The slit of laser cutting machine is too narrow, resulting in increased heat loss. Laser cutting is mainly in the form of heat conduction. The greater the thickness, the greater the heat loss, resulting in the reduction of cutting speed.
There are many slag hanging at the bottom of the cutting section. The formation of slag hanging is not only caused by the low average cutting temperature at the bottom of cutting, but also due to the large energy loss. In this case, the quality of cutting is usually not high.
Fiber laser has small spot diameter and limited focal depth. Taking the fiber laser cutting machine as an example, although it can maintain a high laser power density in the cutting depth, it is not conducive to cutting and slag removal due to the small beam diameter and small cutting seam. This not only puts forward higher requirements for the collimation mode and collimation range of fiber laser speckle beam scattering, but also brings great difficulties to the processing quality of medium and thick metal plates cut by fiber laser.
Influence of mass and pressure of auxiliary gas. Oxygen plays an important role in fiber laser cutting carbon steel plate. Laser irradiation forms small holes on the surface of the workpiece. When the laser beam moves along the cutting direction, there is oxidized melt around the hole and slit. The purity and pressure of oxygen have a great influence on laser cutting. The oxygen with many impurities and inappropriate pressure can not provide enough energy to the cutting bottom, form a melt with high fluidity, and reduce the cutting quality and cutting speed.
By measuring the mass and pressure of auxiliary gas at different slit positions, it is found that the narrower the slit is, the worse the effect of auxiliary gas is, and the more difficult it is to maintain the cutting quality. Therefore, it is very important to ensure the appropriate slit width, the quality of auxiliary gas and the pressure control of cutting quality. The difference of geometry reduces the cutting quality of inflection point. When laser cutting thick plates, the inclination angle before melting will become prominent, which will reduce the laser absorption coefficient of the material, so as to ensure the cutting quality by increasing the cutting power and reducing the cutting speed.
Laser cutting machine will be widely used in cutting field because of its high point conversion, high cutting accuracy, flexible processing ability, good cutting quality and adaptive performance.
