SPT SPARCIN 9, Instructions For Use Manual

Page: 7 / 32

7
SPARCIN 9 / SPARCIN 9C
4. GENERAL INFORMATION ON PLASMA CUTTING
With exception of the systems that have built-in compressors (SPARCIN 9C), all SPT
Plasmateknik AB manufactured plasma cutting systems with water cooled torch have full
multi-gas capability.
When using technical gases, a pressure regulator as opposed to a flow regulator must be fitted
to the gas cylinder. The use of flow regulators may lead to ignition problems and torch
malfunction.
This chapter also describes in general how to optimise cutting quality and consumable
lifetime.
When to use technical gas
Mild steel
Mild steel is cut with good quality using air as plasma generating gas. In some applications
however, when better cut quality is desired, pure oxygen can be used as plasma generating
gas.
When cutting with oxygen the consumable lifetime is shorter than with air.
Stainless steel
Most types of stainless steel are cut with good result with air as plasma generating gas. The
weldability of the kerf however may be improved by using a technical gas.
Using pure nitrogen as plasma generating gas you can reduce the amount of chrome-oxide in
the kerf. When cutting with nitrogen, the gas electrode as well as the air electrode may be
used.
To further improve the kerf quality, a mixture of 10% hydrogen in nitrogen (NH10) may be
used. Since this mixture contains hydrogen a tendency to develop dross may occur. This can
be minimised if not eliminated by very precisely adjusting cutting parameters as speed,
distance, gas flow, nozzle size, process power etc. When cutting with NH10 the gas electrode
as well as the air electrode may be used.
Aluminium
There are a great number of different aluminium alloys available. Most of them are cut
without dross and with high speed using air as plasma generating gas. The aluminium-oxide in
the kerf may reduce the weldability of the cut.
To reduce the aluminium-oxide a gas mixture of 10% hydrogen in nitrogen (NH10) may be
used. When cutting with NH10 the gas electrode as well as the air electrode may be used. To
further reduce the aluminium oxide a mixture of 35% hydrogen in argon (AH35) may be used.
When cutting with AH35 the gas electrode must be used.
Note that when cutting with AH35 it may be necessary to use a nozzle with a bigger orifice to
prevent double arcing.