The Plasma cutting is a process for separating materials using a plasma jet at high temperatures. A gas is heated to a very high temperature and ionized to create the plasma.

The plasma flame has a temperature of several thousand degrees Celsius. They are able to break through most materials. The prerequisite for being able to cut with plasma is that the material is electrically conductive. Special cutting gases are used to generate the plasma and cool the kerf at the same time. Eckert Cutting would like to show you which cutting gases are suitable for plasma cutting. Our experts explain what you need to look out for when using cutting gases.

Which cutting gases are suitable for plasma cutting?

There are a number of cutting gases that are suitable for plasma cutting. Most commonly used are these gases:

• Argon
• Hydrogen
• Nitrogen
• Oxygen

All gases have their own advantages and disadvantages. Argon, an inert gas, produces a stable plasma flame and is suitable for most applications.

Hydrogen is flammable and requires special precautions, but has a higher thermal conductivity than argon. However, this enables a higher cutting speed.

Nitrogen is a rather inexpensive gas that is well suited to cutting thick materials. Oxygen is an oxidizing gas that offers a high cutting speed. However, there is also a higher risk of oxidation and corrosion.

How cutting gases process the material

When the gas is passed through a high-temperature plasma flame, cutting gases are produced during plasma cutting. The cutting gas is ionized in the flame and split into free electrons and positive ions. To bring the cutting gas up to temperature. It is heated in the plasma flame using a high-frequency alternating current. Light and heat are generated. At the same time, kinetic energy is released.

The electrons collide with the atoms and molecules of the gas, resulting in additional ions and electrons. The temperature, speed and quality of the plasma jet can be changed by increasing the voltage.

Which cutting gas is suitable for which material?

When selecting a suitable cutting gas, it is important to consider the material properties and its thickness. Oxygen (O2) and nitrogen (N2) are normally used in the production of steel and other metallic materials.

Argon (Ar) is often used to cut aluminum and other non-metallic materials. It is an inert gas that prevents the material being cut from oxidizing.

In contrast to cutting gases, however, argon is not well suited to cutting thicker sheets. However, it is the better choice for heat-sensitive materials such as plastic.

Hydrogen (H2) is mainly used in plasma cutting for processing aluminum and stainless steel. It offers advantages such as better cutting quality and a higher cutting speed.

Oxygen (O2) is an extremely reactive gas, which is why it is ideal for cutting steel. The oxygen gas reacts with the steel and forms an oxide layer, which makes it easier to process the material.

In addition, the oxygen gas increases the cutting speed and enables thin sheets to be cut more precisely and cleanly.

In contrast, nitrogen (N2) is used as a "shielding gas" in plasma cutting. This is possible because nitrogen is an inert gas. It prevents the oxygen in the ambient air from reacting with the material being cut and oxidizing. Thicker sheets are mainly cut with nitrogen. It promises a higher cutting quality on this basis.

When cutting gas by-products?

Normally, no harmful gas by-products are created during plasma cutting. However, the use of nitrogen and oxygen can lead to a small amount of nitrogen oxides (NOx). These can be harmful to health at higher concentrations. In order to avoid these by-products of cutting gases, it is important to maintain the cutting system properly. All cutting parameters must be set correctly. It is advisable to ventilate the workplace environment sufficiently.

If necessary, professional extraction systems should be used. This not only extracts unwanted gases from the cutting zone, but also immediately purifies the ambient air from them.

Plasma cutting without gas - is that possible?

Plasma cutting cannot be carried out without cutting gases if a high cutting quality is expected. The cutting gases maintain the plasma discharge and protect the material to be cut at the same time. Thus, the choice of the right cutting gas is crucial for the quality of the cutting process and the result of the cut.

But it is possible to cut without gas. If you reduce the plasma strength at the nozzle and increase the distance to the material, it can be implemented. However, as it has a low cutting performance and poor cutting quality, this method is rarely used.

To achieve an optimum cutting result, the cutting gas should be adapted to the material and thickness of the material. The formation of gas by-products can be reduced by setting the cutting parameters correctly. Regular maintenance of the cutting system is also required.

We are happy to advise you!

If you have any further questions about cutting gases for plasma cutting, please do not hesitate to contact us. Our experts will be happy to advise you on the best cutting gas for your requirements.

Eckert Cutting offers a large portfolio of CNC plasma cutting machines of the very highest quality. We will be happy to help you with your further request and look forward to hearing from you!