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Advantages of automatic focusing of laser cutting machine

  • source:metmac;
  • Time:04/14/2021

Laser cutting metal sheets has unparalleled advantages. It not only has high cutting accuracy, but also has a smooth cross section without burrs. Both thick and thin plates can obtain good cutting results. However, these effects cannot be separated from the focus control of the laser cutting machine. And using the focus of the SLR camera to obtain a better imaging effect is the same principle.

Exchange table fiber laser cutting machine


What is focus control? Friends who are familiar with laser cutting machines know that when the laser cutting machine cuts different thicknesses and materials and metal plates, in order to obtain a better cutting effect, the focus of the laser beam will be set in different places, which we call focus.

In the early days of laser cutting applications, the main method of focusing was done manually. Now with the development of laser technology, this manual focusing method has been gradually eliminated, and the automatic focusing function has begun to be slowly realized. For example, a full range of high-energy laser cutting machines All are equipped with a fully automatic focusing function. Then, someone would say that the optical path has been integrated into the cutting head, so the focus function can be achieved by changing the height of the cutting head? When the cutting head rises, the focus position is high, and when the cutting head goes down, the focus position is low. However, it turns out that it is not as simple as imagined.

The bottom of the laser cutting head is the nozzle. During the cutting process, the distance between the nozzle and the workpiece (nozzle height) is about 0.5 to 1.5 mm, which may be regarded as a fixed value. The nozzle height is unchanged, so it is impossible to focus by lifting the cutting head (otherwise the cutting process cannot be completed).

Supplying laser cutting nozzles, lens and ceramics


The focal length of the focusing lens cannot be changed, so you cannot focus by changing the focal length. If the position of the focusing lens is changed, the focus position can be changed: if the focusing lens is lowered, the focus is lowered, and if the focusing lens is raised, the focus is raised. This is indeed a feasible way of focusing. Automatic focusing is achieved by using a motor to drive the focusing lens 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, thereby changing the focus position.


 Through the automatic focus function, when processing workpieces of different materials and thickness, the machine can automatically and quickly adjust the focus to the most suitable position. In this way, the processing efficiency of the laser cutting machine can be significantly improved, and the perforation time of the thick plate can also be greatly reduced.

 Therefore, for laser cutting machines, the auto focus function is an important and indispensable function.