Laser Welding (LBW) from Beams to Bonds: A Guide 2023-24

A unique and fascinating guide to “What is Laser Welding (LBW)?  “How Does It Work?”

Imagine a welding method combining the tiniest metal sheets with surgical precision and fusing materials as thick as a skyscraper’s support beam. Enter the mysterious realm of laser beam Welding (LBW). An orchestra of light and accuracy—it’s not your typical welding.

I’ll explore LBW’s unique world and uncover its secrets. Laser welding is an art that combines science and skill with light and heat. Every step, from laser beam focus to weld pools, is an engineering feat.

Learn about laser welding’s uses across sectors and how it has transformed production. Let’s explore the miracle of light-binding materials.”

How Laser Welding (LBW) Works

Getting to know the laser source

The laser source is the most critical part of LBW. This source can be a solid-state, fibre, or gas laser, sending out a very narrow, bright light beam. Which laser source to use varies depending on the job and the fused object.

Getting the laser beam to focus

Then, filters and mirrors focus the laser wave into a small energy point. This centred beam makes LBW so exact because it can be aimed very accurately at the area to be welded.

Interactions with Matter

When the focused laser beam hits the top of the object, it makes a spot with a lot of energy. This vital energy warms and melts the material quickly, making a weld pool. As the material cools, it hardens, making the weld joint solid and long-lasting.

 Classifications of laser welding

How the laser beam interacts with the material and the subsequent welding procedure determines the main categories of laser welding. Many significant laser forms of welding are often used.

Conduction mode Laser welding

• Conduction mode Laser welding is a technique that uses laser energy to join materials.
• In conduction-mode welding, the laser beam generates thermal energy at the interface of the materials undergoing fusion.
• The transfer of thermal energy occurs inside the material, resulting in the liquefaction and subsequent bonding of its surface.
• This particular technique often yields welds that are broad but need more depth.
• Conduction-mode welding is particularly well-suited for materials characterized by high heat conductivity, such as metallic substances.
• The topic of discussion pertains to the two modes of laser welding, namely keyhole mode and penetration mode.

Keyhole or Penetration Mode Laser Welding

• Keyhole-mode welding is a technique that entails the concentration of the laser beam to generate a cavity or puncture in the material, taking the form of a keyhole.
• The high level of energy results in the formation of a deep and slender weld that exhibits substantial penetration into the material.
• This particular mode is well-suited for thicker materials and can generate robust welds.
• It is often used for materials exhibiting poor thermal conductivity.
• The topic of discussion pertains to the process of laser spot welding.

Laser spot welding

• Laser spot welding is a technology characterized by its high level of focus, enabling the creation of tiny and exact welds.
• Acceptable welding applications are often seen in several sectors, such as electronics, jewellery, and microelectronics.
• This particular technique is well-suited to connect smaller or more fragile components.
• Laser seam welding is a technique used in industrial applications to combine two materials using a focused laser beam.

laser seam welding 

• Laser seam welding entails the controlled movement of a laser beam along the interface of two materials, forming a seamless weld.
• Airtight seams are often used in many applications, notably in the automotive and aerospace production sectors.
• Seam welding is renowned for its rapid and effective welding procedure.
• Pulsed laser welding is a technique that uses short bursts of laser energy to join materials together.

Pulsed laser welding

Pulsed laser welding is a technique that uses periodic laser pulses to achieve the fusion of materials.

This approach effectively mitigates heat input and mitigates the potential for material deformation.

This tool is well-suited for handling fragile materials and performing tasks requiring high accuracy.

Continuous wave (CW) laser welding

• Continuous wave (CW) laser welding is used in industrial applications to join materials using a continuously operating laser beam.
• In continuous wave (CW) laser welding, the laser beam is used continuously, ensuring a steady and uninterrupted heat supply.
• The high-speed welding mode is often used in applications requiring rapid welding, particularly in the automobile sector.

Laser hybrid welding

• Laser hybrid welding is a modern technique that combines laser energy with another welding process to improve welding performance and quality.
• Laser hybrid welding is a welding process that integrates laser welding with another welding technology, such as gas metal arc welding (GMAW) or tungsten inert gas (TIG) welding.
• The technology provides a harmonious equilibrium between velocity and the integrity of welds, making it applicable in many industrial contexts.
• The topic of discussion pertains to the process of laser micro welding.

