Laser welding is an important aspect of laser material processing technology application. In 1970s, it was mainly used for welding thin-walled materials and low-speed welding. The welding process belongs to heat conduction type, that is, laser radiation heats the surface of the workpiece, and the surface heat diffuses to the inside through heat conduction. By controlling laser pulse width, energy, peak power and repetition frequency, the workpiece is melted and a specific molten pool is formed. Because of its unique advantages, it has been successfully applied to precision welding of micro parts. The appearance of high-power CO2 and high-power YAG lasers has opened up a new field of laser welding. Deep penetration welding based on pinhole effect has been obtained and widely used in machinery, automobile, steel and other industrial fields.

Compared with other welding technologies, laser welding has the following advantages:

1, with high speed, large depth and small deformation.

2. It can weld refractory materials such as titanium and timely. It can weld anisotropic materials with good effect.

3. Micro-welding can be performed. After the laser beam is focused, a small light spot can be obtained and accurately positioned, which can be applied to the assembly and welding of small workpieces in mass automatic production.

4. Welding can be carried out at room temperature or under special conditions, and the welding equipment is simple. For example, when the laser passes through the electromagnetic field, the beam will not deviate; Laser can be welded in vacuum, air and a certain gas environment, and can be welded through glass or materials transparent to the light beam.

5. After laser focusing, the power density is high. When welding high-power devices, the depth-width ratio can reach 5: 1, and the highest can reach 10: 1.

6. The laser beam is easy to split beams according to time and space, and multiple beams can be processed at the same time and in multiple stations for more accurate welding.

7. It can weld inaccessible parts and realize non-contact long-distance welding with great flexibility. Especially in recent years, YAG laser processing technology has adopted optical fiber transmission technology, which makes laser welding technology more widely popularized and applied.