To put it simply, laser technology is to use a polarizer to reflect the laser, and the generated beam will be concentrated in the focusing device, generating huge energy. If the focus is close to the workpiece, the workpiece will melt and evaporate in a few milliseconds, and this effect will be used in the welding process, that is, laser welding. At present, laser welding used in automobiles is mainly divided into two processes: laser brazing of ceilings and laser fusion welding of doors.
The laser welding process of automobile door refers to the laser welding of the door inner panel and the window frame reinforcement plate in the white body into the door inner panel assembly. The advantages of laser fusion welding of car doors are high welding speed and high welding accuracy.
The laser brazing process of the roof refers to the completion of the weld between the roof outer panel and the white body by laser brazing. The ceiling laser brazing system is mainly composed of robot, welding gun, laser source and welding wire feeding system. The laser generated by the laser source is transmitted to the welding gun through optical fiber, and the wire feeding of the wire feeder is controlled at the same time. The robot drives the welding gun and wire feeding tube to move, and the welding wire is melted by the focused laser, thus finishing the welding seam. Robots and laser sources are in one-to-one correspondence, and at the same time, they are standby for each other, which reduces the shutdown caused by laser source failure.
Generally speaking, the characteristics of laser welding are that the deformation of the workpiece to be welded is very small, there is almost no connection gap, and the welding depth ratio is high. For example, the weld width is very small, the connection gap is actually zero, and the welding quality is higher than that of traditional methods. Therefore, in some automobile top shells welded by laser, decorative strips are not used to cover the weld. Moreover, laser welding technology not only improves the appearance of the workpiece surface, but also reduces the amount of plate used. Because there is almost no deformation in the welded part of the parts, there is no need for post-weld heat treatment, and the rigidity of the car body is also improved.