Laser micro welding 

• Laser micro-welding is a widely used technique for achieving accurate and minuscule welds, often executed at the micro or nanoscale.
• This technology is used in several industries, such as microelectronics, medical device production, and other specialized sectors.
• Different types of laser welding possess distinct benefits and are selected according to the unique demands of the welding undertaking, encompassing factors such as material composition, thickness, accuracy, and velocity.

Types Of Lasers Used In Welding & Cutting

Lasers used for welding and cutting are mostly:

Gas lasers: Helium and nitrogen are used for gas lasers. Carbon dioxide lasers exist. A lasing medium excites the gas mixture using a low-current, high-voltage power source in these lasers. Pulsed or continuous operation.

Carbon dioxide lasers employ high-purity carbon dioxide, helium, and nitrogen. In dual-beam laser welding, CO2 lasers divide the beam into two equal-power beams.

Ruby and Nd: YAG solid-state lasers Use 1-micrometer wavelengths. They operate continuously or pulsed. Pulsed joints resembled spot welds but penetrated utterly. Pulses are 1–100 Joules. 1-to-10-millisecond pulses.

Diode lasers: utilized for hard-to-weld materials, hard-to-access places, and very tiny components. Reactive materials need inert gas shielding.

The Method of Laser Welding

Getting the Piece Ready

Before laser welding can start, the workpiece must be cleaned and set up very carefully. Any dirt or bumps on the surface can hurt the quality of the weld. Once the part is ready, it is safely clamped into place.

Setting up a laser welder

The laser source, aiming lenses, and a computer-controlled device that moves the laser beam make up the laser welding setup. Operators put the settings they want for welding into the system for the best results.

Delivery by Laser Beam

The focused laser beam is sent to the workpiece through mirrors and filters. With this method, the laser beam can be moved and placed differently.

Welding Standards

Key welding factors such as laser power, trip speed, and beam width are carefully controlled. These factors change based on the object being joined, its thickness, and the desired weld quality.

Advantages of Laser Welding

• LBW has the highest level of accuracy, making it perfect for situations where accuracy is the most important thing. The focused laser beam makes it possible to join small and complicated things.
• One of the best things about LBW is that it can make welds with very little heat. This makes the heat-affected zone smaller, lowering the risk of material warping and keeping the material’s qualities.
• LBW can weld various materials, from metals and alloys to plastics and ceramics. Because it can be used in many ways, it is helpful in many fields.
• The laser beam’s high energy density makes it possible to weld quickly. LBW can put things together faster than other types of welding.

Applications of Laser Welding

car Industry: 

LBW is used a lot in the car industry to ensure that parts like exhaust systems, engine parts, and body panels are accurately welded together.

Aerospace Business

In the aerospace industry, LBW is used to join important parts of planes and spaceships, where the strength and stability of the welds is most important.

Medical tools

In the medical field, LBW is used to make things like surgery tools and implants, which must be precise and clean.

Electronics Manufacturing: 

LBW is an integral part of making electronics because it makes it possible to assemble complicated parts with little heat stress.

Challenges in Laser Welding

• Not all materials can be welded with a laser. Some materials may not absorb the laser energy well or crack during the process.
• Laser welding tools can be expensive to buy and keep up, which keeps some companies from using them.

Future Trends in Laser Welding

• You need skilled operators to set up and run the laser welding process well, which adds to the overall cost.
• It is believed that the growth of fibre lasers will make LBW systems even more useful and affordable.
• Robotics can be added to laser welding processes to make them more automated and less reliant on human workers.
•  LBW is increasingly used in 3D printing, making it possible to make complicated, fully working parts.

Conclusion

Laser Beam Welding is a fantastic technology that has changed how welding and things are made. Its accuracy, speed, and ability to be used in different ways make it useful in many fields. As technology improves, we can expect laser welding to become even more enjoyable.

FAQs

Does laser welding work on all kinds of materials?

• Laser welding works well with many materials, but not all are suitable. Before choosing laser welding, ensuring the material suits it is essential.

Can a machine do laser welding?

• Yes, laser welding can be automated, mainly when robotic systems are used to make the process more precise and efficient.

How much do most tools for laser welding cost?

• The price of laser welding tools depends on its power, what it can do, and what brand it is. It can be anywhere from a few thousand to several million dollars.