Expert Guide to Plasma Cutting: Types, Processes and More

Table of Contents

Plasma cutting is a process used to cut metal and other conductive materials using a high-temperature, ionized gas known as plasma. The plasma jet can reach temperatures up to 40,000 degrees Fahrenheit – much hotter than the temperature of the Sun!

The process is typically used for cutting metal sheets, pipes, and other similar materials. It’s also used in industrial applications such as manufacturing, automotive repair, and construction. Plasma cutting is faster and more precise than traditional cutting methods, such as sawing or oxy-fuel cutting, and produces less waste and heat-affected zones. However, it only works on electrically conductive materials, and thus, it is not possible for plasma cutters to cut stone, paper, wood, glass, plastics, or other poor conductors of electricity. 

At SendCutSend, we prefer laser cutters for accuracy, speed, superior edge quality and the ability to cut a wider variety of materials.

What is Plasma?

Plasma is the lesser known fourth state of matter, after solid, liquid, and gas. It’s a high-energy ionized gas that consists of atoms that have been stripped of some or all their electrons, leaving a mix of positively charged ions and negatively charged electrons. It is created when you expose a gas to very high temperatures or when you pass electricity through it. 

Plasma can be found in many places in nature, such as in lightning bolts, stars, and flames. It is also used in industrial and medical applications, such as in plasma TVs, fluorescent lights, plasma cutters, and plasma torches.

Plasma is unique because it has properties that distinguish it from the other states of matter. For example, it can conduct electricity, respond to magnetic fields, and emit light. 

What is Plasma Cutting? 

The first plasma cutting systems used a simple torch design that used a high-velocity jet of ionized gas to melt and cut the metal. The early systems were limited in their cutting speed and accuracy, but they quickly became popular for their ability to cut through a wide range of metals and alloys.In the early 1970s, new plasma torch designs were developed that improved the cutting speed and accuracy of the process. They allowed for faster cutting speeds and improved precision. As computer technology advanced in the 1980s and 1990s, plasma cutting systems began to incorporate computer control systems that allowed for even greater precision and control. Today, plasma cutting is used in a wide range of industries.

Plasma Cutting vs. Laser Cutting: Pros and Cons

Both plasma cutting and laser cutting are effective methods of cutting through materials. However, there are some differences between the two techniques.

As mentioned before, plasma cutting is a thermal cutting process that uses a jet of high-velocity ionized gas to cut through materials. Laser cutting, however, uses a high-powered laser to cut through materials. Laser cutting is known for its precision, as it can make very fine cuts with clean edges and can also cut more quickly than plasma cutting. It’s often used for cutting thin materials (usually less than 1 inch), such as sheet metal, and can also be used to cut non-metal materials such as acrylic and wood.

Overall, both plasma cutting and laser cutting have their own advantages and disadvantages, and the choice between the two will depend on the specific needs of the project, as well as things like material, cut quality, material thickness, and price. Plasma cutters are typically more affordable than laser cutters.

AdvantagesDisadvantages
Plasma Cutting– Low maintenance compared to laser
– Can cut thicker materials, sometimes up close to 1.5 inches
– Lower costs
– Performs well on reflective materials
– Limited to only cut conductive materials
– Less accurate than laser
– Produces radiation during cutting (bright flashes can hurt eyes)
– Nozzle and electrode need replacing as consumables
Laser Cutting– High level of accuracy
– Can cut wider range of materials (not just metals)
– More energy efficient and faster option for cutting metal
– Does not perform very well cutting highly reflective materials
– In general, does not have enough power to cut greater thicknesses (close to 1 inch)

How Does a Plasma Cutter Work?

In general, the process of plasma cutting involves three main components: the power supply, the torch, and the workpiece. The power supply produces a high voltage electrical arc that is directed from the electrode in the torch, to the workpiece. The torch also contains a nozzle with a flow of gas that is forced around the electrode. When the electrical arc is directed through the gas, it ionizes the gas and creates a plasma jet of a very high temperature.

The plasma jet is then directed at the workpiece, which is usually grounded to complete the electrical circuit. The plasma jet melts the metal and blows away the molten metal with its high-velocity jet, leaving a clean cut in the material. The process can be used to cut through a variety of conductive materials, including steel, aluminum, copper, and brass. The cutting speed and quality can also be controlled by adjusting the power supply settings and the gas flow rate.

What are Some Types of Plasma Cutting?

