What is Laser Welding & How Does It Work? 2023

We’ll go over the different types of laser welding, how they operate, their benefits, and their applications in this post.

A laser beam is used in the process of laser welding to fuse together metals or thermoplastics. Laser welding can produce narrow, deep welds between square-edged parts in thicker materials and high welding speeds of meters per minute in thin materials due to the concentrated heat source used.

There are various welding applications and techniques, such as MIG, TIG, Stick, and Flux-Cored. There are numerous books, articles, and other materials that cover these welding techniques. Today, we’ll go over the different types of laser welding, how they function, their advantages, and how they can be used.

What is Laser Welding?

To join several pieces together, laser welding uses a laser beam as a concentrated heat source. The laser welding process delivers a concentrated heat source and quickly forges a solid seam.

The automotive industry is where laser welding processes and applications are most prevalent because lasers increase productivity at a low cost when joining automotive parts, such as roof, door, or filter assemblies.

However, laser welding is also frequently used to join metals at a smaller scale in the jewelry and medical industries. Laser welding can be used to join any material with a high heat conductivity, whether it be for a car or a tiny piece of jewelry, or medical equipment. In high-volume manufacturing processes for the medical and automotive industries, laser welding is also frequently used.

How Does Laser Welding Technology Work?

An intensely concentrated beam of light is directed onto the gap between the materials to be joined during the laser welding process. The materials are melted at their seams and fused together by the strong laser beam. Laser welding in thin materials can be carried out quickly because it uses such a highly concentrated heat source. Laser welding can create deep, precise welds in thicker materials.

Two Types of Laser Welding

Two different kinds of laser beam welding exist, each with a different operating system tailored to a particular use case. Depending on the laser beam’s power density, the material will interact in a particular way.

Heat Conduction Welding

In this technique, the surface of the base materials are melted using a focused laser beam. An accurate and seamless weld seam is created when the joint solidifies. Welds created using the head conduction method do not generally need any additional finishing, the quality is great “out of the box”.

Only heat conduction can transfer energy into the weld zone. The welding depth is thereby constrained, making the procedure ideal for joining thin materials. When there are visible weld seams that must be aesthetically pleasing, heat conduction welding is frequently used.

There are two subcategories of heat conduction welding:

• Direct heating – the laser beam directly applies its power on the surface of the metals.
• Energy transmission – absorbing ink is applied to the joint, soaking up the energy that the laser beam applies.

Deep Penetration/Keyhole Welding

Deep, narrow welds with a uniform structure are produced when the process is run in keyhole welding (deep penetration) mode. Power densities of approximately 1 megawatt per square centimeter are used for metals. As a result, the metal is not only melted but also turned into steam, leaving a tiny cavity filled with steam.

The molten metal fills this vapour capillary, also known as a keyhole cavity, as the laser beam passes through the workpiece. The distortion and development of a heat-affected zone are minimized because keyhole welding is a high-speed process.

Laser Beam Welding Process

The basic idea behind laser beam welding is to apply heat to a joint between the surfaces of two metals by means of a laser with a high power density. At the joint, the material melts, and as it solidifies, it allows for metal fusion.

Typically, laser welding is done by welding robots that are guided by flexible optical fibers and are capable of applying a lot of energy precisely and quickly. As a result, the joint melts enough metal to produce narrow welds with little distortion. Although portable laser welding systems appear to be a great replacement for large industrial machines, the security of those welders is being called into question.

The welding process can be carried out in an atmosphere, but inert gas shielding is advised for more reactive materials to reduce the risk of contamination. Laser welding could be done in a vacuum, just like electron beam welding, but it is not regarded as being economically feasible. As a result, inert gas is supplied to the weld area by gas nozzles on laser welders.

There is often no need for additional filler material in laser welding applications. However, in order to produce satisfactory welds with some difficult materials and applications, filler material is needed. Filler material is added to improve the weld profile, lessen solidification cracking, improve the weld’s mechanical characteristics, and enable more exact joint fit-up. The filler material can be in the form of a powder or as filler wire, but since powders are typically more expensive for most materials, using wire feedstock is more common.

