One of the important characteristics of gas laser is that the working substance of laser is mixed gas or single pure gas. Because the purity of the component gas in the laser mixture directly affects the performance of the laser, especially the presence of impurities such as oxygen, water and hydrocarbons in the gas will lead to the loss of laser output power on the mirror (surface) and the electrode, and will also cause the instability of laser emission. Therefore, there is a special requirement for the purity of laser mixture components, and the cylinder packaging the mixture must also be dried before filling to prevent contamination of the mixture. If the helium (He) neon (Ne) laser as the first generation of gas laser, carbon dioxide laser is the second generation of gas laser, in the semiconductor manufacturing field will be used in a large number of Kryptonfluoride (KrF) laser, can be called the third generation of laser.

Mixture of laser light is used to produce the laser laser generator gas, the gas quality requirement is high, the laser mixture preparation high accuracy, high purity carbon dioxide purity of 99.999%, the purity of high purity nitrogen 99.999%, the purity of high purity helium requires 99.999%, carbon dioxide is the laser, helium gas is cooled laser, nitrogen gas is balance, the moisture in the gas, oxygen, organic gas impurities of lens injury especially in laser machine, can quickly reduce the service life of the lens. So the laser machine has a very high requirement for the mass of these gases.

The auxiliary gas of laser cutting is mainly dry air, high-purity nitrogen or industrial oxygen. When cutting stainless steel plate or aluminum plate, high-purity nitrogen is generally used as the auxiliary gas, and the general pressure requirement is relatively high. When cutting carbon steel, oxygen is generally used to cool the cutting edge and accelerate the combustion of carbon steel to increase the cutting speed. Of course, when the cylinder thickness is thin and the cutting quality requirements are not high, dry air can be used to replace high purity auxiliary gas such as nitrogen. The general quality requirement of cutting auxiliary gas is not high, the key is that the price is cheap and the pressure is suitable.