When the laser cutting machine is processing, it often needs to use auxiliary gas to adjust the processing technology. The selection of auxiliary gas is very important for product cutting. The requirements for the use of auxiliary gas vary according to the material and thickness of the cutting workpiece. How to select the appropriate auxiliary gas? Common auxiliary gases include compressed air, oxygen, nitrogen and argon. How to choose? Let’s talk about it one by one.
1、 Compressed air
Air is a kind of mixed gas containing nitrogen, oxygen and other gases. The collection method is relatively simple. The air compressor is used to compress it into the gas storage tank, and it can be extracted after filtering, cooling and drying. The cost is small. The cutting efficiency is close to nitrogen, and the cutting surface is prone to yellowing.
It is mainly used in the processing of metal sheet. It melts the metal workpiece with the energy of laser, blows away the melt with high pressure, and uses air to assist in cutting the workpiece section, which will produce oxidation reaction and form metal oxide. It is mainly used for cutting metal materials such as carbon steel, aluminum, aluminum alloy, brass and electroplated steel plate.
Oxygen cutting can play a combustion supporting role. During the cutting process, the oxygen reaction heat can greatly improve the cutting efficiency. The generated oxide film can improve the beam spectral absorption index of the reflective material, so that the laser energy can be used more effectively and the cutting speed of the laser cutting machine can be accelerated. It is mainly applicable to thick plate cutting, such as carbon steel, stainless steel, alloy metal, etc.
The chemical property of nitrogen is not active, and it is not easy to react with the processed workpiece. It can effectively prevent the oxidation free cutting of the oxide film and the whitening of the incision surface. Nitrogen cutting requires high purity. Nitrogen can be used for auxiliary cutting if the quality of cutting surface is required to be high. It is mainly used for cutting stainless steel, galvanized steel plate, brass, aluminum and other metal materials.
Argon is also an inert gas, which is not active in chemical property and is not easy to react with the machined workpiece. Compared with other auxiliary gases, it has higher use cost and is mainly suitable for cutting titanium alloy materials.
It should be noted that if air is selected as the auxiliary gas, the compressed air should be free of water, oil and dust to prevent the optical lens of the stent cutting machine from being polluted, which may cause deviation of the laser cutting machine pipeline or impenetrability during the cutting process. The cost of nitrogen and argon is relatively high, so the most suitable auxiliary gas shall be selected for use after comprehensive comparison.