There are several types of plasma cutting techniques used in the industry. Here are a few of them:

Conventional Plasma Cutting

This is the most common type of plasma cutting, where a plasma torch generates a plasma arc, which is used to melt the metal and blow away the molten material.

High-Definition Plasma Cutting

his type of plasma cutting is more precise and produces cleaner cuts with less bevel. It uses a smaller nozzle and a higher-powered plasma arc to achieve higher cutting speeds and better-quality cuts.

Water Injection Plasma Cutting

This technique uses a stream of water to cool the plasma arc and control the shape of the cutting arc, resulting in a narrower kerf and less heat distortion.

Underwater Plasma Cutting

This technique uses a water-filled chamber to perform the plasma cutting, which prevents the material from overheating and reduces the amount of smoke and noise generated.

Precision Plasma Cutting

This type of plasma cutting is used for cutting materials with high precision and accuracy. It uses a specialized software and hardware system to control the plasma arc and achieve the desired results.

Air Plasma Cutting

This technique uses compressed air as the plasma gas, instead of a mix of compressed air and other gasses, which makes it more cost-effective and easier to use, but may result in a lower-quality cut.

Mechanized Plasma Cutting

This technique uses computer-controlled machines to move the plasma torch, allowing for precise and repeatable cutting. This is commonly used in automated manufacturing processes, such as in the automotive or aerospace industries.

Dual Gas Plasma Cutting

This type of plasma cutting uses a combination of two gases, typically oxygen and nitrogen, to produce a higher energy plasma arc. This allows for faster cutting speeds and greater versatility in cutting different materials.

Types of Cutting Processes 

In addition to different techniques, there are also a few different cutting processes. 

High-Frequency Contact

A high frequency signal is used to initiate the plasma arc, which is then transferred to the workpiece using a contact torch. The contact torch is used to maintain the arc between the electrode and the workpiece, and to control the cutting speed and depth. High frequency contact plasma cutting is typically used for cutting materials up to 38mm thick, and is commonly used in industrial applications where high precision and clean cuts are required. This type of plasma cutting is also popular because it is relatively fast and can be used to cut a wide variety of metals and alloys, including stainless steel, aluminum, and copper.

Pilot Arc

In this process, a high voltage current is applied to the electrode, creating a small plasma arc or spark that jumps from the electrode to the workpiece. This small arc creates a pilot arc, which ionizes the gas and creates a plasma stream between the electrode and the workpiece. The pilot arc is then used to initiate the main cutting arc, which melts the metal and blows away the molten material with a high-velocity gas stream.

Spring-Loaded Plasma Torch Head

This process uses a spring-loaded mechanism to maintain a consistent distance between the torch head and the workpiece during the cutting process. This mechanism helps to ensure that the plasma arc is maintained at the correct distance from the workpiece, which is important for achieving a clean, precise cut.

What Kind of Gas do Plasma Cutters Use?

The choice of gas will depend on the specific material being cut, the thickness of the material, and the desired quality of the cut. Different gasses will produce different cutting speeds, edge quality, and heat-affected zones.

The choice of gas will depend on the specific material being cut, the thickness of the material, and the desired quality of the cut. Different gasses will produce different cutting speeds, edge quality, and heat-affected zones.

Compressed air

This is the most common gas used in plasma cutting, as it is readily available and cost-effective. Compressed air is used for cutting mild steel, stainless steel, and aluminum. A disadvantage is the potential to cause oxidation.

Oxygen

Oxygen is used in plasma cutting for cutting thicker materials, usually mild steel. Typically, those over 1 inch thick. It has a fast-cutting speed, but disadvantages are its cost, and the risk for oxidation if used on aluminum or stainless steel.

Nitrogen

Nitrogen is used for cutting stainless steel and aluminum. It produces a cleaner cut than compressed air and reduces the risk of oxidation on the cut edge. It is abundant and available in the atmosphere, making it relatively inexpensive. It also wears on parts less. However, it is usually used for cutting thinner workpieces. 

Argon/Hydrogen

Argon hydrogen mixture is the hottest burning plasma gas as it provides the maximum cutting capability. Usually used to cut thick stainless steel and aluminum, it provides a straight cut and a very smooth, polished surface. Disadvantages are its cost, and special safety precaution requirements. 

Common Materials Cut with Plasma Cutting:

Steel

Plasma cutting is commonly used to cut steel, including mild steel, stainless steel, and carbon steel. It is ideal for cutting thick and thin sheets of steel and can produce a clean and precise cut.

