Why Do We Use Nitrogen Gas During Laser Cutting?

Why do we use nitrogen gas during laser cutting?

What is laser cutting?

Laser cutting is a widely used heat treatment process in industrial manufacturing. Laser cutting machines can quickly carve and cut metal plates, achieving high-quality surface smoothness even when processing particularly complex shapes.

This production process is widely used in various industries such as automobiles, aerospace, electronics, and healthcare, and can be used to cut various materials such as metals, plastics, ceramics, wood, fabrics, and paper.

How does a laser cutting machine work?

The working principle of a laser cutting machine is to guide a high-power laser beam through optical devices and project it onto the material to be cut. The laser beam is focused through a lens and projected onto the material to rapidly increase the temperature of the local material and cause melting or vaporization. Then, using coaxial airflow to blow away the molten material, the material is removed and a cutting effect is formed. Air flow also helps to cool materials, preventing them from warping or twisting. The laser cutting machine is controlled by a computer numerical control (CNC) system to ensure the accuracy and precision of the cutting process.

What is the auxiliary gas in laser cutting?

Auxiliary gases are used in laser cutting to improve the quality and efficiency of the cutting process. Auxiliary gas can help blow away molten materials and prevent them from solidifying again on the surface of the material. In addition, it also helps to cool the material and prevent it from twisting or deforming. Nitrogen, oxygen, and compressed air are the most commonly used auxiliary gases in laser cutting.

1. Using nitrogen gas in laser cutting

Nitrogen gas is the most widely used auxiliary gas in laser cutting, thanks to its reactive inertness. It is used to ensure high-quality performance of the laser, especially when high-quality cutting is required. Nitrogen can eliminate oxygen in the air, thereby preventing oxygen from reacting with hot metals, achieving ideal and bright cuts without affecting the color of the material (depending on the purity of the nitrogen used). Nitrogen is an inert gas that allows lasers to operate in an oxygen free environment, preventing edge oxidation. Nitrogen also plays an important role in reducing costs, accelerating cutting speed, improving productivity, improving control performance, and achieving efficient machining. Optional "plug and play" solution for on-demand nitrogen supply.

2. Using oxygen in laser cutting

For materials that are difficult to process by other methods, laser cutting will use oxygen as an auxiliary gas. Oxygen is a highly reactive gas that can double the power of a laser beam and cause an exothermic reaction, thereby cutting thicker materials. Oxygen will react with the material being cut, promoting material melting and vaporization through chemical reactions. Depending on the material, oxygen can also be used to improve cutting speed and reduce cutting costs. However, oxygen may cause oxidation, forming a carbonized layer on the cut edge, which can result in poor surface quality of the product. The oxidized surface can also affect the adhesion of the coating or paint surface. In addition, oxygen reacts strongly and cannot obtain very thin slices.

3. Use compressed air in laser cutting

Compressed air can also be used as an auxiliary gas in laser cutting, and can also improve the speed and economic benefits of laser cutting. However, due to the 21% oxygen content in the air, using compressed air as an auxiliary gas for laser cutting cannot produce parts with clean cuts (usually, these parts need to be deburred before entering the next process, which requires additional manual labor). This type of cut quality is sufficient for parts that need to be painted or welded later, as the color of the cut edges is not important.

What is the general purity of auxiliary gas?

The purity of the auxiliary gas depends on the customer's requirements for the final product, but the following points must be considered:

If air is used, we cannot change its purity, so it will contain 78% nitrogen and 21% oxygen.

If oxygen is used, the purity is usually higher than 99.5%.

If nitrogen is used, the purity will depend on the material to be cut, whether the material needs further processing, and the importance of the cut edge color.

High pressure compressors and booster machines used for laser cutting typically rely on compressed air or compressed gas to achieve various functions, including improving the performance of the laser itself. High pressure compressors and boosters can provide necessary compressed air or auxiliary gas (such as nitrogen) for laser cutting processes. They can ensure a stable and reliable power source for the laser and promote stable and accurate cutting. High pressure compressors are used to compress gases such as nitrogen or oxygen, playing an auxiliary role in laser cutting. Applying pressure to the auxiliary gas can enhance the cutting ability of the laser and help deliver high-pressure gas to the cutting head to achieve ideal performance.

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