4
SAFETY (Continued)
•
approved covers if unable to be moved from the welding area.
• Do not Plasma Cut closed containers such as tanks, drums, or pipes, unless they are
properly prepared according to the required Safety Standards to
vapors and substances are totally removed, these can cause an explosion even though the vessel
has been “cleaned”. Vent hollow castings or containers before heating, cutting or welding.
They may explode.
•
•
Be alert that cutting sparks and hot materials
from cutting can easily go through small cracks and openings to adjacent areas. Be aware that cutting
Gas Cylinders. Do not cut in the vicinity of pressurised gas cylinders or in the presence of explosive
dust, gases or fumes. Gas cylinders contain gas under high pressure. If damaged, a cylinder can
explode. Because gas cylinders are normally part of the welding process, be sure to treat them
carefully. CYLINDERS can explode if damaged.
• Protect gas cylinders from excessive heat, mechanical shocks, physical damage, slag,
sparks, and arcs.
• Insure cylinders are held secure and upright to prevent tipping or falling over.
• Never allow the plasma nozzle or earth clamp to touch the gas cylinder, do not drape welding cables
over the cylinder.
• Never plasma cut on a pressurised gas cylinder, it will explode and kill you.
• Open the cylinder valve slowly and turn your face away from the cylinder outlet valve and gas regulator.
equipment.
• Wearers of Pacemakers and other Implanted Medical Devices should keep away.
• Implanted Medical Device wearers should consult their doctor and the device manufacturer before going
near any electric welding, cutting or heating operation.
Noise can damage hearing. Noise from some processes or equipment can damage hearing.
This machine does not directly produce noise exceeding 80dB. The plasma cutting/welding proce-
dure may produce noise levels beyond said limit; users must therefore implement all precautions
required by law. Wear approved ear protection if noise level is high.
Hot parts. Items being plasma cut generate and hold high heat and can cause severe burns.
Do not touch hot parts with bare hands. Allow a cooling period before working on the plasma
torch. Use insulated welding gloves and clothing to handle hot parts and prevent burns.
11
BUILT TO GET THE JOB DONE
●
Air pressure and volume
Air pressure, flow rate and air quality are critical to quality plasma cutting and consumable life span.
The required air pressure and volume can vary from model to model and the manufacturer will provide the specs. The Shop Iron plasma
cutting machine air pressure is
requires a minimum of 6CFM and
The volume capacity of your compressor is
important, if you have a small compressor with exactly the same rating as the plasma, then the compressor will run continuously when you
are plasma cutting, a compressor with a l/min rating slightly higher than the plasma would be more adequate. If you are doing a lot of
cutting, cutting thick plate (same air consumption but slower cut speeds = longer cut time) then choose a compressor at 1.5 to 2 times the
plasma system requirement.
●
Technique Tips
●
Starting a cut
●
Hand torch cutting technique
Good air quality is essential to quality plasma cutting and consumable life span.
Compressors take in air at atmospheric pressure and increase the pressure and store it in a tank. Humidity in the air is condensed in the tank
and in the airlines producing water, more so in humid environments. Moisture that forms in air lines has a tendency to condense into larger
drops when the air pressure decreases as it is entering the plasma torch. When these droplets enter into the high temperatures (as much as
19832°f) in the plenum of the torch, they immediately break down into oxygen and hydrogen, which alters the normal chemical content of
air in the torch. These elements will then dramatically change the plasma arc which causes the torch consumable parts to wear very quickly,
alters the shape of the nozzle orifice, dramatically affecting cut quality in terms of edge squareness, dross formation, and edge smoothness.
Minimising the moisture in the air supply is absolutely critical to quality plasma cuts and longevity of consumable parts. As a minimum be
sure to drain the receiver (tank) on the air compressor at least daily. Most air plasma systems from reputable manufacturers have an on
board particulate filter and or a coalescing filter with an auto drain that will remove some moisture from the air supply. For home workshop
and light industrial users the on board air filter is adequate. Most situations however will require additional filtration to prevent moisture
from affecting the quality of the plasma cutter and in most cases it is recommended to install a sub micronic particulate filter that is
designed to trap water through absorption. This style of filter has a replaceable filter cartridge that absorbs water and must be changed
after it is near saturation, it should be installed close as possible to the air intake of the plasma cutter.
• It is easier to pull the torch through the cut than to push it.
• To cut thin material reduce the amperage until you get the best quality cut.
•
• For Straight cuts use a straight edge or cutting buggy as a guide. For circles,
use a template or circle cutting attachment.
• Check that the front end consumable parts of the plasma cutting torch
are in good condition.
Sub Micronic Filter example
Filter Element example
Hold the torch vertical at the edge of the work
piece
Pull the trigger to start the pilot arc.
The cutting arc will initiate when the torch tip
is close enough to the work piece. Start cutting
on the edge until the arc has cut completely
through.
Then, proceed with the cut.
When cutting make sure that sparks are exiting
from the bottom of the work piece.
If sparks are spraying up from the work piece,
you are moving the torch too fast, or you don't
have enough amps set.
Hold the torch vertical and watch the arc as it
cuts along the line.
Note: The dryer the air, the longer your consumable life!!
