The auxiliary gas used by laser cutting machine to process different materials is different. The pressure and requirements of auxiliary gas are different for different cutting thickness. From the cost, cutting carbon steel with oxygen is relatively cheap, cutting carbon steel nitrogen consumption is very large, the thicker the stainless steel nitrogen consumption and purity are very high, the cost is relatively large.

The auxiliary gas of laser cutting machine is mainly used in:

1. Laser gas (gas used to generate laser in laser generator)

2. Compressed air (generally used to protect the light path, some manufacturers also used to do protective gas)

3. Auxiliary gas (gas ejected from the cutting nozzle of the cutting machine)

For cutting carbon steel, the purity of oxygen is generally 99.5% or higher. The main function is to aid combustion and blow off the cutting slag. The pressure and flow of each laser cutting machine manufacturer is different, 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. Flow is not easy to say, such as cutting 22mm carbon steel, some manufacturers of flow to reach 10M3/h(including double cutting nozzle protection with oxygen)

Nitrogen is used to cut stainless steel. The function is to prevent oxidation reaction and blow off slag. There are high requirements for the purity of nitrogen (especially for stainless steel above 8mm, the purity of 99.999% is generally required). The pressure requirements are relatively large, generally requiring more than 1Mpa, such as cutting more than 12mm, or thicker to 25mm stainless steel, requiring higher pressure, more than 2Mpa or higher. The flow varies according to the model of the cutting nozzle, but it is very large. For example, some manufacturers want to cut 12mm stainless steel 150m3/h and 3mm, as long as the flow below 50m3/h.

Laser welding machine in the welding process will use a protective gas, protective gas is through the nozzle mouth at a certain pressure to reach the surface of the workpiece, but many people do not know why to use protective gas, the following by the gas technician of Shengyuejia to explain to you why to use protective gas when laser welding machine welding:

Reason 1: It can protect the focusing lens from metal vapor contamination and liquid droplet sputtering

Shielding gas can protect the laser welding machine focusing lens from metal vapor pollution and liquid droplet sputtering, especially in high power welding, because the ejecta becomes very powerful, at this time the protection lens is more necessary.

Reason 2: the shielding gas is very effective in dispersing the plasma shielding generated by high power laser welding

The metal vapor absorbs the laser beam and ionizes into a plasma cloud. The shielding gas around the metal vapor also ionizes due to heat. If there is too much plasma, the laser beam is consumed by the plasma to some extent. As the second energy, plasma exists on the working surface, which makes the melting depth shallower and the welding pool surface wider. The recombination rate of electrons is increased by increasing the three-body collisions of electrons with ions and neutral atoms to reduce the electron density in the plasma. The lighter the neutral atoms are, the higher the collision frequency is and the higher the recombination rate is. On the other hand, only protective gases with high ionization energy do not increase the electron density due to the ionization of the gas itself.

Reason 3: the protective gas can make the workpiece in the welding process from oxidation

Laser welding machine must use a gas for protection, and the program should be set to the first out of the protective gas and then out of the laser, to prevent continuous processing, pulse laser oxidation phenomenon. The inert gas can protect the molten pool, when some materials welding does not care about the surface oxidation is not considered protection, but for most applications are often used helium, argon, nitrogen and other gases for protection, so that the workpiece in the welding process from oxidation.

These are the reasons why the protective gas is used when the laser welding machine is welded. Generally, helium is used as protective gas, which can suppress plasma to the greatest extent, thus increasing the depth of penetration and improving the welding speed; And light weight can escape, not easy to cause pores. Of course, from our actual welding effect, the effect of argon protection is also good.