Fiber laser cutting machine has become the mainstream equipment for metal project manufacturing, in which laser cutting head is the core component of fiber laser cutting machine. The high-power fiber laser cutting head generally consists of a nozzle, a focusing mirror, an auxiliary system and a focus tracking detection system.
The nozzle is generally coaxial with the fiber laser cutting head and has various shapes. When choosing the nozzle, its diameter must be larger than the focused beam, i.e. the laser beam cannot hit the wall as it passes through the nozzle.
Nozzle size is not the same. Large-diameter nozzles do not have very strict requirements on focusing the laser beam. The smaller diameter nozzle has higher requirements for the focused beam, and it is necessary to ensure that the collimation and diameter of the laser beam can perfectly fit the nozzle diameter. In the actual application process, it is very important to choose the appropriate diameter, because the outlet of the auxiliary gas is also in the nozzle part. If the diameter is too small, the airflow of the nozzle will be disturbed; if the diameter is too large, the nozzle will be partially deformed due to high temperature.
The focusing mirror is located just above the nozzle, and its main function is to focus the beam to obtain a spot with dense energy. The focusing mirror can be divided into two types: transmission and reflection. Among them, the transmission mirror is generally used in the transmission type laser head; the reflector is generally used in the reflection type laser head. The material selection range of the lens is relatively wide, among which the zinc selenide material is the first choice for the lens material due to its ultra-high light transmittance and the lowest light absorption rate.
Under normal circumstances, the smaller the focal length of the focusing lens, the smaller the diameter of the spot after focusing, and the shallower the depth of focus. When the fiber laser cutting machine
processes thick sheet metal, the shallow depth of focus will seriously affect the cutting quality, resulting in burrs and burrs. Not only that, the shallow depth of focus will shorten the distance between the cutting head and the metal plate, and the slag will easily penetrate into the laser head and have a bad influence. So, we should try to use the proper focal length for the post-cutting procedure. You can follow the suggestions below:
When the thickness of the metal plate is large, a larger focal length and enhanced laser power can be used to alleviate the state of weak spot energy; when the thickness of the metal plate is small, a small focal length can be used to achieve high-speed cutting.
Auxiliary system includes water cooling system, auxiliary gas and protective gas curtain
The water cooling system cools the fiber laser cutting head without affecting the cutting efficiency and cutting quality, and protects it from normal operation. Auxiliary gas can assist combustion or prevent metal slag, and different auxiliary gases play different roles. Therefore, when cutting different metal sheets, different auxiliary gases need to be selected. When cutting active metals, inert gas is often used to prevent additional heat from affecting the cutting effect. On the contrary, use active gas to increase thermal cutting.
Focus Tracking Detection System
The focus tracking detection system is to ensure a stable focus spot. According to different requirements, different functional detection devices are installed on the cutting head to maintain a low cutting error rate.
The above are the main components and functions of the fiber laser cutting head. For more information on fiber laser cutting machine
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