Aluminum

Plasma cutting can be used to cut aluminum, which is commonly used in the aerospace and automotive industries. However, aluminum is a highly conductive material, so the cutting process can be more challenging than cutting steel.

Copper

Plasma cutting can be used to cut copper, which is commonly used in electrical applications. However, copper is a highly conductive material and can be difficult to cut cleanly.

Brass

Plasma cutting can be used to cut brass, which is commonly used in decorative applications. However, brass is a highly conductive material and can be difficult to cut cleanly.

Cast iron

Plasma cutting can be used to cut cast iron, which is commonly used in the automotive and construction industries.

Titanium

Plasma cutting can be used to cut titanium, which is commonly used in the aerospace and medical industries. However, titanium is a highly reactive metal and requires specialized equipment and safety precautions.

Of the materials above, the most common are mild steel, stainless steel, and aluminum. The table below shows suggested gases to use for each material, and the benefits in relation to the material. 

Mild SteelStainless SteelAluminum
AirGood Cut Quality/EconomicalGood Cut Quality/EconomicalGood Cut Quality/Economical
OxygenExcellent Cut Quality and SpeedNot RecommendedNot Recommended 
NitrogenFair Cut Quality/Great Parts LifeGood Cut Quality/Great Parts LifeGood Cut Quality/Great Parts Life
Argon/HydrogenNot RecommendedGreat For Thicker than ½” Great For Thicker than ½”

Alternatives to Plasma Cutting and Laser Cutting

There are some alternatives to plasma cutting and laser cutting that are used in various manufacturing processes. Here are some examples:

Waterjet Cutting

This method uses a high-pressure stream of water mixed with abrasive particles to cut a variety of materials, including metals, plastics, and composites. Waterjet cutting is known for its high precision, versatility, and ability to cut thick materials.

Abrasive cutting

This method uses an abrasive wheel or blade to cut materials, such as metal, ceramics, and composites. It is often used for cutting and shaping hard materials.

Electrical Discharge Machining (EDM)

This method uses electrical discharges to erode materials, such as metals, to produce complex shapes with high precision.

Oxy-Fuel Cutting

Oxy-fuel cutting is mainly used to cut thick metals and has relatively low accuracy.

CNC Milling

This method uses a computer-controlled milling machine to cut through materials, typically by using a rotating cutting tool. CNC milling can be used to produce complex shapes and is particularly useful for cutting metals and plastics.

SendCutSend Helps You Choose the Best Cutting Method

At SendCutSend we offer laser cutting, waterjet cutting and CNC routing. When you upload your design to our website, we choose the best cutting method based on your design, material choice, and required finishes. If you’re new to laser and waterjet cutting you can use our material selection guide to help select the best material for your project. You can learn about the best choices for each material, as well as the cutting processes and post-cut operations that are available by referencing our material pages. If you need any assistance, reach out to our support team.

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We proudly use hardware by PEM

Flush Standoff, 4-40, .250" Zinc plus Clear Chromate

Aluminum: 5052, 6061, 7075 Steel: Mild, G30

SKUSO-440-8
Thread Size4-40 x .250″
Hole size in sheet (+0.003/-.0.000).168″
Minimum sheet thickness0.040″
Maximum sheet thickness.125″
Fastener materialSteel
Minimum distance hole C/L to edge0.230″
When determining the distance between two or more fasteners, you can calculate the distance by the formula, C/L to edge + 1/2 the diameter of the second mounting hole..345″
Recommended panel materialSteel/Aluminum
Coating typeZinc
Length.250″
Aluminum material ranges (5052, 6061, 7075)0.040″-0.125″
Steel material ranges (CRS, HRPO, HR)0.048″-0.119″

We proudly use hardware by PEM

Flush Standoff, 4-40, .250" Passivated

Stainless Steel: 304, 316

SKUSO4-440-8
Thread Size440
Hole size in sheet (+0.003/-.0.000).166″
Minimum sheet thickness0.04″
Maximum sheet thickness.125″
Fastener material400 Stainless Steel
Minimum distance hole C/L to edge0.230″
When determining the distance between two or more fasteners, you can calculate the distance by the formula, C/L to edge + 1/2 the diameter of the second mounting hole. Example shown with x2 of the same hardware..313″
Recommended panel materialStainless Steel
Coating typePassivated
Length.250″
304 Stainless Steel material ranges0.048″-0.125″
316 Stainless Steel material ranges0.060″-0.125″