ESAB Knowledge center.
What is plasma process control?
April 8, 2013
And what’s the difference between manual and automatic controls?
Plasma process control is simply the method used to control all of the settings required to run the plasma cutting process equipment, such as gases, current, arc voltage, cutting speed, etc. Plasma shape cutting on a CNC machine can be done with a wide variety of plasma torches and systems, from the simplest hand-held torches, like on a PlasmaCam machine, to the most advanced systems like ESAB’s m3 automatic plasma system.
In a simple system, gas control usually consists of a single solenoid valve that opens, with the gas flow based on the input pressure set at an external regulator. But even on such simple systems you still need to set the correct cut speed, pierce time delay, kerf offset, and height control voltage. More complex manual systems may have many different knobs, dials, and switches that all have to be set properly before you start cutting.
On advanced systems with automatic gas controls, there could be as many as 40 or 50 different parameters and settings that need to be adjusted every time you change to a different thickness, material type, or nozzle. It’s way too time consuming and error prone for an operator to make all of those adjustments manually. In addition, there are lots of settings that need to change quickly during or after piercing, or near the end of the cut, which can’t be done manually.
That’s why automatic plasma process control was invented – to automate setup and control of all of the parameters needed to run a modern CNC plasma cutting machine, so the operator doesn’t have to do it manually. With an automatic process control, the operator’s job is simplified because he doesn’t have to look up or remember all of the settings. He only has to select the correct parameter set, usually based on the material type and thickness that he needs to cut.
Integrated Plasma Process Control
A plasma process control can be a micro computer built into a power supply. In that case, the operator goes to the plasma power supply and selects the parameter set there. It could also be integrated within the CNC, in which case the operator selects the parameter set right at the machine’s control console. Stand alone systems can also be controlled by the CNC through a pre-defined interface that selects a parameter package, but a plasma process control integrated into the CNC is more powerful and can do things that a stand alone system can’t do. For example, stand alone systems are usually limited to a single set of parameters that have to be selected prior to starting the cut, and therefore can’t be changed during the cut. By comparison, a system integrated with the CNC can change parameters on the fly to coordinate with the part program.
A good example of how an integrated system is more powerful is ESAB’s Precision Hole Technology, which automatically changes parameters when cutting small holes, and can change parameters many times duiring a nest, providing best cut quality in every situation as required by the nest or shape. CNC integration also enables other advanced capabilities, such as Smart Voltage Height Control, LiveView Process Control, and advanced diagnostics.