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Recently, we have received feedback from users who want to see more basic science content. Yeah, well, we're on it right now. First, come with us to learn about laser welding from the ground up.
The "troika" of laser processing field is different
It is said that laser welding and laser cutting, laser marking together constitute the "troika" of laser processing technology, which has been widely used in the industrial field.
Laser welding and laser cutting and laser marking, the former development time is relatively short, its process difficulty is also greater than laser cutting and laser marking. Laser cutting and laser marking is the use of laser will be the surface structure of the material or the overall structure damage, and laser welding is the use of laser will be the structure of the material processing melting and rebuild. Compared with simple material structure destruction, material construction has higher requirements for laser and processing technology.
The specific comparison is as follows:
What is the difference between laser welding and traditional welding technology
Laser welding as a kind of modern welding technology, has deeply, high speed, small deformation, melting of the welding environment requirement is not high, big power density, is not affected by magnetic field, is not limited to conductive material, do not need to vacuum the working conditions and the welding process does not produce the advantage, such as X-ray is widely used in high precision manufacturing field, especially the new energy vehicles and power battery industry.
Compared with other welding processes, laser welding process has strong advantages in welding effect. The specific comparison is as follows:
But compared with other welding processes, the cost of complete equipment of laser welding automation is higher. It requires high precision of welding automation equipment and public joint equipment, which is difficult to operate manually. The welding material properties and fixture accuracy requirements are high.
What are the methods of laser welding
According to the different working principles and suitable for different processing scenarios, laser welding can be divided into heat conduction welding, deep fusion welding, composite welding, laser brazing and laser conduction welding, which are as follows:
In heat conduction welding, the surface is melted
Deep fusion welding creates a vapor filled hole, or pinhole effect
Laser brazing, using filled wire, active gas and protective gas laser welding
The classification by product combination is shown in the following figure. Butt welding requirements as far as possible seamless, generally less than 0.05mm. And the thinner the product, the more stringent the requirements; Penetration welding gap requires the upper and lower layers to fit firmly as far as possible, the thinner the upper material, the tighter the fit.
The core factor of laser welding
The core factors that determine the quality of laser welding are laser energy control and welding technology.
(1) Laser energy control
Because the material to be welded has different absorption rates of different wavelengths of laser (can vary from 5% to 50%), different laser choice, welding effect is completely different. In order to output uniform and stable welding laser beam to the weldment, it is necessary to have good consistency of laser output power or accurate control of laser output power, too low power will lead to insufficient welding fusion and affect welding quality, too high power or fluctuation will lead to spatter, porosity and other adverse effects. Therefore, the control of laser energy has become one of the key technologies of laser welding.
(2) Welding process technology
The effect of laser welding is related to dozens of factors, such as laser wavelength, power density, welding time, welding joint Angle, focal distance, laser absorption rate and cleaning degree of weldment, thickness and thermal conductivity of weldment, type of protective gas and flow rate, etc. Therefore, laser welding technology is also one of the key factors affecting the quality of welding, laser welding process technicians need to constantly explore and summarize, long time experiment accumulation can get a good welding effect.
