Plasma cutting: A complete guide

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Plasma cutting: A complete guide

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Plasma cutting is by far the most used process today in the industry to cut through metals. The other options are oxyfuel, laser cutting, and waterjet cutting.

The plasma cutting market is expected to grow 11.23% during the period 2022-2027. The reason behind this growth is the enhanced accuracy in cutting operations, the growing demand from conventional end-users (like hobbyists), and the high growth potential in emerging economies, mainly in Asia.

So, plasma cutting is here to stay. Then, it is worth getting to know everything about it.

What is plasma cutting

Plasma cutting is the name given to an industrial process that uses a plasma torch to cut through electrical conductive metals and other materials. The system used a high-frequency generator to ionize a high-temperature gas and create a plasma arc that melts the metal and blows away the molten material with a high-speed jet of ionized gas. The plasma arc cuts the workpiece by first melting it, and then blowing away the molten metal.

The working principle is that a beam of superheated (at temperatures above 20,000°C), electrically ionized gas is applied at high speed through a nozzle, to a conductive metallic workpiece, forming an arc. As electricity travels, it delivers sufficient heat to melt through the workpiece. The compressed gas blows the hot molten metal away, cutting through the workpiece.

Compressed air is usually used for plasma cutting, but some inert gases like argon, argon/hydrogen, or nitrogen, can be used also, especially when a high definition is required.

The process can be used for cutting various types of materials, including steel, aluminum, brass, copper, nickel, titanium, and other conductive metals and alloys. It can be used on both ferrous and non-ferrous materials. Additionally, plasma cutting can be used to cut materials of varying thicknesses, making it a versatile cutting method.

Plasma cutting is commonly used in industrial applications, such as metal fabrication, automotive repair, and construction. It is a highly precise method of cutting, allowing for clean, accurate cuts with minimal material waste.

Due to its low-cost, possibility to automate, accuracy, and more, it has turned out to be the most efficient and effective way to cut metals.

What is Plasma?

Plasma is a superheated matter that forms an ionized gas.

It is often called “the fourth state of matter,” along with solid, liquid, and gas. In the same way, a liquid will boil when energy (heat) is added, a gas will become plasma by heating it or subjecting it to a strong electromagnetic field.

The stars and even our own sun are made out of plasma. As a matter of fact, it is calculated that 99% of the universe is composed of plasma.

The history of plasma cutting

Plasma cutting has roots in the early 1900s when electric arc welding was first developed. The first plasma arc cutting system was invented in the 1950s by engineers at the Linde Air Products Company in New York. Plasma cutting was first demonstrated by Dr. Robert Gage at Union Carbide in 1957 as a substitute for oxyfuel.

In the years that followed, plasma cutting technology continued to evolve and improve. In the 1960s, researchers developed a method for using compressed air instead of nitrogen as plasma gas, which made the process more economical and easier to use. At this time, plasma cutting equipment was large, slow, and expensive. Usually was dedicated to repeating cutting patterns in a mass production mode.

In the 1970s, computer-controlled plasma cutting machines were developed, which allowed for more precise and efficient cutting, giving them greater flexibility to cut diverse shapes on demand, based on a set of instructions that were introduced into the machine’s numerical control.

Today, plasma cutting is widely used in various industries, including automotive, aerospace, construction, and metal fabrication. The process has become an essential tool for cutting metal and other materials quickly, accurately, and efficiently, and it continues to be refined with advances in technology and materials.

Steps for plasma cutting

Plasma cutting works by using a plasma torch to create a high-temperature plasma arc that can melt through metal and other materials. The process involves the following five steps:

  1. The plasma torch is connected to a power supply, which provides the electrical energy needed to create the plasma arc
  2. The torch contains a nozzle (or a cartridge), which focuses a stream of ionized gas (usually compressed air or nitrogen) into a narrow jet
  3. The power supply generates a high-voltage, high-frequency electrical current that passes through the gas in the torch. This causes the gas to become ionized, creating a plasma arc
  4. The plasma arc is directed onto the surface of the material to be cut. The intense heat of the plasma melts through the metal, creating a narrow cut
  5. As the plasma arc cuts through the material, the ionized gas flowing through the torch blows away the molten metal, leaving a clean, precise cut.

The process can be automated using computer-controlled machines that move the plasma torch along a predetermined path to create complex shapes and designs.

The most reliable cutting process

Plasma cutting has never been easier

Hypertherm is the most reliable, easy to use, and durable plasma cutting equipment out there.

What are the advantages of plasma cutting?

Plasma cutting offers several advantages over other cutting methods. The following are some of the reasons why you should get your plasma cutting power source as soon as possible.

Versatility: Plasma cutting can be used to cut a wide range of materials, including steel, aluminum, copper, and other conductive metals.

Speed: It is a fast-cutting method, allowing for quick and efficient cutting of large or small pieces.

Precision: It is a precise cutting method, allowing for clean, accurate cuts with minimal material waste.

Cost-effective: It can be more cost-effective than other cutting methods, especially when cutting thicker materials.

