece or the work bench.
3) Place and hold the torch vertical at the
edge of the plate
4) Pull the trigger to energise the pilot arc.
The cutting arc will start when the nozzle is
moved closer to the edge of the work piece.
When the cutting arc has cut through the
edge of the plate start moving evenly in the
direction you wish to cut,
1) Wear your safety gear. Generally you want the same
type of protective gear as when welding. Plasma has
high arc voltage if the job or bench is wet and you place
your hand or arm on it you can become part of the cir-
cuit and receive a shock, be sure you are wearing leather
gloves, Full lenght pants and covered shoes, Wear eye
protection a #5 shade is the minimum eye protection
with other shades required depending on amperage. A
face shield is also recommended,
especially suitable if your hands are unsteady, or if you wish to use a straight edge guide or
pattern guide. It also helps extend tip life.
Cut Quality
A clean cut depends on several factors:
●
amperage
●
travel speed
●
tip height & position
●
tip and electrode quality
●
air pressure and quality
●
technique
The best quality cut will be produced when all these variables are set correctly for the material thickness and type
of material being cut.
Poor quality cut
Good quality cut
Please note: Torch handle and shape varies from Machine to
Machine.
