1.5kw fiber laser cutting machine use different auxiliary gases to cut different materials. The thickness of the cutting material is different, the pressure of the auxiliary gas and the required flow are not the same, the pressure of the auxiliary gas has a direct impact on the results of laser cutting. The working gas of the laser is used to produce the laser; Protective gas is used to protect optical devices and drive optical gates. The working gas of the laser is mixed with helium, nitrogen and carbon dioxide in a certain proportion, which is predetermined in the factory to ensure the best performance. The auxiliary gas can not only blow away the slag in time, but also play a role in cooling the workpiece and cleaning the lens. The selection of different auxiliary gas can change the cutting speed and the quality of the slit surface, which is of great significance to the cutting of special metals. The auxiliary gas types include oxygen, air, nitrogen and argon. Air nitrogen as a protective gas when cutting can prevent the occurrence of oxidation film; Argon is used for cutting titanium.
1. Compressed air.
Air is suitable for cutting aluminum, non-metal and galvanized steel sheets. To a certain extent, it can reduce oxide film and save costs. Generally, it is used when the cutting plate is not relatively thick and the cutting end face is not too high. It is used more in some sheet metal cabinets, cabinets and other product industries.
Nitrogen is an inert gas, which prevents the oxidation of the cutting end face of the product and prevents combustion (which is easy to occur when the sheet material is thick). Nitrogen can be selected for products with higher requirements for cutting end face and exposed without treatment. Such as some decoration industry, aerospace and other special parts;
Oxygen mainly plays a combustion-supporting role, which can make the cutting speed faster and the cutting thickness thicker. Oxygen is suitable for thick plate cutting, high speed cutting and very thin plate cutting, such as some large amount of carbon steel plate and some thicker carbon steel laminating components, can use oxygen.
Increasing the gas pressure can improve the cutting speed, but after reaching a maximum, continuing to increase the gas pressure will cause a decrease in the cutting speed. Under high auxiliary gas pressure, the decrease of cutting speed can be attributed to the enhancement of cooling effect of high airflow velocity and the interference of intermittent shock wave in the airflow on cooling effect of laser area.
The uneven pressure and temperature in the airflow will cause the change of the airflow field density. Such a density gradient results in a change in the refractive index of the field, which dries up the focus of the beam energy, resulting in refocus or divergence of the beam. This interference will affect the melting efficiency and may sometimes change the mode structure, resulting in reduced cutting quality if the beam diverges too much. If the spot is too large, it may even cause serious consequences of not being able to cut effectively.