Plasma is one of the four states of matter, along with liquid, gas, and solid. It’s technically a type of gas, but an ionized gas full of positive ions. This allows the plasma to become electrically conductive. The gas that carries electricity is then what’s called plasma.
Plasma cutting involves using that gas to cut metal. The nozzle of the cutter shoots a stream of plasma that can be used to cut a variety of substances. It’s the heat of the plasma combined with the tiny pinprick size that slices through the material.
What Is Plasma?
As mentioned, plasma is a state of matter consisting of ionized gas. Due to the structure of gas and the fact that plasma starts life as a normal gas, it appears to most outside sources as just another type of gas. This is why it took scientists so long to discover that plasma is something else entirely. It conducts electricity with such strength that it can burn and cut.
It’s not complicated to cause plasma, in point of fact it’s a fairly well known scientific principle. All you need to do is energize a gas enough for the electrons on the outer layer to break away. Of course, making that happen is a bit more difficult than just explaining it. Thermal energy is the normal choice, but the technology to create plasma reliably just wasn’t there. These days, it is!
The Principle Function of a Plasma Torch
Like any other kind of torch, a plasma torch directs a tight stream of plasma that melts the material you’re cutting. There are a variety of designs that create the plasma, though it’s usually a form of electrical energy. Direct current is the one most often used. It produces a flame that’s far more stable, as well as being easy on energy consumption. Since the flame is more stable with less heat, there’s not as much wear and tear on the device.
The nozzle within the torch keeps a steady stream of gas flowing. It’s essentially a cathode. The anode, another part that helps light up the torch, may be interior or exterior. When an electric arc begins hopping between the two electrodes, this heats the gas flowing from the nozzle. Since the gas is moving at such a high speed, it ensures that you won’t get a plasma build up in the nozzle. If you do, you should stop using it immediately.
The best plasma cutter devies generally have water-cooling devices. You’ll find several different variants on the basic design. You’ll not only see conventional torches, but there are also dual torches. This is a torch where a second stream of gas is used to surround the plasma stream. Since this cuts the plasma off from the surrounding atmosphere, it allows for a cleaner cut. The higher end torches replace this second stream of gas with water, instead. This allows it to cool the cutting area immediately after cutting. Naturally, there are specialty designs that allow for high-precision cutting.
You can easily find a number of advantages to a plasma cutter:
- Cutting Speed – Due to the use of plasma rather than fire, robotic plasma cutters can cut through material around 5X quicker than traditional torches. Some torches have been measured at 500 inches per minute.
- Wider Variety of Use – Since plasma cutters allow for such quick, precise cuts you can use them in more situations than you could use a traditional fire torch. The fact that they use nitrogen allows them to cut through the toughest metals.
- Ease of Use – You shouldn’t need any special training to use a plasma cutter. They’re used in the same way as traditional torches, with a few differences due to cutting fuel.
- Safety – While too much build up in your cutting torch can always cause problems, nitrogen isn’t known for being flammable on its own. This means there aren’t as many safety hazards as there would be with other torches.
- Economical – In spite of its science fiction sounding specs, a plasma cutter is actually cheaper than water-jet or laser cutters.
- Doesn’t Heat Up Surrounding Area – One of the biggest problems with cutting torches is how they heat up the material around the cut. Plasma torches don’t expend heat the same way as a traditional torch. So you won’t have to worry about warping damage.