Construction steel, stainless steel, aluminum,... The CNC plasma cutter can be used to cut any electrically conductive material such as metals. This is made possible by the plasma cutter's plasma temperature of up to 30,000 °C. By comparison, a conventional welding machine works at around 3,000 °C. Even the surface of the sun (photosphere) has "just" around 5,500 °C.

How can a plasma cutter reach a temperature like this? More than five times hotter than the surface of the sun - but why doesn't the cutting head or the nozzle melt? Instead, it cuts metals with pinpoint accuracy and still has the right speed.

Eckert Cutting would like to take a closer look at this phenomenon with you. Find out why the plasma cutter can cut extremely high-quality results at temperatures in this range without a large heat-affected zone.

How can up to 30,000 °C be achieved?

No thermal cutting process such as autogenous flame cutting or laser cutting reaches temperatures like plasma cutting. Plasma technology uses an ionized gas that applies heat to the conductive material via an arc. This is usually oxygen from the circulating air. However, it can also be other gases such as argon or nitrogen, which are used for the plasma.

What is plasma?

Plasma is the fourth aggregate state of matter: solid <-> liquid <-> gaseous <-> plasma. To create plasma, atoms are strongly ionized and electrons are separated from their nuclei. Plasma can be influenced by electrical conductivity and magnetic fields. In nature, plasma often occurs in the form of lightning during storms.

By creating an electric arc between an electrode and the electrically conductive workpiece, a plasma cutter heats a gas to around 30,000 °C. The gas flowing through the arc is ionized into plasma. The exceptionally high temperatures generated by the energy of the electric arc cause the gas to enter the plasma state.

How much energy is required for the plasma cutter to reach the temperature?

The exact amount of energy required to heat a gas to 30,000 °C during plasma cutting depends on several factors, including:

• The type of gas used (such as air, argon, nitrogen)

• Gas pressure and flow

• The properties of the cutting material

• The design of the plasma cutter and its specifications

The amount of energy required to ionize an atom or molecule in a gas varies depending on the type of gas. In addition, the plasma requires continuous energy to remain in this state and not recombine.

What is recombination?

Recombination is the process in which a free electron collides with a positively charged ion. This creates a new neutral atom. The energy absorbed during ionization is released through this process in the form of light or heat.

It is necessary to multiply the specific ionization energy of the gas by the number of atoms or molecules to be ionized and add additional energy. This is the only way to maintain the conductive gas at a temperature of 30,000 °C. However, this would be a very simplified calculation, which could vary depending on the factors mentioned above.

Can energy be saved?

For a precise answer to the energy question, detailed information about the specific plasma cutting system and the operating conditions must be provided. To obtain an accurate estimate of the energy required, it would also be advisable to contact an expert such as Eckert Cutting. We can help you find the right amount of energy to set the temperature of the plasma cutter so that you save as much energy as possible on your project.

For orientation purposes, it is important to set the temperature of the plasma cutter according to the material properties, the material thickness, the cutting speed and the desired cutting quality. For all suitable materials, however, the plasma cutter must reach a temperature of at least 20,000 °C.

This is why the material is not damaged

Why is the material not damaged during plasma cutting, even though the cutting temperatures are far above the melting point of the materials? Although the plasma cutter works at temperatures of over 20,000 °C, there are several reasons why the material is not normally damaged:

Concentrated energy input: As the plasma is concentrated on a very small area, the energy is directed directly and precisely to the cutting area. The surrounding area remains comparatively cool.

Short exposure time: While the cutting head is moving, the material is only exposed to the plasma for a very short moment. This reduces the time the material is exposed to high temperatures and therefore also the risk of thermal damage.</p

Fast heat dissipation: Metals dissipate heat quickly. This means that the heat is quickly dissipated from the cutting area into the surrounding material. This reduces the likelihood of overheating.</p

Shielding gases: Shielding gases are often used in plasma cutting to help dissipate heat and protect the material being cut from oxidizing effects.

Blowing effect of the plasma: By blowing the cut material out of the joint, it is prevented from accumulating and damaging neighboring areas of the workpiece.

Let us advise you

Despite this, thermal distortions or changes in the microstructure near the cut area can occur during plasma cutting if unsuitable settings are used. To ensure high cutting quality without undesirable damage to the workpiece, it is crucial to use the correct parameters and techniques.

Therefore, let our experts advise you. Eckert Cutting is always ready to help you find the ideal plasma cutter temperature and technology for your requirements. If required, we can also offer your employees training in plasma cutting technology.

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