Introduction

Copper, with its exceptional electrical and thermal conductivity, corrosion resistance, and ductility, is a cornerstone material used across various industries including automotive manufacturing, chemical processing, and telecommunications. The welding of copper and its alloys, critical for creating durable connections in these applications, has traditionally been challenged by the material’s high reflectivity to conventional near-infrared laser light sources. This often results in excessive spattering during the welding process, leading to surface roughness and other undesirable effects. However, the advent of Green lasers has revolutionized copper welding by mitigating these issues.

Understanding Formation Mechanism of Spatter

Spatter in laser welding occurs when the laser beam melts the copper surface, creating a molten pool. This pool heats until the metal boils and vaporizes, increasing the internal pressure and ejecting molten metal droplets. When using near-infrared laser welding machine, the initial low absorbance of copper at room temperature (around 5%) causes most of the energy to be reflected. As the temperature rises, absorbance improves but so does the likelihood of overheating and spattering due to the intense vapor pressures created within the molten pool.

Formation Mechanism of Spatter

Infrared laser welding of copper

The Shift to Green Laser Welding

Green light lasers offer a significant advancement in this context. Copper absorbs green light at a rate eight times greater than it does near-infrared light at room temperature. This higher initial absorbance allows for more efficient energy use, reducing the temperature overshoots that lead to spattering. As a result, green metal laser welder can achieve what is known as “zero-spatter” welding, a much sought-after quality in precision manufacturing processes.

Absorption rates of copper materials at room temperature for different wavelengths

Advantages Over Near-Infrared Lasers

1.Higher Absorption Rate

At room temperature, while copper’s absorbance of near-infrared light is only 5%, it leaps to 40% for green light, minimizing energy waste through reflection.

2.Reduced Spattering

The efficient energy absorption ensures that the metal does not reach the boiling point as rapidly or as often, substantially reducing spatter.

3.Improved Weld Quality

Green lasers produce smoother, more consistent welds under both pulsed and continuous modes, compared to their near-infrared counterparts.

Comparative Analysis

Pulsed Welding Outcomes

Green lasers demonstrate higher roundness and consistency in pulsed laser spot welding compared to near-infrared lasers.

Continuous Welding Performance

In continuous welding settings, green lasers ensure smoother, more uniform weld seams with minimal to no spatter compared to the often uneven results from near-infrared welding.

Applications of Green Laser Welding

The precision and efficiency of green laser welding make it ideal for applications requiring meticulous detail and durability. Some common uses include:

1.Heat Sinks

Ensuring efficient heat dissipation in electronic components.

2.Battery Busbars

Providing robust connections in battery assemblies.

3.Automotive Components

Manufacturing parts that require high reliability under thermal and electrical stresses.

4.Connectors

Creating stable, durable joints in electronic and electrical systems.

Conclusion

The adoption of green light lasers for welding copper represents a pivotal shift in manufacturing technologies, particularly for industries where precision and efficiency are paramount. This technology not only improves the quality of welds but also contributes to more sustainable manufacturing practices by reducing waste and increasing throughput. As industries continue to innovate, green laser welding stands out as a transformative tool in the metallurgical and manufacturing landscapes.