How to control the cutting quality of optical fiber laser cutting machine, we consulted the operating engineer of Chuyu Optoelectronics and summarized the following five points:
1. Effect of focus position adjustment on cutting quality
Because the laser power density has a great influence on the cutting speed, the selection of lens focal length is an important issue. After the laser beam is focused, the spot size is proportional to the focal length of the lens. After focusing with a short focus lens, the spot size is very small, and the power density at the focus is very high, which is very conducive to material cutting. But its disadvantage is that the focal depth is very short and the adjustment margin is very small, which is usually suitable for high-speed cutting thin materials. Because the long focal length lens has a wide focal depth, it is more suitable for cutting thicker workpieces as long as it has sufficient power density.
In the whole cutting process, it is an important condition to ensure that the relative position of the focus and the workpiece is constant to obtain stable cutting quality. Sometimes, the lens is heated due to poor heat dissipation during operation, which leads to the change of focal length, so it is necessary to adjust the focal length in time.
When the focus is in a good position, the gap is smaller, the efficiency is higher, and a good cutting speed can obtain a good cutting effect. In most applications, the beam focus is adjusted just below the nozzle. The distance between the nozzle and the workpiece surface is usually about 1.5mm.
2. Influence of cutting speed on cutting quality
For a given laser power density and material, the cutting speed conforms to the empirical formula. As long as the cutting speed is higher than the passing threshold, the cutting speed of materials is proportional to the laser power density, that is, increasing the power density can improve the cutting speed. The power density mentioned here is not only related to the laser output power, but also to the beam quality mode. In addition, the characteristics of the beam focusing system, that is, the size of the focus, also have a great impact on laser cutting.
Especially for metal materials, under the condition that other process variables remain constant, the laser cutting speed can have a relatively adjustable range and still maintain a satisfactory cutting quality. When cutting thin metal, the width of this adjustment range seems to be slightly larger than that of thick parts. Sometimes, the slow cutting speed will cause the discharged hot melt material to ablate the opening surface, making the cutting surface very rough.
How to control the cutting quality of laser cutting machine?
3. Influence of laser output power on cutting quality
For CW output fiber laser source, the laser power and mode quality will have an important impact on the cutting. In actual operation, higher power is usually set to obtain higher cutting speed or cut thicker materials. However, the beam mode (the distribution of beam energy on the cross section) is sometimes more important, and when the output power increases, the mode usually becomes slightly worse. In the whole effective working life of the laser, the mode is inconsistent. The mode mechanism is affected by the condition of optical components, subtle changes of laser working gas mixture and flow fluctuation.
4. Impact of cutting procedure on cutting quality
According to the technical requirements of the product, it is very important to develop appropriate cutting procedures. In the daily production and processing process, we may need to use optical fiber laser cutting machine to cut different patterns, and need different cutting technologies. Our operators need to set up appropriate cutting procedures according to different cutting technologies to obtain a good process in a short time.
5. Impact of layout scheme on cutting quality
On the premise of quality assurance, excellent layout scheme must be formulated. When obtaining raw materials, we should first consider how to reduce cutting paths, avoid repeated cutting, and improve cutting efficiency.
To sum up, cutting speed, focus position and laser output power, cutting program and layout plan are five very important variables. In the cutting process, if the cutting quality is obviously poor, the above factors must be checked and adjusted in time.