As we all know, in the list of non-ferrous metals, aluminum is located in the first place, copper second, second only to aluminum. Because copper itself has good electrical and thermal conductivity, excellent plasticity, easy to hot pressing and cold pressure processing, is widely used in the construction industry, electrical, machinery manufacturing and other industries.

Laser welding is an efficient and precise welding method which uses high energy density laser beam as heat source. Laser welding has the advantages of high energy density, less molten metal, small heat affected zone and superior welding quality. Because of the low absorption rate of the fiber laser with high reflection data, the processing difficulty is larger, which leads to more requirements on the laser source.

Problems prone to red copper welding:

(1) difficult to blend and variability: copper itself has a large thermal conductivity, so in welding, heat transmission speed will be very fast, the overall heat-affected zone range of welding parts is more, it is difficult to blend materials together; Secondly, because the copper linear expansion coefficient is very large, when welding heat, the clamping degree of the fixture is not very good control, easy to make the material deformation.

(2) prone to porosity: copper is prone to porosity in welding, especially in deep fusion welding. There are two reasons for the appearance of pores: one is the pores that occur directly when hydrogen is dissolved in copper, which is called dispersive pores; The other is the pore generated by REDOX, which is called reaction pore.

The solution:

In the room, the absorption rate of red copper to the infrared laser is 5%, and the absorption rate can reach about 20% after heating to the melting point. Therefore, in order to realize the laser deep fusion welding of red copper, it is necessary to improve the laser power density.

The high power laser is used to swing the welding head on the collocation, and the beam is used to stir the molten pool and expand the keyhole during the deep fusion welding, which is conducive to the gas overflow, and the welding is more firm, less splashing, and fewer micro-pores after welding.

Welding skills:

(1) When welding, the Angle of the welding joint is inclined to avoid long-term reflection damage to the laser.


 (2) The laser power must reach the absorption value of copper to avoid light reflection.


 (3) The energy density ratio of laser small core diameter can easily reach the absorption value of copper.

 (4) Swing welding can improve the surface quality of welding.