Laser welding can be divided into heat conduction welding and deep penetration welding. The heat of the former spreads to the inside of the workpiece through heat transfer, and the melting phenomenon only occurs on the surface of the weld seam. Welding of materials; the latter not only completely penetrates the material, but also vaporizes the material, forming a large amount of plasma. Due to the large heat, the keyhole phenomenon will appear at the front of the molten pool.
During the welding process, the metal is heated and cooled very quickly, and the temperature gradient around the molten pool is relatively large, making the joint strength often higher than that of the base material. Conversely, the joint plasticity is relatively low.
Using laser welding can obtain high-quality joint strength and a large aspect ratio, and the welding speed is relatively fast.
Because laser welding does not require a vacuum environment, remote control and automated production can be achieved through lenses and optical fibers.
The laser has a large power density, has good welding effect on difficult-to-weld materials such as titanium and quartz, and can weld materials with different properties.
After focusing, the laser beam can obtain a very small light spot, and can be accurately positioned. It can be used in the assembly welding of micro and small workpieces produced by large-scale automated production.
Due to the low absorption rate of solid materials for lasers, especially after the occurrence of plasma (plasma has an absorption effect on lasers), the conversion efficiency of laser welding is generally low (usually 5% to 30%).
Due to the small focus spot of laser welding, the equipment accuracy of the workpiece joint is high, and a small equipment deviation will produce a large processing error.
The development of high-power lasers and the development and application of new composite welding methods have improved the disadvantages of low conversion efficiency of laser welding. It is believed that laser welding will gradually replace traditional welding processes (such as arc welding and resistance welding) in the near future. Become the main method of industrial welding.
In addition, the laser is also an electromagnetic wave, but the laser wavelength used by the welding machine is very large, so there is no radiation hazard of short-wavelength light waves such as ultraviolet light.
There is no shortage of shortwaves for this induced radiation, and it has a small impact on the eyes and body. It is best to stay away from the solder joints.