The automobile industry is a production-oriented industry that requires a lot of processing and testing. It is also one of the industries where laser pointer technology is most widely used. Safety, comfort, energy saving and environmental protection have always been the themes of the world’s automobile industry development. Laser technology is used in modern automobile production. One of the main processing methods, its development is mainly centered on this theme and combined with the own characteristics of the profession. Due to the advantages of laser welding process, such as superiority, high efficiency, and good flexibility, as the concept of automobile lightweight and safety performance is increasingly enhanced, laser welding and cutting processes will receive more attention and be widely used in the automotive industry.
Laser welding process and application. Laser self-fusion welding, that is, the two or more parts of the welding are melted by themselves and finally cooled and condensed into a whole. This welding method does not need to add auxiliary flux or filler, and completely uses the material of the workpiece to be welded together.
When the power density of the laser spot irradiated on the surface of the workpiece reaches above 106W/cm2, the workpiece is rapidly heated under the irradiation of the laser, and its surface temperature rises to the boiling point in a very short time, causing the metal to melt and vaporize. A slender hole filled with metal vapor is formed in the metal. When the recoil pressure of the metal vapor balances with the surface tension and gravity of the liquid metal, the small hole no longer deepens, forming a deep and stable small hole. The small hole is surrounded by welding. In the molten pool, the small hole moves with the blue laser pointer. After the small hole is closed, a weld is formed to realize laser deep penetration welding.
In car body manufacturing, the use of laser welding technology can improve the flexibility of product design, reduce manufacturing costs, increase the rigidity of the car body, and increase the competitiveness of products. Laser welding has a faster welding speed, so the heat affected zone of the welded joint is smaller than other welding methods, and there is almost no welding distortion. This can greatly improve the structure and matching size of the body, the flatness and sealing effect of the door cover and the side wall, the matching and sealing of the windshield glass and the wind window, and the high-quality connection of the multilayer board to achieve a higher body strength .
Laser welding process and application. In addition, because modern car bodies mostly use galvanized steel or high-quality high-strength steel, if traditional spot welding technology is used, due to the three-layer plate and galvanizing, a larger welding current and welding pressure must be used, which will inevitably lead to welding The quality of the dots is reduced and the solder joints are severely deformed, resulting in a decrease in assembly quality. The only feasible option is to use intermediate frequency spot welding connection technology and laser engraver welding connection technology. As far as spot welding itself is concerned, the strength of the solder joints can be very high, but the parts without solder joints are still intermittently separated, and the overall strength of the car body is lower than the strength of the laser-welded joints welded together.
The discontinuity of spot welding and its own characteristics: such as the solder joints are easy to deform, especially when welding three-layer plate connections, galvanized plate connections and high-strength steel connections, the welding deformation is large, resulting in the flatness of the solder joints Reduce and produce gaps, and spot welding will cause the strength of the heat-affected zone of the base material around the welding point to decrease, and the fractured part when the vehicle is severely impacted is often there.