As the industries of new energy vehicles and electronics rapidly expand, the role of copper and copper alloys becomes increasingly vital in the manufacturing of motors, sensors, power generation and transmission equipment, and circuit boards. The connection needs for copper components are growing, driven by copper’s high reflectivity to most high-power industrial lasers and its high thermal conductivity during welding. These properties pose significant challenges, including difficulties in melting, significant deformation, and instability that can lead to porosity and spatter in welds. However, rapid advancements in laser welding technology are poised to overcome these challenges.
Here are the four main laser welding techniques currently leading the field for copper and its alloys:
1.Ring Mode Laser Welding
Application
Suitable for larger copper structures requiring deeper weld penetration.
Technological Advantages
This method uses a fiber optic to emit two coaxial laser beams, where the power of the center and outer ring beams can be independently adjusted. The center beam achieves deep penetration welding, while the outer ring minimizes the kinetic energy of escaping vapors and stabilizes the melt pool, reducing temperature gradients. This fiber laser welding machine not only achieves greater weld depths at high speeds but also effectively reduces spatter, resulting in smooth, aesthetically pleasing weld seams.
2.Single-mode Laser with Wobble Welding
Application
Ideal for thin copper sheets and small structures requiring shallow weld penetration.
Technological Advantages
A smaller fiber core diameter allows for higher power density, enabling instant keyhole coupling and formation. The wobble mode distributes energy more evenly, maintaining a stable keyhole even at relatively low linear welding speeds, effectively minimizing the porosity and spatter caused by unstable energy coupling and overheating.
3.Green Laser Welding
Application
Reduces heat input to minimize deformation due to welding.
Technological Advantages
Copper absorbs green laser light eight times more than it does near-infrared laser light. Even with the same depth of weld penetration, the heat input from a green laser is significantly lower than from near-infrared lasers, which reduces deformation of the product and minimizes damage to nearby components.
4.Nanosecond Laser Welding
Application
Micro-welding for precision components.
Technological Advantages
Nanosecond lasers feature high peak power and short pulse durations (nanosecond range), allowing precise control over heat input. The high repetition rate is ideal for welding metals, particularly suitable for highly reflective materials and dissimilar metals. This laser welding machine provides stable weld depths and effectively suppresses the formation of metal compounds in dissimilar metal welding.
Conclusion
Leveraging these advanced laser welding techniques, manufacturers can address the unique challenges presented by copper and its alloys, enhancing the quality, efficiency, and scope of their welding applications. As technology continues to evolve, these methods are expected to become even more refined, further expanding their applicability in various industrial sectors.