In the metal processing industry, the laser cutting machine has been sought after and welcomed by users as a leader in the processing industry. To process the workpiece well, the auxiliary gas is an important part of the adjustment of the cutting process. The needs for the usage of supplementary gases vary depending on the kind of material and thickness of the cutting workpiece. The role of auxiliary gases and several common cutting auxiliary gases are described in detail below.
The Role of Auxiliary Gases
People new to laser cutting machines may have a question: Why do they need to rely on auxiliary gases for cutting? This is because using auxiliary gases can blow away the slag in the coaxial groove to prevent slag on the surface of the cutting workpiece, achieving a good cutting effect. The auxiliary gas can cool the processed workpiece and reduce the heat-affected zone. Third, blowing auxiliary gas can effectively prevent soot from entering the mirror holder and polluting the lens, protecting it and prolonging its service life. Fourthly, the auxiliary gas matching with the cutting material can react with the workpiece, play the role of combustion, and speed up the cutting speed. Using auxiliary gas for cutting is necessary, so how do you choose the right auxiliary gas?
Classification of Auxiliary Gases
Laser cutting machine auxiliary gases usually use four gases air, oxygen, nitrogen, and argon.
Air is a gas mixture containing nitrogen, oxygen and other gases. Its collection method is relatively simple. It is compressed by an air compressor into a storage tank and can be extracted after filtering, cooling and drying, requiring a low cost. The majority of its applications involve treating thin metal sheets. It uses air to help cut the workpiece and laser energy to melt the metal, blow away the molten material at high pressure, and create metal oxides through an oxidation reaction. It is mainly suitable for cutting carbon steel, aluminium, aluminum alloy, brass, electroplated steel plates and other metal materials.
Oxygen cutting can play the role of combustion. In the cutting process, oxygen reacts with heat and can greatly improve the cutting efficiency. The resulting oxide film will increase the beam spectral absorption index of the reflected material, thus making more efficient use of laser energy and increasing the speed of the laser cutting machine. Its cutting speed is mainly suitable for cutting thick plates, such as carbon steel, stainless steel, alloy metals, etc.
Nitrogen is chemically inactive and not easy to react with the oxidation of the workpiece being processed. It can effectively prevent film oxidation without cutting, and the cut surface will turn white. Using nitrogen for cutting requires high purity. Nitrogen can aid in cutting if the cutting surface is of a high calibre. Mainly suitable for cutting stainless steel, plated steel, brass, aluminum and other metal materials.
Argon is also an inert gas, chemically inactive, and not easy to oxidation reaction with the workpiece being processed. Compared with other auxiliary gases, the use of higher costs. It works best for cutting materials made of titanium alloy.
It should be mentioned that if you decide to use compressed air as auxiliary gas, you must make sure that it is free of water, oil, and dust to avoid contaminating the laser cutting machine’s optics, which could cause errors in the piping of the device or during the cutting operation. There are phenomena such as anti-seepage. Since argon and nitrogen are relatively expensive, the best auxiliary gas should be chosen after careful comparison.