The auxiliary gas of laser cutting machine usually includes oxygen, air and nitrogen. Different auxiliary gases are used for cutting different materials. According to the different thickness of the cutting material, the pressure and flow rate of the auxiliary gas are the same. The gas pressure of the auxiliary gas has a direct impact on the laser cutting effect. The auxiliary gas can blow away the slag in time when the laser cutting machine is running, cool the workpiece and clean the lens. Different auxiliary gases are suitable for cutting metal plates of different materials and thicknesses.
1. Oxygen
Oxygen has a strong combustion supporting effect, so it can speed up the laser cutting speed and thicken the cutting thickness. Oxygen is suitable for thick plate cutting, high-speed cutting and extremely thin cutting. For example, oxygen can be used for some large carbon steel plates and some thick carbon steel plate structural parts.
2. Nitrogen
When oxygen is used for cutting, an oxide film will be formed to improve the light speed spectral absorption factor of the reflective material, and the end face of the cut is easy to blacken or appear dark yellow. The use of oxygen will prevent the formation of oxide film. The non-oxidation cutting face can be directly welded and coated, and has strong corrosion resistance. The cut end face is white.
3. Air
The air contains about 20% oxygen, and the compressed air of the air compressor can be used without cost. However, the efficiency and quality of air assisted cutting are far less than oxygen. At the same time, a small amount of oxide film will appear on the cutting surface. It can be used for cutting metal materials such as aluminum, aluminum alloy, brass and electroplated steel plate.
Increasing the gas pressure of the laser cutting machine can increase the cutting speed, but after reaching a maximum value, continuing to increase the gas pressure will cause the cutting speed to decrease. Under high auxiliary gas pressure, the reason for the reduction of cutting speed can be attributed to the enhancement of cooling effect of high gas flow velocity on the laser action area, and the interference of intermittent shock wave in the gas flow on the cooling of the laser action area.