Butt welds, edge flange welds, filler lap welds, and overlap welds are the four most typical joint types used in laser welding.

Numerous metallic materials, such as titanium, low-carbon steel, stainless steel, aluminum, and others, can be laser-welded. It can also fuse less common materials like Kovar and combinations of metals that are thought to be difficult to weld, like copper and aluminum. Because of the high cooling rate, which often results in cracks, welding high-carbon steels is generally not advised.

Advantages of Laser Welding

Due to its adaptability, laser welding can be combined with arc welding to create hybrid laser arc welding. The final weld benefits from both laser and arc welding. Additionally, the weld has improved tolerance for joint fit-up and deep penetrating joints. Additionally, undesirable outcomes like internal porosity and cracking are decreased.

When compared to traditional welding methods, laser beam welding offers the following advantages:

Less Heat

The heat-affected zone (HAZ) is reduced in size by concentrating a laser beam on a small area. Consequently, compared to traditional welding, laser welding operations require low-temperature input.

Faster Processing Time

Although the initial investment is high, the procedure turns out to be more affordable than conventional welding. This is so that production levels can be raised and turnaround times shortened. Laser welding operates at a faster processing speed.

Lowers Risk of Thermal Distortion

Because there is little heat input during the process, there is less thermal stress. By only melting a small portion of the metal, the focused beam reduces internal stress and distortion brought on by heat on the workpiece.

High Precision

The laser beam can be directed and focused on a specific region. This enables precise component welding. Laser welding works best with delicate or thin metals due to its adjustable spot size.

Laser Welding Applications

There are numerous applications for laser welding because of its high precision, quick processing time, broad material tolerance, and reliable quality.

Some of the areas where laser welding can be applied include:

Automotive Industry

Laser welding is ideally suited for the automotive industry because it doesn’t require any tools and doesn’t require changing out heads.

Steel Construction

Laser technology is used in the steel construction industry because of its high productivity and production rates. The high speed, high tolerance processing of thick metal sheets is made possible by laser welding.

Shipbuilding

Laser welding is used in shipbuilding to produce control and drive screws, as well as rudders, with the high precision and desired tolerance. Ships can now travel at higher speeds while using less fuel.

Tool Construction

Because of its high precision, the laser welding system is appropriate for making tools. Making precise pressing, punching, and casting tools is now possible thanks to technology.

As a highly concentrated heat source, laser welding joins materials using a laser beam. The materials’ edges are heated and melted by the laser beam that is being used to create the joint. Laser welding has a wide range of applications and is frequently used for high precision welds due to its high precision, high welding speed, quicker processing time, wide material tolerance, and consistent quality.

Disadvantages of Laser Welding

• High initial investment
• Laser calibration and flawless workpiece assembly are necessary for tight tolerances.
• Aluminum and copper, which have high reflectivity and conductivity, can produce a finicky weld result when used with Co2 lasers.
• Rapid solidification could lead to porosity and brittleness.
• Laser optics are quite delicate and are easily broken.

Laser-Hybrid Welding

Combining the ideas of an electric arc and a laser beam is called laser hybrid welding. Together, the two simultaneously act in the same welding zone, enhancing one another and resulting in a special welding process. Although laser welding can be combined with almost any arc welding procedure, some stand out and are used more frequently.

There are three main types of laser-hybrid welding:

• MIG augmented welding (often synonymous with laser-hybrid welding)
• TIG augmented welding
• Plasma-arc augmented welding

The hybrid welding process offers arc welding-like weld cap profiles and the deep penetration that laser welding brings to the table. More control over the weld characteristics can be achieved through the use of protective shielding gases and other arc welding consumables than laser welding would permit on its own. Future large-scale pipe welding projects will increasingly use laser-hybrid welding, which is a process that is growing in popularity across a number of industries, including shipbuilding, railroad, automotive, and aerospace.

Summary: Laser Welding

Metals and thermoplastics are fused together by laser welding using a high-precision laser beam. Low thermal distortion is produced by the process’ accuracy and precision, making it ideal for welding delicate materials. High welding rates are made possible by the process’s frequent automation.

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