There are many factors that affect the cutting quality of the laser cutting machine. Cutting speed, gas pressure, cooling water temperature, whether the lens is clean, etc. will affect the cutting speed and cutting quality. Today, I will focus on the focus lens focal length and focus position on the cutting quality. Impact.

First teach you how to choose a focusing lens for different thicknesses:

In general, short-speed lenses should be selected for high-speed cutting of stainless steel below 3mm, and short-focus or long-focus lenses for 3-8mm stainless steel can be selected. For cutting stainless steel or carbon steel above 8mm, telephoto lenses are recommended. It is thought that the focal spot size of the short focus lens is small (the size of the focused spot of the laser beam is proportional to the longer lens), the power density at the focal point is high, and the cutting speed is fast (the cutting speed of the material is proportional to the laser power density). It is good for material cutting, but its shortcomings are also obvious. First of all, the adjustment margin is small. For cutting thicker plates, the width of the upper and lower cuts will be different, which affects the cutting quality. At the same time, because the cutting power density is concentrated and the slit is thinner, slag will splash on the lens surface when cutting the plate, which affects the service life of the lens. Therefore, short focal length lenses are generally used for high-speed thin-plate cutting.

The focal spot power density of the telephoto lens is low, but its focal depth is large. As long as the total power of the laser is large enough, the advantages of cutting thick plates are prominent.

Now let ’s talk about the effect of the focus position on cutting. After the operator determines which focal length lens to use, how to adjust the focus position becomes the most important factor affecting the cutting speed and quality. Generally, when adjusting the focus, try to ensure that the relative position of the focus and the workpiece is constant. At present, major cutting head manufacturers have introduced automatic focusing cutting heads. Based on this principle, the focal length of the lens always follows the fluctuation of the workpiece and automatically adjusts the focus to the middle of the workpiece thickness. . Sometimes the focal length changes due to poor cooling during the work of the lens, and the automatic focusing is not accurate. This is necessary to correct the focus position so that the focus is on the surface of the workpiece to obtain better cutting results.