Cutting thick plates using laser cutting machine
The development and technological update of laser cutting machines are getting faster and faster, and many users will encounter many problems when cutting thick plates.
The slit is too narrow, resulting in increased heat loss. The reduction in cutting speed increases the heat loss in the cutting area. The main form of heat loss is heat conduction. The greater the thickness, the greater the heat loss and the lower the cutting speed.
The material removal at the bottom of the notch becomes inconsistent, even though the laser penetrates the thick plate and a large amount of slag is combined at the bottom. The formation of slagging is caused by the lower average cutting temperature at the bottom of the cutting, and it is also caused by the large energy loss. In this case, the quality of the cut is usually not high.
The fiber laser has a small spot diameter and a limited depth of focus. Taking the fiber laser cutting machine as an example, although it can maintain a high laser power density in the cutting depth. The small beam diameter and the small slit are not conducive to cutting and slagging. This puts forward higher requirements on the collimation method and collimation range of fiber laser speckle beam scattering. And it also brings great difficulties to the processing quality of fiber laser cutting medium and thick metal sheets.
The influence and influence of the quality and pressure of the auxiliary gas. Oxygen; Oxygen plays an important role in fiber laser cutting of carbon steel medium and thick plates. 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 unsuitable pressure can not provide enough energy to the cutting bottom, forming a fluid with high fluidity, and reducing the cutting quality and cutting speed.
By measuring the quality and pressure of the auxiliary gas at different slit positions, it is found that the narrower the slit, the worse the effect of the auxiliary gas and the more difficult it is to maintain the cutting quality. Therefore, it is very important to ensure proper slit width, auxiliary gas quality and pressure control for cutting quality. The difference in geometry reduces the cutting quality at the inflection point. When laser cutting thick plates, the melting forward angle will become prominent, which will reduce the laser absorption coefficient of the material, thereby ensuring the cutting quality by increasing the cutting power and reducing the cutting speed.
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