Views: 39 Author: Site Editor Publish Time: 08-23-2021 Origin: Site
Nowadays, the application range of fiber laser cutting machine in the industrial processing field is more and more extensive, how to play the role of laser cutting machine to a greater extent? This requires us to know the laser cutting machine very well. With the gradual application of higher power lasers, a series of new problems will appear, which will affect the stability of laser processing, such as the thermal lens effect. So, how to avoid and solve the influence of thermal lens effect on laser cutting processing? Leapion laser tells you below.
When the optical elements (such as processing lens, PR mirror or window, etc.) through which the laser beam of the laser cutting machine passes are stained, the thermal lens effect will occur after the laser beam passes through, and the cutting surface will become rough as a result, and dross will appear, or even Burns will also occur.
When the processing quality of the laser cutting machine deteriorates, when judging whether it is affected by the thermal lens effect, first check whether the performance of the optical element changes with the irradiation time of the laser beam. At the beginning of processing, the optical element is still in a low temperature state, and as the processing progresses, the influence of the thermal lens effect will be manifested in the quality of the cut surface.
During the laser cutting process, for reflective optical elements, efficient cooling can be done directly from the back side, and there are few such optical elements, and no thermal effects will occur, so this kind of light-transmitting optics Components can only be gradually cooled by cooling the environment around them.
Both surfaces of optical components generate heat, and it is easy to produce a thermal lens effect. Relatively speaking, their temperature is certain when they rise. There will be some thermal deformation, so this laser cutting mode will more or less change the refractive index.
1. Stainless steel cutting: When cutting stainless steel, the thermal lens effect will cause the cutting surface to be inconsistent, more and more slag, and even continuous cutting problems.
2. Carbon steel cutting: When carbon steel is cutting, the thermal lens effect will cause more and more slag at the bottom and continuous cutting problems.
1. Compare the cutting surface at the beginning and the end of the workpiece processed by the laser cutting machine.
At the beginning of the process, because the laser beam is irradiated for a short time and the optical element is still in a low temperature state, the influence of the thermal lens effect is relatively small. At the end of the processing when the cutting time requires more than 10s, because the optical element is irradiated by the laser beam for a long time, a thermal lens effect will occur, and the focus position and beam pattern will also change.
Once the focus position changes or the beam pattern changes, it will not automatically return to the original state during continuous irradiation processing. Comparing the cutting surface at the beginning and the end of the process, the quality at the end of the process becomes worse. It means that the thermal lens effect has occurred; if the two qualities are of the same degree of good condition, it means that the thermal lens effect has not occurred.
2. The laser cutting machine processes stainless steel materials to determine whether the thermal lens effect has occurred
At this time, we need to observe the slagging conditions at the beginning and the end of the processing. If the amount of burrs at the processing place increases, it means that the thermal lens effect may have occurred. In addition, in order to eliminate the directionality caused by other reasons such as the unevenness of the beam pattern or the tilt of the optical axis, it should be noted that the same cutting surface (same processing direction) must be selected for comparison.
1. In the production process, in order to avoid the thermal lens effect, check the cleaning condition of the laser output head before installation, whether the lens or crystal is dirty or damaged, if any, clean and replace it;
2. It is necessary to check whether the protective lens, collimating chip set, and focusing lens set of the cutting head are of poor quality, dirty or damaged. If so, clean the lens or replace the good quality lens.
For more professional questions about laser cutting machines, please consult Leapion Laser, Leapion Laser 7×24 hours online service.
