USER MANUAL
Torch to work distance can impact granularity
Negative cut angle: torch too low, increase torch to work distance.
Positive cut angle: torch too high, decrease torch to work distance.
Note: A slight variation in cut angles may be normal, as long as it is within tolerance.
The ability to precisely control the cutting height in such a hostile and ever-changing environment
is a very difficult challenge. Fortunately, there is a very linear relationship between Torch height
(Arc length) and arc voltage as this graph shows.
This graph was prepared from a sample of about 16,000 readings at varying cut height and the
regression analysis shows 7.53 volts per mm with 99.4% confidence. In this particular instance
this sample was taken from an Everlast 50 amp machine.
Torch voltage then becomes an ideal process control variable to use to adjust the cut height.
Let’s just assume for simplicity that voltage changes by 10 volts per mm. This can be restated to
be 1 volt per 0.1mm (0.04”). Major plasma machine manufacturers (e.g. Hypertherm, Thermal
Dynamics and ESAB), produce cut charts that specify the recommended cut height and estimated
arc voltage at this height as well as some additional data. So, if the arc voltage is 1 volt higher
than the manufacturers specification, the controller simply needs to lower the torch by 0.1 mm
(0.04”) to move back to the desired cut height. Neuron torch height control unit is used to
manage this process.
Arc OK Signal
Plasma machines that have a CNC interface contain a set of dry contacts (e.g. a relay) that
close when a valid arc is established and each side of these contacts are bought out onto pins on
the CNC interface. A plasma table builder should connect one side of these pins to field power and
the other to an input pin. This then allows the Neuron controller to know when a valid arc is
established and also when an arc is lost unexpectedly.
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