How to control the blackening degree of laser cut wood?

　Laser cutting wood has the advantages of high precision, narrow cutting seam, fast speed and smooth cutting surface. However, because the laser focused energy melts the plate, blackening occurs during the cutting process, that is, the blade is carbonized. Today, let us talk about how to reduce or even avoid this situation.

    The first thing to note is that if the cutting board is thick, it is difficult to avoid blackening. After my tests and conclusions, template cutting with a thickness of 5mm or less can achieve less blackening, while template cutting with a thickness of 5mm or more depends on the situation.

    We all know that we should avoid the carbonization effect of laser cutting and use high speed and low power. This is correct, but there are some misunderstandings. They think that the faster the better, the lower the better. In order to reduce blackness, they cut multiple times at a faster speed and lower power. This is bad. The carbonization effect may be deeper than the general carbonization effect.

    How to avoid blackening when laser cutting wood

    Our low power and fast must be able to cut the wood at the same time. The faster the wood is cut, the better the power. However, if it needs to be cut multiple times to reduce power, carbonization is actually more serious. Because the cut part will be burnt twice, the more cut, the more severe the charring. The first cutting part was burned again in the second cutting process. The other part, because it was not cut off for the first time, was not so dark. So what we need is cutting, not the second processing.

    However, high speed and low power are contradictory. The faster the speed, the harder it is to pass, and the lower the power, the harder it is to pass. We need to prioritize between the two. According to our experience, fast speed is more important than low power consumption. Try to cut off the fastest speed with high power. Of course, this requires testing to get the best value.

    Of course, in addition to the effect of power speed on blackening, there is another very important factor, which is blowing. When felling wood, you must blow hard. It is better to use an air compressor, because another blackening and yellowing factor is that the gas produced by cutting is fumigated, and blowing can help cutting, making cutting easier and preventing fire. In actual production, the flatness of the lower platform, the laser focal length problem caused by the uneven plate, the uneven glue problem of the composite plate and the cutting problem caused by the composite plate material should be considered. Therefore, limit cutting materials must not be used in actual production, and it is very likely that the cutting will be impermeable. Air pressure is necessary to reduce blackening.

 

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    Let you immediately understand the four characteristics of laser.

    Since the invention of laser, with its own excellent characteristics, it has been widely used in industrial processing, medical beauty, scientific research and other fields. The laser has the characteristics of high brightness, good directionality, good monochromaticity, and good coherence.     These characteristics are interrelated, so the laser can be used in different scenarios.

    High brightness laser

    The high brightness of the laser is mainly due to its highly focused beam. The high brightness of the laser is also a manifestation of its high energy concentration. After the lens is focused, a high temperature of thousands or even tens of thousands of degrees is formed near the focal length, making it able to process almost all materials.

    High energy concentration is a very important characteristic of lasers. Due to its advantages, it can be widely used in industrial processing and medical fields.

    Monochromaticity

    The color of light is determined by the wavelength of light, and light has a certain wavelength range. The narrower the wavelength range, the better the monochromaticity. For ordinary light sources, due to the large spectral line width and the wide frequency range, the colors will be more  chaotic.

    Although compared with ordinary light sources, the spectral line width of laser is much narrower. However, the line width of the laser is restricted by many factors, and it is almost impossible to reach the theoretical level. For example, factors such as temperature changes, slight vibration of the laser, airflow in the volumetric optics, and external pumping can cause the resonant frequency to be unstable, which leads to a decrease in the performance of the system.

    Good direction

    The light emitted by ordinary light sources travels in all directions with a large divergence angle. On the contrary, the divergence angle of the laser is very small, and it is emitted almost in parallel. The light emitted by the laser is polarized light in a fixed direction. A simple example can express this intuitively: the laser does not refract water.

    Among various lasers, gas lasers are the most prominent in terms of directivity, followed by solid-state lasers. Semiconductor lasers are slightly inferior to semiconductor lasers in this respect.

    Good consistency

    Light waves are composed of many photons. Due to the resonance principle, the photons emitted by the laser are consistent in wavelength, frequency, and polarization direction, which makes the laser produce strong interference force. We also call laser coherent light. This is because the coherence of lasers is much stronger than that of ordinary light sources.

    The use of laser as the light source of the hologram also has good coherence.