Advantages of laser welding
Laser welding has many advantages, such as high depth width is deeper and narrower than the weld, and the weld is bright and beautiful.
Moreover, due to high power density, fast melting, low heat input to the workpiece, faster welding speed, small thermal deformation and small heat affected zone.
In addition, due to the high compactness of laser welding, the molten pool is constantly stirred and the gas is easy to come out, resulting in the formation of non porous penetration weld. The high cooling efficiency after welding is easy to refine the weld structure, and the weld has high strength, toughness and comprehensive properties.
In laser welding, the strong weld technology, high-temperature heat source and full absorption of non-metallic material components produce purification effect, reduce the content of impurities, change the size of inclusions and their distribution in the molten pool, do not use electrodes or filler wires in welding, and the melting zone is less damaged, so that the weld strength and toughness are at least equivalent to or even higher than the parent metal.
Laser welding is easy to operate. Due to the small focus spot, the weld can be positioned with high precision, and the beam is easy to transmit and operate.
It does not need to change the welding torch and nozzle frequently, which significantly reduces the shutdown auxiliary time, has high production efficiency, no light inertia, and can also stop and restart at high speed.
And it is a non-contact, atmospheric environment welding work. Since the energy comes from the laser, the workpiece has no physical contact, so no force is applied to the workpiece. In addition, the magnetic field has no effect on laser welding.
Moreover, due to the low average heat input and high machining accuracy, the reprocessing cost can be reduced.
In addition, the operation cost of laser welding is low, which can reduce the workpiece cost.
Similarly, it is easy to realize automation and can effectively manipulate the beam intensity and fine positioning.
Different ways of laser welding
According to the working mode of laser welding, it can be divided into:
Galvanometer welding uses the rapid scanning function of galvanometer to preset welding path, laser energy manipulation and other parameters on the computer. It has faster welding speed, high precision and good beam mode.
It belongs to a kind of fine welding.
Lap welding / splice welding
It is a welding method that extends two plates. The thickness and materials of plates can be the same or different.
It is widely used in the production of automobiles, container shells, metal frames and filing cabinets.
Laser spot welding
It uses the high-energy laser pulse generated by the laser to instantly heat the metal to form a short molten pool. The molten pool solidifies before the next pulse.
It has the advantages of faster speed, high efficiency, large height, small deformation and small heat affected zone. It is often used for jewelry, advertising word welding, etc.
It has two ways of penetration welding.
One is through heat conduction. The heat is transmitted to the lower contact surface through the upper materials to weld the two materials together.
The other is that the laser heats the lower material through the upper transparent material (such as plastic) to weld the upper and lower materials together.
It is also called wobbling welding.
In the welding work, the laser beam is swung along the track of the weld to improve the tolerance requirements of the weld and reduce the influence of pores in the welding.
In laser welding, fine manipulation of laser power is very important for the quality of weld, especially at the beginning and end of weld.
At different stages of melting, the absorptivity and reflectivity of metal to laser are quite different.
The experimental results show that good welding quality can be obtained by using segmented power control at the beginning and end of welding.
However, laser welding without segmented control is prone to obvious locomotive and tail effects at the beginning and end stages.