With the change of industrial production demand, laser cutting as a processing method has been accepted by more and more sheet metal producers. In the whole plate processing of domestic steel, the phenomenon of poor processing in local areas often occurs. Laser cutting machine is regarded as an important means to promote the upgrading of traditional industries, but it still faces the huge bottleneck of insufficient application and backward core technology.
Especially in the process of cutting thick metal plates, the cutting speed will drop significantly, and the repeatability of the incision is poor, which makes it impossible to compete with traditional technologies. This phenomenon is sometimes very random, even when the processing machine is in good condition, which greatly affects the whole work progress in order to deal with local faulty products. If the laser cutting machine can overcome the difficulties in the thick plate cutting process, it will undoubtedly have a greater market prospect.
The cutting section is often encountered when processing medium and thick plates. Such cutting is not only questioned about the quality of the finished products, but also accompanied by excessive burning and serious slag, so that it does not reflect the value of the high-priced laser processing machine from other cutting methods. However, if a small power pulse is used for piercing, the time will be very long (12 seconds), which will lead to the reduction of cutting efficiency and unit cost
Improvement.
Piercing time accounts for a large proportion in thick plate processing, and various laser manufacturers have developed rapid piercing technology. The most representative is high-energy piercing, which has the advantage of high speed. However, the defect is that the huge energy injected during piercing makes the temperature of the plate rise and affect the subsequent overall cutting process, and affects the processing of small shapes.
For carbon steel, the important factor to improve the cutting section is to control the heat input to the plate and ensure the full combustion of the laser irradiated part. For stainless steel, the important factors to improve the cutting section are the improvement of the beam (improving the focal depth) and the effective use of auxiliary gas. The bright cutting technology is the result of improving the vibration generator and nozzle. Gu Ming’s idea of peak perforation is to use the peak value pulse laser with a small duty cycle, supplemented by non-fuel sprayed on the surface of the material to remove the attachment at the edge of the opening, and control the reasonable frequency of the pulse while cooling and piercing.
At present, in order to improve the operating speed of the processing machine, the metal laser cutting machine mostly adopts the structure commonly known as the flying light path, that is, the material tray does not move while the processing head moves in the whole machinable area. It is characterized by relatively long hole blasting time of 3 seconds, but small hole diameter (about φ 4mm) and there is no attachment at the edge of the opening and the heat input is low, which is convenient for the next normal cutting
The cutting efficiency is 4 times higher than that of ordinary piercing.
Although the structure of this method is simple, it will change the depth of focus, making it difficult to cut the medium and thick plate which is extremely sensitive to the depth of focus. The use of equal-length optical path can avoid the change of focal depth, so that the spot and focal depth are consistent. In addition, the importance of heat input can control the heat accumulated in the plate, and solve the stability problem better. In order to compensate the phase between the processing head and the light source
For the change of position, manufacturers also try to ensure the consistency of light spot within the processing range, and the use of curvature variable refractors is the common choice.
With the innovation of laser technology, the laser power applied to industrial production will also continue to grow. In the future, the metal laser cutting machine will break through the existing cutting thickness limit step by step, bringing more surprises to industrial production.
