How to choose the Gas when use fiber laser cutting machine
The laser cutting machine needs to be equipped with auxiliary gas, mainly oxygen, nitrogen and air.
When the optical fiber laser cutting machine is processing the workpiece, it will be irradiated by the laser focus spot, and the irradiated area will be instantly melted and gasified. Then, the laser spot position can be moved through the CNC 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.Generally, it is used when the cutting plate is not relatively thick and the requirements for cutting end face are not too high.
2. Nitrogen.
It is easy to prevent burning of inert gas when cutting the end face of the product.Nitrogen can be used for the products with high requirements for cutting end face and exposed without treatment.
3. Oxygen.
Oxygen mainly plays a role in combustion, it can make the cutting speed faster, cutting thickness thickening.Oxygen is suitable for thick plate cutting, high speed cutting and thin plate cutting. For example, oxygen can be used for some large amount of carbon steel plate and some thick carbon steel plate structural parts.
Increasing the gas pressure can improve the cutting speed, but after reaching a set value, increasing the gas pressure will cause the cutting speed to decrease.Under high auxiliary gas pressure, the reason for the decrease of cutting speed can be attributed to the enhancement of cooling effect of high air velocity and hanging action zone, and the interference of intermittent shock wave in the gas flow on laser action zone cooling.
The uneven pressure and temperature in the air flow will cause the change of air field density.Such a density gradient leads to the change of the refractive index in the field, which results in the focusing of the beam energy, resulting in refocusing or beam divergence.This kind of interference will affect the melting efficiency, sometimes it may change the mode structure, resulting in the decline of cutting quality, if the beam divergence is too large.If the light spot is too large, it will even cause serious consequences that the cutting can not be carried out effectively.
Application of auxiliary gas:
1. Compressed air: it is widely used in processing some sheet metal chassis, cabinet, cabinet and other products.
2. Nitrogen: processing some decoration industry, aerospace and other parts;
Laser cutting machine uses different auxiliary gases to cut different materials.The pressure and flow rate of auxiliary gas vary with the thickness of cutting material.
