Introduction about laser welding technology

Laser welding is one of the important aspects of the application of laser material processing technology. The welding process is of heat conduction type, that is, the surface of the work piece is heated by laser radiation, and the surface heat diffuses to the interior through heat conduction. By controlling the width, energy, peak power and repetition frequency of the laser pulse, etc. parameters to melt the work piece to form a specific molten pool. Due to its unique advantages, it has been successfully used in the welding of micro and small parts. The emergence of high-power CO2 and high-power YAG lasers has opened up a new field of laser welding. The deep welding based on the pinhole effect has been obtained, and it has been widely used in industrial sectors such as machinery, automobiles, and steel.

Compared with other welding technologies, the main advantages of laser welding are: laser welding speed is fast, depth is large, and deformation is small. It can be welded at room temperature or under special conditions, and the welding equipment is simple. For example, when a laser passes through an electromagnetic field, the beam will not be deflected; the laser can be welded in both air and a certain gas environment, and can be welded through glass or materials that are transparent to the beam. After the laser is focused, the power density is high. When welding high-power devices, the aspect ratio can reach 5:1, and the Z height can reach 10:1. It can weld refractory materials such as titanium, quartz, etc., and can weld heterogeneous materials with good results. For example, copper and tantalum are welded together with two completely different materials, and the pass rate is almost 100%. Micro welding is also possible. After the laser beam is focused, a small spot can be obtained, and it can be precisely positioned. It can be applied to the assembly welding of micro and small components in mass automatic production, such as integrated circuit leads, watch hairsprings, and picture tube electron gun assembly. Laser welding not only has high production efficiency, but also has a small heat-affected zone and no pollution to the solder joints, which greatly improves the quality of welding.

It can weld hard-to-reach parts and perform non-contact long-distance welding with great flexibility. The use of optical fiber transmission technology in YAG laser technology has made laser welding technology more widely popularized and applied. The laser beam is easy to realize the beam splitting according to time and space, and it can perform multi-beam simultaneous processing and multi-station processing, which provides conditions for more precise welding.