How Fiber Laser Welding Works

Fiber laser welding is one of many laser processes and is used to join various materials together by creating a strong weld between them. While this is most commonly used for metals, it is a process that isn’t only limited to this type of material.

So how does it work?

This process is used to create a strong and permanent joint between two types of material. The laser being used will focus a beam of high-intensity light on a focused area. The aim of this process is to physically melt the two materials together to form a bond between them.

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Laser welding in action

One way to achieve this is to create a gap in a vapourised spot known as a “keyhole”, in which the joint of your secondary material can be inserted. The molten material that surrounds this joint flows around the cavity, and will eventually solidify to create a strong weld. This type of weld has a high depth to width ratio.

This is known as ‘keyhole welding’ or ‘deep penetration welding’. ‘Laser spot welding’ works in a similar way, except the hole that is created is much smaller. This is also called ‘micro welding’.

But there are also other types of laser welding too. Another popular type is conduction limited welding. This type does not aim to penetrate the surface layer of the material being used, instead it creates the weld at the surface level. This will leave a high width to depth ratio joint. The depths are usually less than around 2mm.

Here are some key points that separate the three processes listed above:

  • Spot welding – this is used for very fine spot welds, and most commonly for the welding of copper
  • Conduction welding – this is a stable process, and less sensitive to part fit-up variance
  • Keyhole welding – Much thicker depths of weld, for which a fiber laser is the most capable of achieving

There is also another term that you may come across in this process, known as dissimilar metal welding. This is the process of welding together two metals that are of a different nature. They could be the same metal in name, such as steel, but may possess different properties. Alternatively, they could be two entirely different metals, such as copper and aluminium. This has become an important process as many products nowadays, such as cars and batteries, are constructed from many different types of materials.

The advantages and benefits of this process

So, what are the benefits to fiber laser welding? As we have previously examined, there are five main benefits offered to the user:

  • Ultimate precision – you can achieve a high level of accuracy and control
  • Creating complicated joints – Fiber lasers can create complicated joints which other traditional welding techniques are unable to do
  • Low level of heat – This process uses a low heat application, which minimises any damage which could otherwise have been caused to the components or materials
  • Consistent welds – Consistent and repeatable welds can be made, and it is a much faster process than more traditional techniques
  • High strength welds – As well as consistent welds, you will find that these joints are also high in strength too

For a more in depth look at some of the advantages that fiber lasers have brought to the welding process, read our application insight here.

Reasons to use a fiber laser over other types of medium

There is more than one type of laser available on the market, and each has its own array of benefits. As we examined above, fiber lasers possess many advantages. But what makes these advantages stand out as compared to the other processes?

The main reason that fiber laser welding has begun to notice such increased use is that pretty much all industries around the world have moved towards lighter and stronger materials in their goods and products, including everything from automobiles to aerospace and electronics.

It is used in a variety of industries, such as the automotive sector

It is used in a variety of industries, such as the automotive sector

For example, more and more batteries and semi-conductors are being used, which heavily rely on aluminium and copper. These are reflective metals, and historically laser processes struggled to work with this metal as the beam was redirected back into the laser system. Our Fiber lasers are adapted to ensure customers using them to weld do not struggle with such a problem. The other benefit is the ease at which they can weld these dissimilar metals, a process we touched on above.

The other major reason to use this type of laser is the fact that industries have looked to become more efficient too, and with higher levels of production. This means that they want systems which not only work faster, but are more cost-effective too. All this, while sacrificing nothing in terms of quality and safety. Fiber lasers tick all of these boxes, as well as providing a longer service life and less maintenance times than the other types of laser.

Essentially, fiber lasers have helped to bring a new level of flexibility to many industries, allowing for new capabilities such as the ability to work with many metals that had previously been almost impossible.

Generally, gas lasers have drawbacks in terms of accuracy and heat output, while crystal lasers have drawbacks in terms of speed. Here you will find a good comparison of fiber lasers to crystal lasers for the welding process.


Thanks to the many benefits listed above, this process can be used for many applications, such as for the welding of clear plastics, other types of plastic, fuel cells and medical devices.

Laser welding is used on materials such as clear plastics

Laser welding is used on materials such as clear plastics

Here are some other detailed laser welding application insights from us here at SPI Lasers:

Looking for more information?

Do you have more questions about fiber laser welding? Or would you like more information on our range of fiber lasers? For this, or any other enquiries, please get in touch with us here, or register to receive regular updates.


Image credits: Michael Gaida and Meir Roth


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