Portability: The machines can be relatively lightweight and portable, making them ideal for on-site cutting or fieldwork.

Automation: The machines can be automated with computer-controlled systems, allowing for precise and repeatable cuts, even on complex shapes.

Reduced Heat-Affected Zone: It produces a narrow kerf and a small heat-affected zone, minimizing distortion and warping of the cut material.

Nevertheless, we need to disclose as well the disadvantages of plasma cutting. So, let’s talk about that now.

What are the disadvantages of plasma cutting?

While plasma cutting offers many advantages, there are also some disadvantages to the process, including the following ones.

Limited thickness: Plasma cutting is generally not as effective on materials over a certain thickness. Thicker materials require more power and can result in slower cutting speeds, decreased accuracy, and increased consumable wear.

Clean-up: It can generate significant amounts of smoke, fumes, and debris, which can be hazardous to health and require additional clean-up time.

Noise: It can be very loud, which can cause hearing damage and be a source of noise pollution.

Consumables: It requires consumables, such as electrodes, nozzles, or single cartridges, which can wear out and need to be replaced periodically. This can add to the cost of the cutting process.

Safety hazards: It involves high temperatures and electrical currents, which can pose a risk of burns, electrocution, and fire if proper safety procedures are not followed.

Initial cost: The equipment can be more expensive than other cutting methods, like oxyfuel, which can make it less cost-effective for smaller-scale operations.

Now, after understanding the pros and cons of plasma cutting, let’s consider its main uses.

What are the main uses of plasma cutting?

Since its initial development, plasma cutting has evolved and improved. Nowadays is widely used in many industries. The main uses of plasma cutting are the following:

Industrial metal fabrication: Plasma cutting is commonly used in industrial metal fabrication, where it is used to cut through large sheets of metal quickly and accurately. It is used to cut through a variety of metals, including steel, aluminum, and copper.

Automotive repair and restoration: It is also commonly used in automotive repair and restoration. It is used to cut through rusted or damaged metal parts, such as body panels and exhaust systems, allowing for repairs or replacement.

HVAC (Heating, Ventilation, and Air Conditioning) installation and repair: It is used in the installation and repair of HVAC systems. It is used to cut through ductwork and other components made of sheet metal.

Artistic metalwork: It is also used in the creation of artistic metalwork. It allows artists to create intricate designs and shapes in metal that would be difficult or impossible to achieve with traditional cutting methods.

Demolition and salvage: It is used in demolition and salvage operations to cut through metal structures, such as ships, bridges, and buildings. It allows for the quick and efficient removal of metal components.

Equipment required for plasma cutting

In comparison with other industrial processes, plasma cutting is relatively simple to apply, because it requires just a few items. Let’s describe them.

Power source: This is the primary piece of equipment used for plasma cutting. It is a machine that generates a high-speed plasma stream and directs it toward the metal being cut.

Air compressor: It is required to supply compressed air to the plasma cutter. The power source uses compressed air to create the plasma stream.

Gas supply: In addition to compressed air, some plasma cutting machines require a separate gas supply, such as oxygen, nitrogen, or argon. The gas is used to enhance the plasma cutting process and improve the quality of the cut.

Torch: The torch is the part of the plasma cutting equipment that actually comes into contact with the metal being cut. It includes the electrode, nozzle, swirl ring, or a single cartridge.

Consumables: The consumables are the parts of the torch that wear out over time and need to be replaced periodically. This includes the electrode, nozzle, and swirl ring, or the single cartridge, in the case of the Hypertherm SYNC product line.

Protective gear: Plasma cutting produces intense heat and light, as well as sparks and fumes. As a result, protective gear such as gloves, eye protection, and a respirator may be required.

Workpiece support: The workpiece being cut needs to be securely supported to prevent it from moving during the cutting process. This may involve using clamps or other types of fixtures to hold the metal in place.

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Safety guidelines when using plasma cutting equipment

Typically, there are 2 main risks associated with plasma cutting: Arc eye and being reached by hot sparks.

Arc eye is what they call the brightness that comes out of a welding or cutting electric arc. This can cause eye damage. For that reason, OSHA recommends a shade 8 when using an arc current lesser than 300 amperes. The recommended shade might vary according to the manufacturer, but in normal conditions, something between 7 to 9 is acceptable.

The hot sparks and hot metal from plasma cutting can cause burns in the operators. The use of leather gloves, aprons, and jackets is highly recommended. In some situations, these sparks can fly up to 5 feet (1.5 meters) and land on flammable objects, which could start a fire in no time. Having a fire extinguisher close is a must.

As well as the operator, the people around the area need to be safe from the risks of plasma cutting. It is recommended that all of them might wear at least gloves and goggles, to prevent them from any harm.

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Regardless of the specific reason you might need plasma cutting, we have a solution in store for you. We have decades of experience with plasma cutting and can recommend the right equipment for you, based on your production needs.

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Codinter Editorial Team

Codinter Editorial Team

The Codinter Editorial Team is composed of a diverse and multinational group of specialists, researchers, and writers, equipped with field experiences throughout decades of developing solutions with technology for industrial purposes.

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