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How Does a Plasma Cutter Work? 

 May 31, 2022

By  Chris

by Chris

May 31, 2022

How does a plasma cutter work?

Have you ever wondered how does a plasma cutter work? How does it cut steel, stainless steel and aluminum with ease? They cut through metals like a hot knife through butter, but how?

Undoubtedly, metals are part of our daily activities because we engage with cars, skyscrapers, bridges, and other construction projects. Do we ever wonder how these strong materials end up as these large components? 

A plasma cutter is one of the most popular ways of cutting metals; they are known for their versatility, cost-effectiveness, and efficiency. It has been around since World War II. Since then, it has played a vital role in shaping the world as we see it today.

In addition, plasma cutting has proven helpful across different industries, especially automotive repairs, scrap metal operations, art, and manufacturing. It works fast and provides accurate cuts for users. If you can look around more closely today, there's a high chance you'll find something made through plasma cutting.

Here, you'll learn what plasma is and how a plasma cutter works with its pros and cons.

What is Plasma?

Since elementary school, teachers never failed to tell us about the three states of matter: liquid, solid, and gas. But we're here to tell you that your teacher was wrong because there's a fourth one named Plasma.

Before you raise your brows, hear this.

Plasma is a state of matter that you can find everywhere because it constitutes about 99% of the universe. Now, you must be wondering how your kind teacher would have omitted that, well, things happen.

But there are also things around you made of plasma like the popular polar lights, high-temperature fires, and TVs that we're talking about. And it's very different from the blood component found in your body, also named Plasma.

Other devices like neon lights, plasma displays, and fluorescent lights rely on plasma. However, these use cool plasma, which is unsuitable for cutting metals. It is equally useful with other applications essential to human life.

The popular definition of plasma is that it is "an electrically ionized gas-like substance that is conductive in nature." The simple explanation is that plasma comes into existence when gas increases to an exceedingly high temperature. It is referred to as ionized gas because the high temperature causes the gas molecules to split while the atoms also break apart.

Normal atoms have neutrons and protons within the nucleus, with electrons surrounding the outer part of the nucleus. Plasma is quite different because the electrons are separate from the nucleus. The heat energy loosens the atom's electrons, making the electrons move around fast.

When these fast-moving electrons meet with other electrons, they produce massive energy. It is where its remarkable cutting power stems from. Plasma functions like gas because the atoms are not close but also like a liquid because of its ability to flow.

Interesting, right? Keep reading.

Plasma Ground Clamp

The working clamp will be positive.

So How Does A Plasma Cutter Work?

A plasma cutter is a thermal cutting technique. It only means that it employs heat to cut metal rather than a mechanical method. A plasma cutter utilizes compressed air or gases that flows through a small channel.

An electrode with a negative charge is usually in the middle of this channel. You create a circuit when you apply power on the negative electrode, and the tip of the plasma torch nozzle is touched to the material to be cut. It generates an arc between the electrically conductive metal and electrode due to the positive ground clamp on the workpiece.

Torch Tip

Here you can see the torch tip where plasma exits the torch. The torch will be negatively charged.

The spark begins to heat up when the inert gas goes through the channel till it reaches the fourth state of matter, Plasma. It creates a reaction that produces a stream of directed plasma of about 30,000 to 40,000F.

The metal then reduces to a molten metal which the gases blow off simultaneously. Some dross will still be left on the metal workpiece.

There are also plasma cutters that have a pilot arc that allow you to cut through the metal with out having to touch the workpiece. The pilot arc is started at the tip of the torch. This is great for cutting through expanded metals with out having to start the cutting process all over.

Types of Plasma Cutters

Before choosing a plasma cutter, you need to understand that there's a significant difference between the ones created for industrial use and those meant for domestic purposes. There are generally two types of plasma cutters, and they include:

● Automatic Cutters

● Manual Cutters

Automatic Plasma Cutters

Also known as mechanized plasma cutters, they are big units used to handle work on a larger scale. You can easily find automatic cutters in industrial production lines involved in large steel-cutting jobs. You can operate them with a computer and a cutting table. You will often find automatic cutters that are useful for welding and plasma cutting.

When dealing with automatic cutters, you must consider the plate size, plate thickness, the number of sheets you cut, and the space you have for the machine. It will help you make the right choice among the numerous brands and models in the market.

A typical example is a Computer Numerically Controlled (CNC) plasma cutter that runs on software. It has automated features that make its work stand out among others.

There are some entry level CNC plasma cutters out there for small business and DIY hobbyist. Plasma table kits start around $1600

However, for effective operation, you need to get someone who understands how to create and edit the CAD files imported by the CNC. It will help you prevent waste and put it in the correct unit to facilitate accuracy.

There are different types of oriented cutters: the 3D/3 axis, the 2D/2 axis, and the tube and section CNC cutters. A 3D/3 axis is a type of CNC machine that cuts a third axis that is not 90 degrees. It is the type majorly used for cutting holes. On the other hand, a 2D/2 axis is the most popular one that cuts metal edges by 90 degrees. A tube and section cutter work for processing tubes, pipes, and other long material segments.

Manual Cutters

Another name for the manual plasma cutter is handheld plasma cutters. These devices generate high-cutting power that works best for light jobs like trimming. They are ideal for repair shops, construction work, shipbuilding, car repairs, artwork, garages, and even home space.

A manual cutter can either be a conventional or a high-definition precision cutter. A conventional cutter uses air instead of gases to heat the metal. It has an amperage between 65 - 200 amps.

Plasma Amps Adjustment Controls

The plasma cutter I use has an amperage adjustment knob and an air adjustment. It also has a selector to choose an internal air compressor or auxiliary air supply.

