What is Plasma?
Plasma in a nutshell is a ‘charged gas’ consisting of ions and free electrons. It is one of the distinct states of matter in addition to Solids, Liquids and Gases. Plasma is electrically conductive and highly reactive to magnetic fields.
As exotic as it sounds, plasma is commonly found around us in everything from neon signs to lightening and the sun.
So what can we do with Plasma? Continue below to see how plasma cutters use the 4th state of matter to cut through almost any conductive metal.
Plasma Cutter Overview
A plasma cutter is a useful tool that can be used to cut a number of different metals. Cutting metal with precision and clean edges isn’t a trivial task. A good plasma cutter can slice through materials of various thicknesses with ease.
They’re used in a variety of different construction and manufacturing industries. For the home welder, investing in a plasma cutter will speed up your cutting process as well as increase your accuracy when making cuts.
How Does a Plasma Cutter Work?
A plasma cutter utilizes plasma to cut into metal. Like a welder, it uses gas such as oxygen, argon, and nitrogen to create an electric arc. The gas flows through a nozzle that is heated, transforming it into plasma. Most units for home use will require a source of dry compressed air typically supplied by an air compressor.
This heated plasma can reach upwards of 40,000 degrees Fahrenheit and can easily cut through copper, brass, aluminum, and even steel with very little resistance. It creates clear, defined lines that are cleanly cut, saving time and that are easier to grind or finish.
Types of Plasma Cutters
Handheld Plasma Cutters
Manual or conventional plasma cutters are usually handheld devices that require an air supply or bottled gas. They’re fairly compact and very versatile but limited when cutting very thick materials. The conventional plasma cutter excels at making precision and rapid cuts. They require no pre-heat time and work well when cutting stacked materials.
The vast majority of plasma cutting machines on the market for consumers will be handheld models. Low cost CNC tables do exist as well for those needing automation. They can provide computer controlled cutting for the average home user.
Mechanized Plasma Cutters
Mechanized plasma cutters are larger and are used for bigger projects or for repetitive projects. These devices have more features and need a large cutting table to do their job. They’re not as portable because they need a large power supply. They’re best used for cutting thick, large pieces of metal. Many of these plasma cutters are CNC or computer numerically controlled tools that can be fully automated. Factories can use CNC plasma cutters to produce thousands of identical components quickly and efficiently.
These plasma cutters produce very sharp cuts that are needed for high quality projects. They have additional components that help control the accuracy of the cut and often use gas that is a mixture of multiple components in order to produce optimum results.
Parts of a Plasma Cutter
A plasma cutter has three different parts to it. The first is the power supply. It converts AC voltage into DC voltage that ranges from 200 to 400 VDC. The voltage sustains the plasma arc and regulates the output based on the thickness of the metal.
The arc starting console is the actual circuit that creates an AC voltage of around 5,000 VAC. This is what creates the spark inside the plasma torch, which then creates the plasma arc.
The plasma torch is the third part of the plasma cutter. It aligns the plasma and allows you to control where it interacts with the metal. The torch contains an electrode and a swirl ring to generate the plasma arc, which then exists the torch at the nozzle. The torch may also use an extra shielding cap to help improve the overall quality of the cut.
When looking at maintenance, there are typically four parts of your plasma cutter than will need replaced over time: the swirl ring, the electrode, the shield cap, and the nozzle (sometimes referred to as the retaining cap).
Plasma Cutters vs Oxy-Fuel Cutters (Cutting Torch)
While similar to a plasma cutter, an oxy-fuel cutter is a different type of cutting tool. It heats metal to the current ignition temperature by using a flame produced by a mixture of a fuel gas and oxygen. A jet of oxygen then hits the metal, causing a chemical reaction that forms slag and blasts it off the project. Oxy-fuel cutters can be a good option for some tasks and, in some cases, do work better than plasma cutters. Both tools have their uses, and you may need to invest in both to work as effectively as possible.
However, for many basic metal-cutting tasks, a plasma cutter is often the better option for a few different reasons. If you’re cutting through metal that is no more than 25 millimeters thick, a plasma cutter is going to be able to cut through it much more quickly than an oxy-fuel cutter. This means you can reduce the amount of time you spend cutting metal and more quickly move on to the next portion of your project. Your finished cut will also be ‘cleaner’ and more accurate compared to one made by a cutting torch.
Despite the extreme temperatures they operate at, plasma cutters also tend to be safer than oxy-fuel cutters because there is no open flame, nor do you need to use any highly flammable gas.
That being said, there are dangers when operating them. Since there tends to be more voltage at the torch head, they can present a more significant shock than say a welding machine. Always follow the manufacturers safety procedures and recommendations when operating a plasma cutter.
Buying a Plasma Cutter
If you’re ready to invest in a plasma cutter, there are a few things to keep in mind. First, you want to make certain that your work area has the right electrical setup. Most plasma cutters on the market for home use can these days are dual voltage (220v/120v) but a few are 220v only so be sure to check or be ready to hire an electrician. Note that if you are operating a plasma cutter off a 120v outlet, it won’t have as much power, so it won’t be able to cut as quickly or through really heavy gauge metal.
Next, consider the projects you’ll be working on and how thick the metal will be. Most plasma cutters can cut metal that’s a half inch thick or less. If you’ll be using thicker materials, be certain the cutter you buy can handle them and plan on using it with 220v.
Look for units with high frequency non-touch technology as well. Compared with traditional ‘touch start’, the non-touch unit doesn’t need to physically touch your material to create an arc. The end result is high precision cuts as well as less damage to the torch.
Finally, if you do purchase a plasma cutter, remember to purchase consumables as well. At the temperatures the cutter generates, even occasional use will require additional nozzles and electrodes.
