So you want to purchase
a plasma cutter! It's kind of a bewildering
prospect to select a piece of equipment that is new
to you with so many manufacturers and models to
choose from.
Let 's approach the problem logically. To start
with, there are a number of questions that you must
answer for yourself, before you can go any further:
How many
hours a day do you plan to use your
plasma cutter? In other words, what
kind of duty cycle must it have?
What kind of electrical service do you
have where you intend to use the
machine? Is it 50 amp 220 volt single
phase? What other equipment will be
running simultaneously on the same
circuit?
What kind of portability must your
plasma cutter have? Will you be using
it exclusively in your shop, or will you
need to take it to the job? Do you have
a means of supplying the machine with
compressed air in remote locations? How
will you do that, with a portable
compressor or an air bottle? How will
you supply electric current at the site?
What kind of material do you plan to
cut, and how thick is it likely to be?
Will you be doing manual cutting
exclusively, or is there a possibility
that you may want to use your plasma
cutter with a CNC cutting machine?
What are your budget limitations? |
Generally speaking,
the higher the amperage output of the plasma cutter,
the greater the duty cycle is at lesser amperages.
In other words, if you plan to use the machine
around the clock, you should consider a larger unit
than you would need to cut the material you will be
working.
If you will be using your machine frequently, but
not continuously, consider a unit that is capable of
cutting the thickest material you are likely to
work. Most manufacturers provide duty cycle
information in their literature.
Many people make the mistake of thinking that the
greater the capacity of the machine, the better it
is. In general, fabricators consider oxy-fuel to be
superior to plasma for cutting steel when
thicknesses exceed about 1/2 inch. This is because
of the slight bevel (4 to 6 degrees) in the cut face
that plasma produces. It is not noticeable in
thinner materials, but becomes more so as
thicknesses increase. Also, at thicknesses above
1/2 inch, plasma has no cutting speed advantage over
oxy-fuel.
There is little point in buying a plasma cutter that
will cut 1 1/2" plate, if you are going to use
acetylene for such work anyway. If you are planning
to cut non-ferrous metals such as stainless or
aluminum, which cannot be cut by oxy-fuel, consider
a 50 to 80 amp. 220 volt plasma cutter.
If you plan to use your plasma cutter outside the
shop occasionally, you should consider one of the
new breed of semi-portable machines. These units
are little powerhouses that weigh less than 100
lbs., yet are capable of cutting 3/4" to 1" in a
pinch. You will need a bottle of air or a
compressor, and a hefty portable generator.
If you believe that you may automate your plasma
cutting at some point, you
must
select a unit that does not use a high-frequency
starting circuit. A high-frequency start acts
like a spark plug in a car. Rather than using
a relatively lower voltage pilot arc to initiate the
plasma process, it uses a high voltage spark.
This causes electrical interference such as locking
up the computer, destroying files, etc.
Like most other things in life, you get what you pay
for. Imported plasma cutters can be found on
the market for $800 or less. However, that is
money that could be put toward a modern inverter
type unit costing more initially, but less over time
when the cost of replacement parts and consumables
is factored in.
CUT 63 and 100 Amp Heavy duty plasma cutters
CUT 40 Plasma
cutter
If you do not print the
Direction to our office
you shall have difficulty finding us. |
