Le 28 décembre 2017 à 06:09
Rubriques : Laser Technology
The laser cutting machine uses different auxiliary gases to cut different materials.
The laser cutting machine uses different auxiliary gases to cut different materials. The thickness of cutting material is different. The pressure of auxiliary gas and the required flow rate are different. The pressure of auxiliary gas has a direct effect on the result of laser cutting. Laser working gases are used to produce laser pointer; protective gases are used to protect optical devices and drive sluice. Laser gas by helium, nitrogen and carbon dioxide are mixed according to a certain proportion, the proportion of reservation in the factory, to ensure the best performance; the auxiliary gas can timely slag blow away, also play a role and cooling the workpiece cleaning the lens, using different auxiliary gas, can change the cutting speed and the cutting surface quality the special metal cutting, is of great significance to assist gas type oxygen, air, nitrogen and argon. Air nitrogen is used as a protective gas for cutting to prevent oxide film from occurring, and argon is used for titanium metal cutting.
Compressed air. The air is suitable for cutting aluminum, non-metal and galvanized steel, to a certain extent it can reduce the oxide film and save the cost. In general the cutting plate is relatively thick, the cutting face requirements is not very high, in some metal cabinet cabinet products industry application.
Nitrogen. Nitrogen is an inert gas which prevents the oxidation of the cutting end of the product and prevents the combustion (when the material is thicker). Nitrogen can be selected for products that require high cutting end face and do not need to be treated. For example, some special parts such as decoration industry, aeronautics and Astronautics, etc.
Oxygen. Oxygen mainly plays the role of combustion, which can increase the speed of cutting and thicker the cutting thickness. Oxygen is suitable for thick plate cutting, high-speed cutting and very thin plate cutting. For example, some larger carbon steel plates and some thicker carbon steel structural parts can use oxygen.
Increasing the pressure of the gas can increase the cutting speed, but after reaching a maximum, increasing the pressure of the gas will cause the cutting speed to decrease. Under high auxiliary gas pressure, the reduction of cutting speed can not only be attributed to the enhancement of the airflow speed and the cooling effect of the hanging zone, but also to the interference of intermittent shock waves to the cooling zone of the burning laser zone.
There is an uneven pressure and temperature in the air flow, which will cause the change of the density of the airflow field. Such a density gradient leads to a change in the refractive index of the field, so as to draw the focus of the beam energy and cause the refocusing or the divergence of the beam. This interference will affect the melting efficiency, may sometimes change the mode structure, resulting in the decline in the quality of cutting, if the beam divergence is too much. Make the spot too large, and even cause serious consequences that can not be effectively cut.