However, a high-definition precision cutter uses several gases like a mixture of nitrogen, argon, and hydrogen. It creates the highest definition cuts with a plasma pilot arc that ranges between 130 to 800 amps.

Benefits of Plasma Cutting

This advanced method of cutting metals has enormous benefits that it offers users, and they include:

Versatility

Plasma cutting is a highly versatile method of cutting metals that works for different materials. Using an electric arc, it cuts through brass, titanium, alloys, aluminum, iron, steel, stainless steel, copper, and others. Even if you have any of these materials stacked together, a plasma cutter will run through them efficiently. Using OxyFuel cannot provide such exceptional results.

Precise Cuts

If you want to cut out odd shapes, curves, intersecting cuts, and different angles with precision, you can trust plasma cutting. Once you get an experienced operator with steady hands, you will get accurate cuts. You can guide it as accurately as when working with a pencil controlled by either a computerized system or a manual one.

Speedy Operation

Plasma cutting has an incredible cutting speed that supersedes all others in the market. It helps you save time and execute your work in one-fourth of the time you'll require with other tools. Its speedy operations prevent erroneous cuts, distortions, and the risks of metal abrasion.

In addition, it doesn't require preheating before use which helps in slashing the cutting time. The best part is that it still works effectively and provides clean cuts for all users. Also, the piercing speed is less than 2 seconds compared to OxyFuel, which requires that you first heat the machine. Since plasma arc cutting works without prior heating, it slices through metals quickly.

Lesser Costs

This method of cutting metals is cost-effective. You can cut through metals at a lesser time with minimal waste or errors. Also, there are fewer tendencies for users to have injuries with these types of cutters.

You can get a decent hobby cutter for an affordable price if you're dealing with lighter jobs. These torches are low maintenance, and plasma cutters offer excellent value for money. This benefit helps in reducing costs at the end of the user.

Cutting blades are expensive and wear out fast cutting stainless steel at a high frequency. Consumables for a plasma torch are cheap compared to saw consumables when you look at how long they last. 

Plasma Air Supply

The plasma cutter I use has an auxiliary connection for an air line.

Air and electricity are cheaper and safer than fuels.

Ease of Use

Do you hate hauling huge equipment all around? Nobody likes it either. Plasma cutters come in different variations that are portable and easy to carry around. Regardless of the location, you'll need it. There are various brands you can trust that produce high-quality and lightweight products. There are even some that only one person can handle effectively. However, it works best for light to medium thickness metals.

Safety

Plasma cutting is a technique that uses inert gases that are not very flammable. However, oxygen-based cutting comes with possible dangers of explosion or even ignition that can happen accidentally. In contrast, plasma cutting involves the conversion of gas into plasma as the torch is in use.

Disadvantages of Plasma Cutting

Despite the mouth-watering benefits of plasma cutting, it has its drawbacks. They include:

● Plasmas are limited because they cannot cut metals with much thickness. They only work for metals that are deep by 1 inch. In cases where you want to cut blocks or giant steel pillars, you must rely on standard melting methods.

● The best place to use plasma cutting is an open space with proper ventilation. It is because it produces fumes and lots of noise. However, it can cut in water which helps reduce the noise.

● Plasma cutters have a notorious history of producing bright flashes while you're cutting through metals. All employees and individuals within the radius of the plasma cutter need to wear protective gear, especially for their eyes.

● Although it is a cost-effective option, it uses electrodes which can be costly and challenging to source for, especially in cases where the machine gets damaged. Also, fabricating the plasma mix required can be a hassle if you don't have specialist equipment.

Safety Requirements

Plasma cutting is safer than most techniques of cutting metal. However, it still has potential hazards, especially at the beginning of the work. There's a possibility that a blowback can occur when the metal sprays upwards while the plasma arc pierces through it. In other cases, the sparks from plasma cutting can cause severe damage and burns on the face, hair, head and even the clothes.

Here are some safety requirements you must follow:

● Wear safety glasses with side shields. You can also combine it with a face shield or helmet for increased protection.

● Wear flame-resistant gloves and clothes to protect your body from sparks. Try out clothing materials made with leather, heavy denim, or wool to protect yourself.

● The plasma arc is usually extremely hot, so it can easily cut through your skin. Never hold material close to the cutting path to prevent possible burns.

● Ensure that there's no flammable liquid, gas, or vapor around you when cutting to prevent explosions.

● Always check if the plasma cutter is well-grounded and properly connected to avoid electrical shocks.

● When you cut metal, it releases fumes and gases that harm your health. Keep your head at the torch's side to avoid inhaling it, or use an air-supplied respirator.

● Store the cylinders that contain compressed gases properly. Also, change faulty hoses quickly to prevent them from seeping into the air.

Final Thoughts

Now you know what a plasma cutter is and its used in the cutting process. Although plasma cutters offer precise cuts, you still need to practice your cuts and ensure that your hands are steady. I like using guide to help my unsteady hands.

It's like buying a gun. Regardless of how great the gun is, it won't work well for you if you don't practice getting accurate shots. However, you have nothing to worry about because plasma cutters are easy to figure out once you follow all the steps.

Also, remember that CNC plasma cutters are different in their handling. You will have to replace the consumables regularly to provide clean cuts. You must use the right speed, power level, and suspension to gain excellent results.

You have everything you need to know about how a plasma cutter works. Explore our website for more details on shop projects, welding tips and welding gear.

About the author 

Chris

Average guy that likes to build things and teach others what I learn. Family comes first. Steel, Jeeps and off-roading are all fighting for second place.

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