Laser Welding Explained | Advantages and Disadvantages

Imagine fusing metal with the precision and speed of a laser beam, a technology once thought to belong only in science fiction. Many of the amazing creations made possible by technology appear as if you took them directly from a movie. For instance, laser welding is feasible and presently in use, while laser cutting has been around for a while. For many welders, this "high-tech" style of welding is new or unfamiliar. This article discusses the advantages and disadvantages of laser welding technology.

Let’s discuss the mechanics of laser welding, uncover its wide-ranging applications, and weigh its advantages and challenges.

What Is Laser Welding?

A laser beam creates a weld to fuse metals or thermoplastics during laser welding. Laser welding can generate narrow, deep welds between square-edged pieces in thicker materials and fast welding speeds of meters per minute in thin materials due to the concentrated heat source.

Conduction-limited welding and keyhole welding are fundamentally different ways laser welding works. The interaction between the laser beam and the welded material depends on the laser's power density when it hits the workpiece.

• Conduction Limited Welding – Conduction-limited welding occurs when the power density is less than 105W/cm2. The laser beam does not penetrate the material; it is absorbed into its surface. Because of this, conduction-constrained welds frequently have a large width-to-depth ratio.
• Keyhole Welding – Laser welding is more frequently carried out by adopting a keyhole mechanism and larger power densities. The material in the path of the laser beam melts and vaporizes when the laser beam is focused on a small enough area to provide a power density typically> 106-107 W/cm2 before substantial amounts of heat can be dissipated by conduction. The concentrated laser beam enters the workpiece and creates a "keyhole" cavity filled with metal vapor (which, in some cases, can even be ionized, forming a plasma).

The Process Of Laser Welding

A strong laser beam is used in laser welding to heat the joint. When the material resolidifies, the components are fused because it has melted on both sides of the junction. The bare minimum requirements are a laser, lenses to focus where you want, a mechanism to precisely move the beam over the joint, and a worktable to fit up and hold the components.

Using optics to "organize" or "refine" light waves into a focused, highly intense beam is rather difficult. Therefore, a laser's workings are outside this page's purview. There are numerous types of lasers with various powers. But the proper beam can rapidly raise the temperature of the metal on both sides of a joint.

The laser quickly applies the needed energy. You might need to fire the beam at the metal in pulses that last only a few milliseconds, depending on your laser and the nature of your workpieces. Or perhaps a continuous beam is ideal. You have a decent degree of flexibility over how the LBW system transfers heat to the pieces, but it depends on how much power is required.

Naturally, the molten metal will take a few seconds to cool and resolve. However, overall, the welding process is quick, making it a very efficient means of combining parts. Because of this, LBW is popular in applications requiring high welding speeds, such as manufacturing lines.

What Is The Purpose of Laser Welding?

Laser welding is primarily used to create clean, precise, and high-quality joints in various materials. Its main purpose is to produce seamless welds with minimal distortion. It is ideal for industries requiring accuracy and aesthetic finish, such as automotive, aerospace, medical devices, and jewelry manufacturing. Many locations that use laser welding strongly emphasize creating neat, attractive welds. These consist of the following:

• Automobile production.
• Making jewelry.
• Fluid and hydraulic control components.
• Narrow shell assemblies that are distorted.
• Foils.
• Fuel rails.
• Medical equipment
• Heat exchangers are made of stainless steel.
• Thin-gauge metal tubes, components, and boxes

Benefits of Laser Welding

When compared to other welding methods, laser welding provides the following benefits:

• It enables quick welding, deep welding, and small deformation.
• The welding apparatus is straightforward and can be used to weld at ambient temperature or under various circumstances. For instance, a laser beam does not change as it passes through an electromagnetic field. Also, laser welding can be done in the air, in a vacuum, and with certain gases. Even materials like glass that are transparent to the beam can be welded through.
• It successfully joins dissimilar materials and can weld refractory materials like titanium and quartz.
• In high-power systems, a depth-to-width ratio of up to 5:1 and even up to 10:1 is possible due to the high power density made possible by laser beam focusing.
• Laser welding may perform micro-welding by obtaining a tiny, precisely positioned spot. It is suitable for joining tiny and micron-sized components made in bulk. (The smallest spot allowed is 0.1mm)
• Laser welding is flexible since it can reach hard-to-reach areas and uses non-contact long-distance welding. Laser welding has become increasingly popular and practical for automatic integration due to the YAG laser processing industry's recent use of optical fiber transmission technology.
• The laser beam may quickly and easily achieve beam splitting according to time and location, allowing for multi-beam simultaneous and multi-station processing and creating the ideal environment for more precise welding.

Challenges and Limitations of Laser Welding

While laser welding offers speed and precision, it's important to understand the challenges it presents. By understanding these barriers, industries can make informed decisions about when and how to successfully implement this cutting-edge technology.

Below are the challenges and limitations of laser welding: 

• High precision required: Accurate alignment of the workpiece and beam is essential; even minor deviations can cause defects.
• Expensive equipment: The initial investment for laser welding systems is high. The laser and its associated technologies are expensive and require a sizable upfront investment.
• Material limitations: Reflective materials like copper and aluminum can be difficult to weld effectively due to the high reflectivity of the laser beam.
• Potential for heat-affected zones: Excessive heat can cause warping, distortion, or undesirable changes in material properties if not carefully controlled.
• Safety concerns: High-power lasers pose safety risks, requiring strict safety measures and protective gear.
• Limited use in some environments: In harsh environments with dust, moisture, or vibrations, maintaining precision can be challenging.

Conclusion

Laser welding stands out as a highly advanced and versatile technology, offering exceptional precision, speed, and quality in joining materials. While it presents certain challenges such as high costs and technical complexity, ongoing innovations continue to expand its accessibility and efficiency. Using this cutting-edge technology is a strategic move toward future-ready, high-precision fabrication solutions.