As we all know, the laser cutting machine has incomparable advantages in cutting metal plates. It not only has high cutting accuracy, but also has smooth cross section without burrs. It can achieve good results in cutting thick plates or thin plates. However, these effects are inseparable from the focus control of the laser cutting machine. It is a principle to achieve better imaging results with the focusing of the SLR camera.

So, what is focus control? Those who are familiar with the laser cutting machine know that when the laser cutting machine is cutting different materials and plates of different thicknesses, in order to achieve better cutting effects, the focus of the laser beam will be set in different places (as shown in the figure), which is called focusing.

In the early application of laser cutting, focusing is mainly done by hand. Now, with the development of laser technology, this manual focusing method has been gradually eliminated, and the automatic focusing function has been gradually realized. For example, all series of laser cutting machines with high energy lasers are equipped with full automatic focusing function. Then, some people will say that the light path is integrated in the cutting head, and the focusing function can be realized by changing the height of the cutting head? When the cutting head is raised, the focus position is high, and when the cutting head is lowered, the focus position is low. However, it turns out that it is not as simple as you think (as shown in the figure below).

The bottom of the cutting head is the nozzle. During the cutting process, the distance between the nozzle and the workpiece (nozzle height) is about 0.5~1.5mm, which can be regarded as a fixed value, that is, the nozzle height remains unchanged, so the focus cannot be adjusted by lifting the cutting head (otherwise, the cutting process cannot be completed).

The focal length of the focusing mirror is unchangeable, so it can not be expected to focus by changing the focal length. If you change the position of the focusing mirror, you can change the focus position: if the focusing mirror drops, the focus drops, and if the focusing mirror rises, the focus rises& mdash;& mdash; This is really a way of focusing. Auto focusing can be realized by using a motor to drive the focusing mirror to move up and down.

Another automatic focusing method is to set a variable curvature mirror (or adjustable mirror) before the beam enters the focusing mirror, and change the divergence angle of the reflected beam by changing the curvature of the mirror, thus changing the focus position. As shown in the figure below.

With the auto focusing function, the machine can automatically quickly adjust the focus to the most appropriate position when processing workpieces of different materials and thicknesses. This can significantly improve the processing efficiency of the laser cutting machine, and the thick plate perforation time will be greatly reduced.

Therefore, for laser cutting machine, auto focusing function is an important and indispensable function.