Application of Laser Welding Technology in Copper Welding
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Laser welding technology is gradually accepted by more and more people. This technology is also being applied to more and more industries. In the industrial field, laser welding technology plays its advantages well. But inevitably, people encounter all kinds of problems when using laser welding. Then let’s take a brief look at the difficulties of laser welding technology in the application of copper welding.
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At present, in industrial manufacturing, the consumption of non-ferrous metals, copper, ranks second. Its consumption is second only to aluminum. Copper is widely used in construction industry, electrical, machinery manufacturing and other industries. Copper has good electrical and thermal conductivity, excellent plasticity, and is easy to be processed by hot and cold pressing. In today’s society, with the continuous improvement of production demand, the application of red copper has gradually been expanded.
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Laser welding has the advantages of high energy density, less molten metal, narrow heat affected zone, high welding quality and high production efficiency. The application of laser welding technology to copper welding can effectively improve production efficiency, so it is gradually selected by more and more industries. However, due to the low absorptivity of high-reflection materials to fiber lasers, processing is also difficult. This also has more requirements for the laser light source.
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Problems that are prone to occur in copper welding:
- Difficulty fusion and variability
(1) Due to the relatively large thermal conductivity of red copper, the heat transfer speed is very fast during welding, and the overall heat affected zone of the welded part is also large, so it is difficult to fuse the materials together;
(2) Due to the large coefficient of linear expansion of red copper, when the welding is heated, improper clamping force of the clamp will cause the material to deform.
- Easy to appear stomata
Another important problem that occurs when copper is welded is porosity, especially when deep penetration welding is used. The generation of pores is mainly caused by two situations, one is the diffusive pores directly generated by the dissolution of hydrogen in copper, and the other is the reactive pores caused by the redox reaction.
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Although soldering copper is prone to these two problems, technicians have given corresponding solutions.
The absorption rate of red copper to infrared laser at room temperature is about 5%, and the absorption rate can reach about 20% after heating to the vicinity of the melting point. To achieve laser deep penetration welding of copper, it is necessary to increase the laser power density.
A high-power laser is used in conjunction with an oscillating welding head to agitate the molten pool and expand the keyhole during deep penetration welding, which is beneficial to gas overflow. This results in a more stable welding process with less spatter and fewer micro-porosity after welding.
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When the staff master some welding machine skills, the efficiency and effect of the welding machine will be improved accordingly.
Welding skills:
(1) The angle of the welding head is inclined during welding to prevent the laser from being damaged by long-term reflection.
(2) The power of the laser must reach the absorption value of copper to prevent the light from being reflected.
(3) The energy density ratio of the small core diameter of the laser can easily reach the absorption value of copper.
(4) Swing welding can improve the surface quality of welding.