Laser welding is an effective welding process by utilizing the radiated energy of laser. Its working principle is that the laser active medium (such as the mixture of CO2 and other gases, YAG Yttrium Aluminum Garnet crystal, etc.) is excited in a specific way to oscillate back and forth in the resonant cavity, thus forming an stimulated radiated beam whose energy is absorbed by the workpiece when it contacts the workpiece.Welding can be performed when the temperature reaches the melting point of the material.

　 Laser welding can be divided into heat conduction welding and deep penetration welding. The heat of the former diffuses to the inside of the workpiece through heat transfer and only melts on the surface of the weld. The inside of the workpiece does not penetrate completely and no vaporization occurs basically. It is mainly used for welding low-speed thin-wall materials.The latter not only penetrates the material completely, but also vaporizes it to form a large number of plasma. Because of the high heat, keyhole will appear in the front of the molten pool.Deep penetration welding is the most widely used laser welding mode, which can penetrate the workpiece thoroughly and has high input energy and fast welding speed.

　　 Benefits of laser welding

　　①  High quality joint strength, large aspect ratio and fast welding speed can be obtained by laser welding.

　　② Because laser welding does not require a vacuum environment, remote control and automatic production can be achieved through lenses and optical fibers.

　　③  Laser has high power density, which can weld difficult-to-weld materials such as titanium and quartz, and can weld different performance materials.

　　④  Micro-welding is possible.The laser beam can be focused to obtain very small spot and can be positioned accurately. It can be applied in the assembly welding of small and small workpieces produced in large quantities by automation.

　　 Disadvantages of laser welding

　　①  Laser and welding system accessories are expensive, so the initial investment and maintenance cost is higher than that of traditional welding process, and the economic benefit is poor.

　　②  The conversion efficiency of laser welding is generally low (usually 5%-30%) due to the low absorption of laser by solid materials, especially after plasma appears (plasma absorbs laser).

　　③  Because the focus spot of laser welding is small, the equipment precision of workpiece joint is required to be high, and small equipment deviation will result in large machining error.

　　 Understanding Laser Welding Technology

　 Is laser welding harmful to people?

　　 The invisibility and energy of laser from welding machine is too high. Non-professional personnel should not contact the laser source, otherwise it is dangerous.In addition, laser also belongs to electromagnetic wave, but the laser wavelength used in welding machine is very large, so there is no radiation hazard of short wavelength light wave such as ultraviolet radiation.

　 Many gases will be produced during welding, but most of them are inert gases, which are not toxic. However, it depends on the different treatment of welding materials. It is best to take protective measures to reduce gas inhalation.

　 Lasers emitted by welders have almost no radiation hazards, but there will be ionizing and stimulated radiation during welding, preferably away from the welding area during welding.This induced radiation is not only short-wave, but also has a great effect on the eyes and body, preferably far away from the welds.In close working, we should try our best to take protective measures, such as wearing respiratory protection, radiation protection clothing and eyewear.