I vaporization cutting
It means that the removal of the processed material is mainly carried out by vaporizing the material.
In the vaporization cutting process, the workpiece surface under the action of the focused laser beam, the temperature rapidly rises to the vaporization temperature, the material is vaporized in a large amount, and the formed high-pressure vapor ejects at a supersonic speed. At the same time, “holes” are formed in the laser-induced area. The multiple reflections of the laser beam in the holes increase the absorption of the laser material.
During the high-pressure steam high-speed injection, the molten material in the slits is simultaneously blown away from the slits until the workpiece is cut. Internal vaporization cutting is mainly carried out by vaporizing the material. Therefore, the required power density is high, and it should generally reach 10 octave square or more per square centimeter.
Vaporization cutting is a method of laser cutting some low fired materials (such as wood, carbon, and some plastics) and infusible materials (such as ceramics). Vaporized cutting is also used when cutting materials with a pulsed laser.
II reactive melt cutting
In the melt cutting, if the auxiliary air flow is not only to blow away the melt in the slit, but also can react with the workpiece to change heat, so that the cutting process adds another - heat source, such cutting is called reactive melt cutting. The gas that normally reacts with the workpiece is oxygen or a mixture containing oxygen.
When the surface temperature of the workpiece reaches the ignition temperature, a strong combustion exothermic reaction occurs, which can greatly improve the ability of laser cutting. For low carbon steel and stainless steel, the energy provided by the exothermic combustion reaction is 60%. For titanium and other active metals, the combustion provides about 90% of the energy.
Therefore, compared with laser vaporization cutting and general melting cutting, reactive fusion cutting requires a lower laser power density, which is only 1/20 of vaporization cutting and 1/2 of fusion cutting. However, in reactive melt cutting, the internal combustion reaction will cause some chemical changes on the surface of the material, which will affect the performance of the workpiece.