Laser cutting machines need to use different auxiliary gases to cut various materials during processing

Laser cutting machines need to use different auxiliary gases to cut various materials during processing. The pressure and flow rate of the auxiliary gas are related to the thickness of the cutting material. This article will introduce in detail the auxiliary gases commonly used in laser cutting machines, their functions and costs.

Selection of auxiliary gas

Different auxiliary gases can be selected according to the type and thickness of the cutting material. For carbon steel, oxygen is recommended; for stainless steel, nitrogen is recommended; for easily oxidized materials such as aluminum and aluminum alloys, argon can be considered. When selecting auxiliary gas, cost and cutting effect must also be considered. 

Common auxiliary gases

The auxiliary gases commonly used in laser cutting machines are air, oxygen, and nitrogen. Their main functions are to help combustion, blow off the cut melt, and prevent oxidation.

1. Air

Air is the lowest-cost auxiliary gas, and most customers will choose to use it. Air contains about 20% oxygen, but the cutting efficiency is far less than pure oxygen, and is similar to nitrogen. When using air as an auxiliary gas, a trace oxide film will appear on the cutting surface, and the cut end face will turn yellow. Although the oxide film may affect the performance of the material, for some applications, this is not a critical issue.

2. Oxygen

Oxygen is ideal for cutting carbon steel. It can help burn and blow away the cut melt, increasing the cutting speed. The purity of oxygen is generally required to be above 99.5% and the pressure is 0.3-0.8 MPa. When using oxygen as an auxiliary gas, the cutting speed is faster and the cost is relatively cheap.

3. Nitrogen

When cutting stainless steel, nitrogen should be used as an auxiliary gas. Nitrogen can prevent oxidation reactions and blow away molten materials, maintaining the smoothness of the cut surface. Nitrogen purity requirements are high (especially for cutting stainless steel with a thickness of more than 8mm, the purity must reach 99.999%), and the pressure requirements are also high, generally 1Mpa. When cutting stainless steel with a thickness of more than 12mm or up to 25mm, the pressure must reach 2MPa or higher. When using nitrogen as an auxiliary gas, the cut end face is white and the cost is high.

Summary

Fiber laser cutting machines need to use appropriate auxiliary gases during processing to ensure cutting quality and efficiency. Air, oxygen, nitrogen and argon are commonly used auxiliary gases. Air has low cost, but the cutting effect is relatively poor. Oxygen is suitable for carbon steel cutting, with faster cutting speed and lower cost. Nitrogen is suitable for stainless steel cutting, which can maintain the smoothness of the cutting surface, but the cost is higher. Argon is suitable for inert gas cutting to prevent oxidation and melt cutting, but the cost is higher. When selecting auxiliary gas, comprehensive consideration should be given to the type and thickness of the cutting material as well as the cost and cutting effect.