What is laser welding, advantages and disadvantages

Laser welding

Laser welding is a welding method that uses a laser beam focused by a high-power coherent monochromatic photon stream as a heat source. This welding method usually includes continuous power laser welding and pulsed power laser welding. The advantage of laser welding is that it does not need to be carried out in a vacuum, but the disadvantage is that the penetration is not as strong as electron beam welding.
Laser welding can perform precise energy control, thereby achieving the welding of precision micro-devices. It has applications in many metals, especially solving the welding of some difficult-to-weld metals and dissimilar metals.
Laser generation: When a substance is stimulated, it produces a beam of light with exactly the same wavelength, frequency and direction.
Characteristics of laser: good monochromaticity, good directionality and high energy density. After being transmitted or focused by a reflector, the laser can obtain an energy beam with a diameter less than 0.01mm and a power density of up to 1013W/cm², which can be used as a heat source for welding, cutting, drilling, surface treatment, etc. The materials that produce lasers include solids, semiconductors, liquids, gases, etc. Among them, yttrium aluminum garnet (YAG) solid lasers and CO2 gas lasers are mainly used for industrial processing such as welding and cutting.

The main advantages of laser welding are:

(1) Lasers can be bent and transmitted through optical methods such as optical fibers and prisms. They are suitable for welding micro components and other parts that are difficult to reach by other welding methods. They can also be welded through transparent materials.

(2) High energy density, which enables high-speed welding, small heat-affected zone and welding deformation, and is particularly suitable for welding of heat-sensitive materials.

(3) Lasers are not affected by electromagnetic fields, do not generate X-rays, do not require vacuum protection, and can be used for welding large structures.

(4) Insulated conductors can be welded directly without stripping the insulation layer in advance; dissimilar materials with large differences in physical properties can also be welded.

The main disadvantages of laser welding are: the equipment is expensive, the energy conversion rate is low (5% to 20%), and the requirements for weld interface processing, assembly, positioning, etc. are very high. At present, it is mainly used for welding micro devices in the electronics and instrumentation industries, as well as welding silicon steel sheets, galvanized steel sheets, etc.