Research on Causes and Solutions of Lens Pollution in Fiber Laser Cutting Machine Head
With the rapid development of sheet metal processing technology, fiber laser cutting machines, especially fiber laser cutting machines, have become the mainstream processing equipment in this field. The market demand is increasing exponentially, and the market share continues to increase. At the same time, this type of equipment has also exposed its defects in a large number of practical applications. The typical case is that the optical lens inside the cutting head is easily contaminated, resulting in scrapped parts and even short-term damage to the lens, which has become a bottleneck affecting the further rapid development of the equipment. This article focuses on the anti-pollution methods of the cutting head lens to increase the service life of the lens, reduce maintenance and repair costs, and improve processing efficiency.
Currently, most of the cutting heads used in fiber laser cutting machines on the market are the LightCutter cutting head and ProCutter cutting head (Figure 2) of German PRECITEC. The applicable laser power range of the two cutting heads is: LightCutter≤2500W, Procutter≤6000W.
Analysis of the pollution process of the cutting head
The optical components in the cutting head are 2 collimator lenses, 3 focusing lenses, and 4 protective lenses. The pollution of these lenses directly affects the cutting process of the machine tool.
According to the long-term process test and the analysis of a large number of customers, the main factors that cause the cutting head pollution are as follows: ①Improper installation method of the optical fiber head; ②The sealing effect of the cutting head is not good; ③Replace the protective lens, O-rings, etc.); ⑦Improper operation and use by the final customer; ⑧Improper maintenance and repair methods of the cutting head.
3 Anti-pollution research of cutting head
It is difficult for us to make the cutting head pollution-free, but we can extend the pollution time and reduce the pollution degree through some methods, so as to increase the service life of the cutting head and reduce Its maintenance and repair costs. In view of the pollution factors listed above that cause the lens of the cutting head, the corresponding measures can be taken as follows:
Improve the installation method of the optical fiber head, improve the installation method, and make the optical fiber head horizontally inserted into the inside of the cutting head and Lock tightly. Note that the surrounding environment should be as clean as possible. If there are many suspended particles (dust) around, it is recommended to carry out this work at 6:00 in the morning before going to work.
Improve the sealing effect of the cutting head
According to the current level of mechanical manufacturing, even with the more advanced German technology, the laser cutting head cannot be completely sealed. In the later use process In this case, dust will inevitably enter and contaminate the lens. The reason is that the temperature of the cutting head increases during the cutting process (normal cutting is possible when the temperature of the cutting head is less than 55°C), and the internal air pressure increases, and part of the gas inside will be forced out of the cutting head and emitted into the surrounding environment. After the cutting head stops working (after the worker gets off work), when the internal temperature drops to the ambient temperature, the internal air pressure is lower than the ambient air pressure, and the dust-containing gas from the outside will be pressed into the cutting head until the internal and external air pressures balance, and the cutting head will be contaminated. Up. The idea to solve this problem is to keep the internal air pressure of the cutting head always at a positive pressure (greater than the ambient air pressure) to isolate the environment from dust and gas from entering the cutting head.
The improvement methods of fiber laser cutting machine are as follows:
①Always pass clean, dry and oil-free gas into the cutting head (nitrogen is recommended, 0.15bar≤pressure＜0.3bar);
②Install a breathing system, and always keep the inside of the cutting head at a positive pressure.
Fiber laser cutting machine correctly replace the protective lens
Fiber laser cutting machine requires quick replacement of the protective lens, and when the protective lens window box is drawn out, the cutting head should be sealed with paper tape immediately The upper window (cutting the installation opening of the protective lens window box), in addition, do not allow dirty things to touch the protective lens, and the operator cannot speak (to prevent saliva from splashing on the protective lens).