Thelaser cutting machine needs to be equipped with auxiliary gases, mainly oxygen, nitrogen and air. When processing the workpiece, the optical fiber laser cutting machine will be irradiated by the laser focus spot, and the irradiated area will be instantly melted and gasified, and then the spot irradiation position will be moved through the numerical control equipment system to realize automatic cutting.
1. Compressed air
Air is suitable for cutting aluminum plate, and galvanized steel plate. To some extent, it can reduce oxide film and save cost. It is generally used when the cutting plate is relatively thick and the requirements for the cutting end face are not too high.
Nitrogen is an inert gas, which can prevent oxidation and combustion of the cutting end face of the product during cutting (it is easy to occur when the plate is thick. Nitrogen can be selected for products with high requirements for the cutting end face and exposed without treatment.
Increasing the gas pressure can improve the cutting speed, but after reaching a set value, continuing to increase the gas pressure will reduce the cutting speed. Under high auxiliary gas pressure, the reason for the decrease of cutting speed can be attributed to the enhancement of the cooling effect of the hanging action zone by high gas flow velocity, and the interference of intermittent shock wave in the gas flow on the cooling of the laser action zone.
The uneven pressure and temperature in the air flow will cause the change of air flow field density. Such a density gradient leads to the change of the refractive index in the field, thus drying the focusing of the beam energy, resulting in refocusing or beam divergence. This interference will affect the melting efficiency. Sometimes, the mode structure may be changed, resulting in the decline of cutting quality. If the beam divergence is too large. Make the light spot too large, and even cause the serious consequences of not cutting effectively.
Application of auxiliary gas:
1. Compressed air: it is widely used in the processing of some sheet metal chassis, cabinets, cabinets and other products.
2. Nitrogen: processing some decoration industries, aerospace and other parts;
Laser cutting machines use different auxiliary gases to cut different materials. The pressure and required flow rate of auxiliary gas vary with the thickness of cutting material.