Laser welding is one of the important aspects of the application of laser material processing technology. In the 1970s, it was mainly used for welding thin-walled materials and low-speed welding. The welding process is of thermal conductivity type, that is, the surface of the workpiece is heated by laser radiation, and the surface heat is diffused to the inside through thermal conduction. By controlling the width, energy, peak power and repetition frequency of the laser pulse With other parameters, the workpiece is melted to form a specific molten pool. Because of its unique advantages, it has been successfully applied to precision welding of micro and small parts. The emergence of high-power CO2 and high-power YAG lasers opened up a new field of laser welding. Deep penetration welding based on the pinhole effect has been widely used in machinery, automobiles, steel and other industrial fields.
Compared with other welding technologies, laser welding has the following advantages:
1. Fast speed, large depth and small deformation.
2. It can weld refractory materials such as titanium, quartz, etc., and can weld heterogeneous materials with good results.
3. Micro welding is possible. The laser beam can obtain a small spot after being focused, and can be accurately positioned, and can be used in the assembly welding of micro and small workpieces that are mass-produced automatically.
4. It can be welded at room temperature or under special conditions, and the welding equipment is simple. For example, when the laser passes through an electromagnetic field, the beam will not shift; the laser can be welded in vacuum, air and certain gas environments, and can be welded through glass or materials that are transparent to the beam.
5. After the laser is focused, the power density is high. When welding high-power devices, the aspect ratio can reach 5:1, and the highest can reach 10:1.
6. The laser beam is easy to realize the beam splitting according to time and space, and can perform multi-beam simultaneous processing and multi-station processing.
7. It can weld hard-to-access parts and perform non-contact long-distance welding, which has great flexibility. Especially in recent years, the use of optical fiber transmission technology in YAG laser processing technology has made laser welding technology more widely promoted and applied.