Plasma is the fourth state of matter and also what CNC cutters use. To backtrack a little bit, plasma cutters in their simplest form are essentially a new way of cutting through metal without having to change anything about the tool. You can make clean cuts on any type of metal as long as you’re using a powerful enough cutter.
Pair that with CNC or computerised numerical controls and you have yourself a self-reliant plasma cutter that doesn’t require you to hold the tools itself. Instead, you only give it certain parameters and press a button to make it work. But things are not always as easy as they seem.
Setting up a CNC Plasma Cutter
Power
The first thing you need to consider when you are setting up a CNC plasma cutter is its power supply. No matter the size of the machine you shouldn’t overload the electrical installation in your workshop which can happen if you have a powerful CNC plasma cutting machine. Make sure your workshop’s panel board can hold up with the demands of the cutter.
Air
The next thing and probably the most straightforward one when it comes to setting up CNC plasma cutters is air supply. A constant supply of air is something every CNC plasma cutting table as it’s needed throughout the cutting process the same as with its power supply.
Ventilation
Plasma cutting creates fumes as it melts its way through metal workpieces. This is why a well-ventilated area is a must. You should have the fumes taken care of as soon as they leave the surface. This way you’ll make for a healthy working environment.
Using a CNC Plasma Cutter
Tools & Supplies
There are certain things you need to have before you start using a CNC plasma cutter. One of them is an air compressor that needs to drive air to the cutter as plasma cutters rely on compressed air. This is easy to fit though as the compressor connects to an air regulator at the back. You should also have the right type of nozzles on standby should you need to work on different metals and different material thicknesses.
Settings
There are certain settings that you need to set up according to what you’re going to be cutting. One of these settings is the amperage. The number of amps the torch works at affects how well it’s going to make the cuts. Usually, higher amp settings are going to cut thicker pieces of metal much better but on thinner workpieces, you can easily cause them to warp.
Air pressure is another setting you should be wary of before you start your CNC plasma cutter. While the majority of CNC plasma cutters have the air pressure pre-set that will make the machine work well no matter the amperage you can still adjust it anywhere between 90 and 100 PSI (6 and 7 bar) depending on the workpiece.
Travel speed is the last of the three and it’s going to be affected by the thickness of the material you’re working on. If at the correct travel speed, the torch should have the spark fly straight out the other side of the workpiece. When you’re cutting too quickly the spark will spray out at a steep angle in the direction opposite of your cutting. If cutting too slow then you will have the sparks bounce off the workpiece and you won’t be cutting it.
What Matters with CNC Plasma Cutters
Duty Cycle
The duty cycle of CNC plasma cutters refers to the number of minutes it can work for without the need for a break during a 10-minute period. For example, if you have a plasma cutter with a 70% duty cycle it means you get to use it for 7 minutes before it needs to cool down for 3 minutes. After those 3 minutes, you can use it for another 7 minutes and so on. A 100% duty cycle is ideal but it won’t always go hand in hand with the number of amps you need for your project(s).
Cutting Capacity
The cutting capacity or ability of a CNC plasma cutting table is determined by its amp rating. For instance, a 20A cutter is able to cut through material that is 3 mm thick and every added 10A adds an additional 3 mm of cutting capacity. The higher the amperage, the thicker the material you can cut but keep in mind that this won’t always make for the best duty cycle or the most efficient machine.
Power
Power is everything on a CNC plasma cutting machine as it affects everything else. Keep in mind though that a plasma cutter with a higher amp rating is going to consume more power. Typically a 40A cutter is able to provide a 100% duty cycle on material no thicker than 6 mm. Anything more than 40A is going to be quite powerful but keep in mind that cutters rated between 65A and 85A require more capable circuits too.
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