What Are The Advantages Of Laser Welding Over Traditional Welding?

Laser welding is a fusion welding method that uses high-energy density laser beam as the heat sources to melt metal to form welded joints.

Using laser welding, not only the productivity is higher than that of traditional welding methods, but also the welding quality is significantly improved.

The thickness of workpieces that can be welded by laser welding can range from several microns to 50mm.

Compared with other welding methods, laser welding has the following advantages:

1) There is no mechanical contact between the welding device and the workpiece to be welded.

This can not only avoid the deformation of weldment during hot pressing welding, but also avoid the pollution to weld metal during resistance welding, argon arc welding and gas welding, which is very important for the welding of vacuum instrument elements.

2) Weld inaccessible parts.

The laser can reflect and transmit and can travel a considerable distance in space with little attenuation. It can be used for welding at long distances or some inaccessible parts.

The laser can be guided to inaccessible parts for welding by means of deflection prism or optical fiber, which has great flexibility.

In addition, the laser can also be welded through the wall of transparent materials, such as the welding of electrodes in vacuum tubes.

3) High energy density, suitable for high-speed machining.

The focused laser has a high energy density. The welding can be carried out by deep penetration and the welding speed is high.

Due to the high energy density and small heating range (diameter < 1mm), the heating and cooling speed is large, the heat-affected zone is very small, and the residual stress and deformation of laser welding are small.

It can avoid “thermal damage” and can process precision parts and thermal sensitive materials.

It has a broad development prospect in the processing of electronic industry and instrument industry.

See table 6-5 for the comparison of power density between laser and other welding heat sources.

4) It can be used to weld materials that are difficult to be welded by general welding methods, such as high melting point metals, and even non-metallic materials, such as ceramics, plexiglass, etc.

The insulated conductor can be directly welded.

The conductor with insulation (such as polyurethane formate) can be directly welded to the wire column by laser welding, while the insulation layer needs to be stripped first by the ordinary welding method.

Table 6-5 comparison of power density between laser and other welding heat sources

Heat source

Power density/(W/m2

Laser

Pulse continuous

1012~1017

109~1013

Electron beam

Pulse continuous

1013

1010-1013

Electric arc

1.5×108

Oxyhydrogen flame

3×107

5) Welding of dissimilar metals.

The laser can weld metals with very different physical properties such as steel and aluminum, and the effect is good.

The depth width ratio of laser welding can reach 10 ∶ 1, and micro parts can be welded.

Compared with electron beam welding, laser welding has neither vacuum system nor the risk of generating X-rays in the air like electron beam.

One laser can be used for different work of multiple worktables. It can be used not only for welding, but also for cutting, alloying and heat treatment.

Because laser welding has the above advantages, on the one hand, laser welding is widely used in some micro parts.

At the same time, with the emergence of high-power laser, laser welding has also been widely used in automobile, steel, shipbuilding, aviation and other industries.

The disadvantages of laser welding are: it is difficult to weld some metals with high reflectivity; The one-time investment of equipment (especially high-power CW laser) is larger than that of other welding methods;

The requirements for processing, assembly and positioning of weldments are very high.

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