Laser Beam Welding Explained

Laser beam welding (LBW) is a precise and efficient method used to join materials through the use of a laser beam. It is known for its accuracy, speed, and ability to work on small, delicate components, making it ideal for industries like electronics, batteries, automotive, and aerospace. 

In this article, we’ll break down how laser welding works, explore its advantages and disadvantages, and clarify the difference between laser beam welding and laser welding.

Table of Contents

• What is Laser Beam Welding?
• How Does Laser Welding Work?
• What are the Advantages and Disadvantages of Laser Welding?
  • Advantages of Laser Welding
  • Disadvantages of Laser Welding
• Which Term is Correct: Laser Welding or Laser Beam Welding?

What is Laser Beam Welding?

Laser beam welding is a precise and highly controlled welding process that uses a concentrated beam of laser light to fuse metals. It can also be used to fuse other materials that can melt and resolidify, such as ceramics and plastics. 

Laser beam welding is ideal for thin or delicate components that require a high level of control and precision. It is used in the battery, automotive, and aerospace industries.

How Does Laser Welding Work?

Laser welding uses the energy contained in a focused beam of light to melt and fuse surfaces.

Here’s how it works step by step:

1. The laser generates a highly focused beam of light using a range of optical and electrical components. You can find an example of how laser beams are generated in fiber lasers here.
2. The laser beam is directed and moved onto the surface using motion axis, robots or fast-rotating mirrors (galvo mirrors).
3. The energy from the laser light is absorbed by the surface. Part of it is also reflected depending on the material’s reflectivity to the selected laser type/wavelenth.
4. The energy absorbed by the surface is converted into heat.
5. The localized surface heats up very quickly, creating a small melt pool. There is minimal heat distortion in surrounding areas.
6. The molten material resolidifies in a few milliseconds, leaving almost no time for contaminants like hydrogen to penetrate the welds.

What are the Advantages and Disadvantages of Laser Welding?

Advantages of Laser Welding

1. Small Heat Affected Zone (HAZ)

The heat-affected zone is the area of the welded piece that has not been melted but that has undergone changes in physical and chemical properties due to high temperatures. 

With laser welding, the heat input is lower because the process is fast and focused. This reduces the size of the heat affected zone and minimizes the potential negative effects on the material’s properties.

2. Good Mechanical Properties

Because laser welding offers better control over the heat input, parts are less distorted and warped by heat. As a result, they maintain better mechanical properties.

3. Ability to Weld Small Components

Laser welding is a precise process that makes use of a highly focused beam of light whose diameter is typically from a few tenths to a few hundred microns. This makes it ideal to weld small components like electronics and battery tabs.

4. Fast Process

Laser welding can be powered by high-power lasers of several thousands of watts. They can be as fast as needed to meet demanding production requirements.

5. Easy to Automate

Modern laser welding systems can operate 24/7 with very little maintenance. This makes them ideal for automated production lines requiring high throughput. They also have access to remote laser heads to perform welding from a distance.

6. High-Quality Welds

Due to the high control over the heat input, laser welded surfaces absorb heat and cool down faster than with traditional methods. This leaves minimal time for contaminants like hydrogen to penetrate the welds and cause mechanical damage.

Disadvantages of Laser Welding

1. Laser Safety Needs to be Ensured

Safety is important with all welding methods. With laser welding, the laser beam and its reflections need to be enclosed.

2. Safety is Complicated with Large Parts 

Larger parts like ships and fuselage sections are complicated to weld safely because larger areas are more difficult to enclose. Engineers often need to come up with new ways to enclose the laser beam.

3. High Initial Investment

Fiber lasers have been getting more affordable each year since 2006, but they are still more expensive than traditional welding technologies.

4. Reflective Materials

Laser welding works because the surface absorbs energy from the laser beam. With some materials like copper, a large part of certain laser beam is reflected, which makes it challenging for laser experts to optimize the process.

Which Term is Correct: Laser Welding or Laser Beam Welding?

Laser beam welding is the same thing as laser welding. It’s just a fancier term that has stuck for historical reasons. Both terms are correct, but “laser welding” is more common.

Let’s look at the historical context to understand this better.

The Origin of the Words

If you look at the following Ngram, the terms laser welding and laser beam welding both started appearing in the 1960s when there was a lot of interest and research going on in laser welding applications. You can see a trend showing that the term laser welding was already more popular.

The same thing happened with the terms laser cutting and laser beam cutting. Both terms started to be used at the same time, but “laser cutting” has always been more popular.

Dropping the Beam

There’s an interesting shift if you look at other laser processes. No one uses the word “beam” with laser marking, laser cleaning, laser texturing, and many other laser processes.

Why is that?

Laser cutting and laser welding were the first laser processes to be developed. At that time, the technical language was new and still being developed.

As other processes like laser marking and laser cleaning were developed, the word beam was dropped. This shows a general agreement that the word was not needed, or that it didn’t add much clarity or value.

Nowadays

Nowadays, more people use “laser welding” than “laser beam welding”. While “laser beam welding” may still appear in formal contexts, it doesn't make the term more precise or formal. It’s simply an extra word that has persisted for historical reasons.

Laser Welding Machines for Batteries

Laserax manufactures laser welding machines for batteries. These machines are essential to ensure EV battery production keeps up in pace and quality. 

If you want to know how these machines work, watch the following video:

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