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How to Choose Suitable Auxiliary Gas for Laser Cutting Processing?

Have you encountered the subsequent confusion within the laser cutting process?

What kind of metal sheet matches what kind of gas?

How to choose auxiliary gas?

What aspects of cutting quality are going to be suffering from different gases?

Which auxiliary gas to settle on for different plates?

Disen Laser will take you to understand as following:


There are three kinds of auxiliary gases for laser cutting processing usually: compress air, nitrogen, and oxygen, and different auxiliary gases are wont to cut different metal materials.


1. Compressed Air 

Common in the field of non-metal laser cutting are solid laser cutting machines and gas laser cutting machines (carbon dioxide laser cutting machines). Non-metal laser cutting machines generally rely on laser power to drive the laser tube to emit light, and the light is transmitted to the laser through the refraction of several mirrors. The focusing lens installed on the laser head converges the light into a point, and this point can reach a very high temperature, so that the material is instantly sublimated into gas, which is sucked away by the exhaust fan, so as to achieve the purpose of cutting; general laser The main gas filled in the laser tube used by the cutting machine is carbon dioxide, so this laser tube becomes a carbon dioxide laser tube, and the laser cutting machine using this laser tube is called a carbon dioxide laser cutting machine.

For many years, when carbon dioxide lasers work on long shifts, they consume a lot of resources in terms of gas and energy, and require maintenance plans. In addition, the pulse parameters typically used in this application mean that sealed tube CO2 laser technology is not suitable. Overall, after years of extensive improvements, CO2 lasers are still behind other technologies in terms of reliability and maintenance issues. During maintenance, the beam quality of these lasers is still easy to change; the smallest spot size that can be achieved is also susceptible to long waves. Individually, the laser beam absorption characteristics of ceramics have allowed this technology to influence this market for a long time.

Due to the absorption characteristics of commonly used ceramics, carbon dioxide lasers have become the laser of choice. The energy of the pulsed carbon dioxide laser beam is absorbed on the ceramic surface, thereby causing local heating, melting and vaporization. Figure 2 shows a top view of a 0.0045 inch scribe line in alumina, indicating that during a relatively long pulse (approximately 75-300m, depending on the thickness), under the low energy edge of the Gaussian beam energy profile, because Heat-affected area caused by local melting.

Suitable for carbon dioxide laser cutting machines mainly include special parts requiring uniform cutting, stainless steel with a thickness of no more than three millimeters and non-metallic materials with a thickness of no more than 20 millimeters used in service industries such as advertising and decoration, and the other is the cutting contour Complicated but small amount of workpiece processing, used to save the cost and cycle of manufacturing molds. Wuhan Ruifeng Optoelectronics CO2 laser cutting machine is cost-effective, no less than the product quality of other brands. With years of laser research and development experience, the product technology is mature, the equipment and machine parts are selected from high-quality brands, and the product performance is safe and stable. Wuhan Ruifeng Optoelectronics Laser has always adhered to the attitude of "quality first, service second, price third" to provide customers with the best quality products.



2. Nitrogen(N2)

Nitrogen is a noble gas which may prevent oxidation of the cut end surface of the merchandise during cutting, and stop combustion (prone to occur when the sheet is thick). Nitrogen is often selected for products that need high-quality cutting surface and the surface don't get to be processed, like some decoration industries and special aerospace parts.



3. Oxygen(O2) 

Oxygen mainly plays a task in supporting combustion, which may increase the cutting speed and increase the cutting thickness of the materials. Oxygen is suitable for thick sheet cutting, high-speed laser cutting, and real-thin plate cutting. Oxygen is usually utilized in the cutting of some larger steel plates and thicker steel structures.


The auxiliary gas can't only blow away the slag in time when the laser cutting machine is running but also cool the workpiece and clean the lens. In daily operation, we should always choose the acceptable auxiliary gas consistent with the cutting material and thickness.



Different auxiliary gases are used to cut different materials. The thickness of the cutting material is different, the pressure of the auxiliary gas and the required flow rate are different.

The purity of oxygen used for cutting carbon steel is generally 99.5% or higher, and the main function is to support combustion and blow off the cut melt. What's more, the pressure and flow rate are different for each laser cutting machine manufacturer, which is inseparable from the size of the cutting nozzle and the thickness of the cutting material.

Generally, the pressure is required to be 0.3-0.8Mpa, and the cutting nozzle is generally 0.02-0.05Mpa. The flow rate is hard to say. For example, when cutting 22mm carbon steel, the flow rate of some manufacturers must reach 10M3/h (including the protective oxygen for double-layer cutting nozzles)

Nitrogen is used to cut stainless steel. The role is to prevent the oxidation reaction and blow off the melt. There are high requirements for the purity of nitrogen (especially stainless steel above 8mm, which generally requires a purity of 99.999%)

The pressure requirements are relatively large, generally 1Mpa or more, if you want to cut 12mm or more, or thicker to 25mm stainless steel, the pressure is higher, 2Mpa or more. The flow rate varies according to the model of the cutting nozzle, but they are all very large. For example, for cutting 12mm stainless steel, some manufacturers need 150m3/h while cutting 3mm, as long as the flow is below 50m3/h.

In terms of cost, the oxygen used for cutting carbon steel is relatively cheap, and the amount of nitrogen used for cutting non-carbon steel is large. The thicker the stainless steel requires a high amount of nitrogen and purity. The cost is high.