Fiber-Laser Welding: A Comprehensive Guide

Welding is an age-old process that uses localized heat to fuse together metals. In recent times, welders have been using fiber lasers to generate heat, which has revolutionized the manufacturing process.

Fiber-Laser Welding: A Comprehensive Guide

Read on to learn everything you need to know about fiber-laser cutting, fabrication welding, welding technology, types of welding, and more.

The Science Behind Fiber-Laser Welding 

Fiber lasers are solid-state welding lasers that use optical fibers made of silicate or phosphate glass to convert raw light from the laser diodes into laser beams. Pump laser-diodes convert electrical energy into light energy. Then, a coupler combines light from multiple diodes into a fiber-optic cable. 

Through the process of doping, rare-earth elements are added to these optical fibers to create laser beams of different wavelengths. Because fiber-laser cutting-machines can create many types of wavelengths, they're great for fabrication welding—which has many applications. 

Fiber lasers are typically low-maintenance, produce a smaller carbon footprint, and provide fast welding speeds without a large inventory of tools. This welding technology can save both time and money while achieving optimal welding and fabrication results.

If this sounds like the right technology for you, OMTech Laser offers a wide range of fiber-laser cutters fully customizable to your needs. Check out our selection or get a free consultation to help you find the best machine for your project.

Types of Fiber-Laser Welding Processes 

Fiber-laser cutters can work in different modes based on the power settings, beam focus, feed speed, and welding technique. Each mode has different characteristics and can produce a variety of welds. Here are some of the most popular types:

Conduction-Mode Welding 

In this mode, energy is transmitted to the object you're welding solely through heat conduction. This mode is ideal for spot welding and fusing thin materials because the weld depth is limited by the heat conductivity of the material. It usually ranges from tenths of a millimeter to one millimeter, with the welding width usually exceeding the depth.

This mode produces aesthetically-pleasing smooth or rounded welds that don’t require grinding or finishing. You can use conduction-mode welding in battery sealing and for corner welds on visible surfaces of electronic devices.

Keyhole-Mode Welding 

Keyhole mode causes vaporization, which results in the formation of a deep hole (keyhole) in the material to allow greater penetration of the laser beam. The large amount of energy this method delivers can maximize the weld depth, enabling more efficient joining with minimal heat distortion of the material.

The molten metal surrounding the keyhole then flows into the hole and seals the weld, making it incredibly strong. Hence, this mode is ideal for powerful equipment like turbine blades, tank beams, and spacecrafts.

Pulsed- and Continuous-Wave Welding 

Pulsed-wave lasers emit a series of short pulses, whereas continuous-wave lasers emit an uninterrupted beam. Continuous-wave lasers are great for welds requiring deep penetration, like high-carbon stainless-steel.

Pulsed-wave lasers can reach very high peak powers and are great for spot welding. Because the pulse duration is short, the heat level is low, so these lasers are suitable for use on heat-sensitive components, thin materials, and reflective metals like aluminum and copper.

Hybrid-Laser Welding

This mode combines both laser welding and traditional (arc) welding to fuse materials. It uses a powerful laser beam and compatible arc methods like metal inert gas (MIG), metal-active gas (MAG), or plasma together to enhance processing speed, penetration depth, tolerance to joint fit-up, and weld quality.

This dual technique can lower production costs, decrease power consumption, and ensure better control of materials—such as minimizing cracking. It's often used in shipbuilding, construction, transportation, and the production of machinery like cranes.

Fiber-Laser Welding Applications 

This metal fabrication process has many applications across industries. These include:

Automotive manufacturing, where fiber-laser welding is used for joining aluminum and mild steel to produce battery cells, engine parts, fuel injectors, solenoids, and air-conditioning units. 

The aerospace industry, where it can facilitate precision welding of titanium alloys to make turbine blades, frames, and fuselage sections. Fiber-laser welding can reduce aircraft weight by reducing the number of rivets.

Medical-device production, where it enables micro-welding for creating implants and other medical devices. The technology is efficient and durable.

Construction and heavy machinery, where it’s useful for high-strength welds, prototyping, and rapid manufacturing of window frames, plates, and pipes. This production process is tool-free, long-lasting, and cost-effective in the long run.

The Laser Welding Process 

Fiber-laser cutters use a high-energy laser beam to produce heat, which can create narrow but deep welds during the production process. A fiber cable carries the laser beam to the laser head, which then focuses the beam onto the welding field. The resultant heat causes the metal to rapidly melt and form a pool along the joining path of the welded surfaces. It then hardens upon cooling to form a strong and durable weld.

Filler metal is optional during this type of welding. This is a no-contact welding process, which doesn’t require specialized tools or advanced welding skills. Additionally, fiber Bragg gratings act as mirrors of varying reflectivity to strengthen and focus the beam onto the raw materials for fabrication welding. 

Other components of the setup include a cooling system to protect the machine components from heat damage caused by the laser beams and an operating system (hardware and software) to control machine parameters for metal cutting. Fiber lasers can be hand-held, attached to a robotic arm, or placed in workstations.

These machines also comprise many customized safeguards—like interlocks, warning lights, and shields—to protect operators from the harmful effects of the laser beam, which can cause skin and eye injuries. Furthermore, personnel must use protective gear like eyewear and gloves while using this machinery. It’s also important to keep the area ventilated to ensure fume dissipation and avoid placing any flammable materials in the vicinity.

Parameters and Process Optimization 

The laser welding process is affected by many factors, like laser power, energy density, beam focus, spot size, weld speed, travel path, and joint design. 

Low laser-power may cause insufficient fusion of the welding wire, whereas high laser-power can allow deeper penetration. The beam spot size is dependent on both the energy density and beam focus. The spot size, in turn, influences the weld's shape and energy dispersion in welding. 

Finally, it’s essential for machine setters to identify material properties like the melting point, thermal-expansion coefficient, conductivity, reflectivity, and absorption capacity, as these will determine all the other parameters suitable to create the perfect weld.

Quality Control and Inspection 

To obtain a real-time analysis of the weld quality and identify deviations, you can use a laser-weld monitoring system. This involves multiple features, like acoustic emissions, X-ray radiography, image processors, and optical signals. 

This system uses software to identify and flag patterns indicative of bad welds, thus automating quality inspection and fixing defects immediately. Additionally, this system can perform quality control checks before and after welds to enhance the accuracy of welding fabrication. 

Leverage OMTech Fiber Cutters for Better Results 

OMTech is a trusted name in the laser cutting machine industry. We leverage advanced technology with intuitive functioning to cater to your customized requirements.

If you’re wondering which fiber cutter is best suited for your welding trade, you can check out our website. Visit our demo room today to receive exclusive discounts and learn more about cutting operations.