Laser Welding Copper: Fiber Laser VS Green Laser VS Blue Laser

How Does Copper React with a Laser?

Nearly all metals on this earth can be welded; however, their behavior may differ. This difference mainly depends on the metal’s physical and chemical properties. You can think of their melting point, conductivity, and sometimes reflectivity. It actually depends on the metal that absorbs the energy.

Copper has two special properties that make the welding process challenging. One is reflectivity, and the other is conductivity. Its reflectivity is very high, approaching 90%, when infrared light (at 1064 nm) hits the surface. Thus, copper shows high reflectivity in the infrared wavelengths. But some of its light energy is absorbed by the copper, which then converts into heat. This heat can be used for welding.

Following years of research, it has been found that shorter-wavelength light is more suitable than infrared rays. Copper absorbs green and blue light more effectively. Using green light at 532 nm reduces the reflectivity of copper. You may compare it with a 1064 nm laser applied to steel. Both bring the same result.

Recent experiments have shown that blue lasers are more effective than green ones. Here, the wavelength is around 450 nm. Using a blue laser on copper enhances absorption by 60%. So, you can use a blue laser for both thermal conduction and deep penetration. It also offers high speed, 5 times better than infrared lasers.

Overview of Laser Types Used for Copper Welding

You can weld copper with different laser types. When using a single type of laser source, different types of metal parts react differently. As industries grew and new applications emerged, a single laser was no longer enough. Fiber, green, and blue lasers were developed to solve specific laser welding copper projects.

Laser Welding Copper with Fiber Lasers

Fiber lasers are among the most common lasers used in industry. It provides high power and excellent beam quality. However, copper only absorbs 5% of the laser’s energy, while reflecting the rest. It makes the welding process more difficult.

To start the welding process, copper needs high power density. This rapid heating will melt the copper. Once it melts, the absorption rate will increase. Often, this non-linear change makes the molten pool unstable. Such instability leads to spatter or porosity in weld joints.

Advantages

• Fiber lasers provide excellent beam quality for focusing. It increases the accuracy of the welding.
• This technology can provide the highest available power for copper welding.
• Fiber lasers are a relatively cost-effective option for general-purpose metal processing projects.

Limitations

• The fiber laser absorption rate is very low, around 5%.
• When working with fiber lasers, melt pool instability can lead to spatter and pores in the weld joints.
• Fiber lasers typically require high power density to initiate welding.

Laser Welding Copper with Green Lasers

Green lasers provide a shorter wavelength than fiber lasers. This shorter wavelength is efficient for copper to operate. It absorbs the energy well at room temperature. Thus, it allows easy initiation of the weld. As a result, the molten pool remains stable, and heat input stays well-controlled.

This practice helps resolve issues, such as spatter or porosity seen with IR lasers. Often, green lasers rely on IR lasers to produce green light via frequency doubling. This conversion limits the laser energy, making it suitable for thin copper welds.

Advantages

• Green lasers make welding initiation very easy.
• It offers a more stable metal pool than fiber lasers.
• Green laser welding copper needs low power.

Limitations

• Power output is often limited due to lower energy conversion efficiency.
• The initial cost is comparatively higher than that of infrared lasers.

Laser Welding Copper with Blue Lasers

Blue lasers have the shortest wavelength among these types. Copper absorbs blue light very efficiently. So, the absorption rate is relatively higher than that of the green and fiber lasers. And the welding starts smoothly even at low power.

In this process, stable energy coupling enables spatter-free welding. It is crucial for thin, high-quality electronic components and battery parts. Currently, blue lasers are best suited for thin copper materials. New diode technologies are increasing the power output for broader use.

Advantages

• Highest initial copper absorption
• Produces spatter-free welding reliably
• Ideal for thin copper and sensitive electronics items

Limitations

• Usually, the power output is relatively low for deep welding
• Slower welding speeds compared to IR welding on thicker materials

Fiber Laser VS Green Laser VS Blue Laser: Direct Comparison

All lasers are widely used for laser welding copper. Each has its unique benefits and limitations. Choosing the right one depends on balancing these benefits and limitations. The following four factors can be used to directly compare these lasers.

Absorption Efficiency in Copper

Absorption of energy shows how much energy the copper can absorb. Blue lasers have the highest energy absorption rate, almost 60%. It has the lowest energy waste rate due to its 35% reflectivity. Green lasers are almost as effective as a mid-range option. On the contrary, fiber lasers have the lowest efficiency. To overcome low-light coupling, they require higher power output.

Weld Stability

Laser micro-welding of copper and aluminum: blue lasers ensure uniform melt dynamics. High energy absorption helps to maintain constant coupling. This way, consistent welding delivers defect-free, repeatable results with high precision. Green lasers also provide steady weld pools. But fiber lasers often show an unstable state in the beginning. It results in defects and flaws in the welding.

Power Capability

Power capability is the maximum power a laser can deliver. Fiber lasers currently offer maximum power output. For this reason, it allows deeper penetration into thicker materials. Green lasers have low power, but modern lasers are in multi-kilowatt. They focus on precision work. In contrast, blue lasers can rapidly increase their power. However, their maximum power is generally lower for deepest welding.

Equipment Cost

Equipment cost includes the laser source and overall integration cost. Fiber lasers have the lowest cost per watt. It is more economical for higher-power needs. They are widely used in many industries. Blue and green lasers are initially costly. They are expensive due to their advanced and complex technology. But their efficiency reduces operational costs in the long run.

Which Laser Welding Copper is Ideal for Your Project?

Choosing the right laser also depends on how you plan to use it. Not all applications need the same power or precision. Some of your projects may require speed, while others may need more control. Looking at specific use cases typically makes it much easier to select the best laser welding copper solution.

Thick Copper Welding

For thicker copper welding, fiber lasers are more efficient. They provide high power and deeper penetration easily. Once the metal is melted, the rest of the process becomes easier for fiber lasers.

Thin Copper & Precision Welding

Blue lasers are an ideal option for thin and precise welding. It ensures stable welding over the entire process. And, green lasers are a strong alternative to blue lasers.

EV Battery & Busbar Welding

Green lasers are preferred for busbars due to their stability and depth of penetration. Manufacturers choose blue lasers for cell tab welding. It ensures high mechanical and electrical quality.

Cost-Sensitive Industrial Welding

Fiber lasers have the lowest cost per watt. Manufacturers usually prefer it for general-purpose copper work in industries. But high spattering may increase post-processing costs.

Summary

Laser welding copper is widely used in modern industries. It is widely common in the manufacturing of EV batteries, busbars, motors, and green energy systems. Naturally, copper is much challenging to weld with traditional methods. However, laser welding makes the process much faster and more precise.

Different lasers typically work differently with copper. Fiber lasers offer high power and reliability. On the other hand, green and blue lasers provide better absorption and stability.

If you are looking for a laser welding machine for copper, HantenCNC could be the right brand for your project. If you have any questions, feel free to contact us. Our professional team of experts is always happy to help.