Future-oriented laser cutting technology
Laser is one of the most important inventions of the twentieth century. With the development of technology, laser technology has been applied to various fields of industrial production, from aerospace to shipbuilding, from medical surgery to integrated circuit production, from mechanical manufacturing to clothing. Production... Different industrial fields, lasers have different solutions, laser cutting, welding, heat treatment, cladding, texturing, marking and so on. Among them, laser cutting accounts for about 70% of industrial laser applications (mainly for sheet metal cutting). First: the factors that affect the quality of laser cutting - optical articles Lasers are the heart of laser equipment and play a decisive role in the quality of laser cutting. A good laser should have the ideal mode, stable power and other elements. The laser with TEM00 mode can obtain the smallest beam diameter, and the smallest slit and faster cutting speed can be obtained in the cutting process because of its small spot size. The basic model is as follows: Two: laser frequency. The laser output is divided into pulse output and continuous output. The laser used for cutting and welding mainly adopts pulse output mode. The pulse frequency mainly affects the cutting speed and the roughness of the slit. To obtain high-speed cutting, high frequency is indispensable. At present, most manufacturers produce carbon dioxide lasers with frequencies below 5000 Hz. Next page
Laser cutting is known for its high speed, high precision and high incision finish. Combined with advanced CNC systems and machine tools, the laser has excellent performance in 2D and 3D cutting.
However, there are also many problems that confuse users, what kind of laser technology is the best? What kind of laser technology is suitable? From what perspective can I examine? What other indicators are used to quantify? Let's come close to the laser and unveil its mysterious veil.
There are many types of lasers, and they can be defined differently from different angles. Different from the medium of excitation, it can be roughly divided into solid lasers and gas lasers, which use different solids or gases as the medium, for example, the earliest laser uses ruby ​​as the medium. The mainstream laser currently used for laser cutting is a carbon dioxide laser, followed by a YAG laser. YAG laser has the characteristics of high photoelectric conversion efficiency and small volume, but its application is greatly limited due to its fast loss of energy pump source and high maintenance cost. The use of carbon dioxide lasers makes it easier to obtain the ideal laser mode and higher energy, coupled with stable performance and short downtime, which is widely used in the cutting of various materials.
In the carbon dioxide laser, the combination of the gas flow direction and the laser resonance output direction is divided into an axial flow and a cross flow laser. From the design point of view, the axial fast flow laser is relatively easy to obtain the ideal mode of the laser - TEM00 mode or TEM01 mode, so At present, the mainstream cutting machines in the world use axial fast flow carbon dioxide lasers. On this basis, we will explore the elements of laser-induced cutting.
One: laser mode. It is one of the most important indicators for measuring laser quality. Can be divided into single mode, basic mode and multimode. The fundamental mode is both TEM00 mode, and its index on the X and Y axes is 0, so it is an ideal dot. Its single-pulse three-dimensional figure is as follows:
The multimode is a non-zero index in the XY direction, and its beam quality is poor, and it is generally used only for welding and not for cutting.
Three: incentive mode. The carbon dioxide laser generates laser light by exciting carbon dioxide gas with an electrode, and can be classified into direct current excitation and radio frequency excitation according to the installation position of the metal electrode. The DC excitation has both the positive and negative electrodes in the laser tube, the electrode and the carbon dioxide gas are in direct contact, and the electrode has a long distance, and a high voltage (instantaneous voltage of up to 20 kV) must be used during operation, resulting in ablation loss of the electrode. Equipment maintenance frequency and cost are relatively high. The three major laser manufacturers in the world: TRUMPF (Germany), Germany ROFIN and the US PRC company mainly use the RF excitation mode. The metal electrode is outside the tube and does not contact with carbon dioxide gas, which protects the electrode very well.