Laser as a welding tool was first used in the 60's; then it was ruby crystal lasers. Active industrial application of this technology started in the 80s: the power of laboratory CO2 lasers reached 25 kW, also Nd-YAG solid-state and disk lasers were used for welding.
In 1996, after 4 years of research and testing, the EuroLASER project was completed, which resulted in the approval of the commercial use of laser welding in the shipbuilding industry.
The use of laser welding machines in this industry reduces total costs by a factor of two and also has an impact on overall process time. For example, in the UK, at the Vosper Thornycroft shipyard, corvettes had been built a year faster precisely due to the introduction of laser welding and cutting into the production process. In Germany, similar technology in shipbuilding reduces the weight of ships by up to 30%.
Whereas in the past you needed huge laser units to work efficiently, now, a laser welding machine weighs about 45 kg and fits easily into a car luggage boot.
But these are not the only features of lasers. In this article we will explain in more detail the advantages of ytterbium laser welding, how it works, with which materials, where and how it is used, and what to look for when choosing a laser welding machine.
Advantages of laser welding and how it differs from traditional methods
The main advantages of laser welding machines are optimisation, speeding up, and making the process cheaper while reducing the weight of the final construction. For example, when laser welding was used for producing the Airbus A380, the weight of the aircraft had been reduced by 15% compared to the previous model A340 simply by using laser welded rivets instead of traditional riveting. Kerosene consumption per flight across the Atlantic has been reduced by 750kg, which is projected to save €9,000,000 over 25 years.
For the sake of clarity and specificity, we will cite laser welding machines from one of the world market leaders, Wattsan, as one of the best manufacturers to combine quality, advanced functionality, and affordability.
So, the advantages of laser welding include:
- Quality of welding. The physical and mechanical properties of the weld after laser welding are virtually identical to those of the original material. There are no defects such as: gas pockets, increased seam thickness, tarnishing, and drosses.
- Small heat-affected zone. The properties of laser radiation make it possible to weld metal without overheating or overburning it, minimizing warp distortions. This is especially true for thin-walled metal products.
- Speed. In some cases, it is up to 4 times faster than conventional welding methods. Average laser welding speed is of 1 to 10 m/min, with welding done in a single pass.
- No need for additional processing. In particular, there is no need for edge preparation or pre-treatment and post-treatment.
- Versatility. The laser welding machine is suitable for most metals and plastics. It can be quickly set up for new material. Laser welding is easy to integrate into the production process.
- Easy to master. Laser welding requires no in-depth knowledge or experience: even a beginner will quickly get into the process thanks to preset modes for different materials and settings for the laser beam trajectory for different tasks, which automatically imitate the movements of the electrode of traditional types of welding.
- No filler wire required. Structures with a gap of 0.3 mm or less can be welded without filler wire by a laser welding machine. Parts cut out on Wattsan laser metal cutting machines are especially well welded. Read more about laser metal cutters.
- Safety. Laser welding is much safer in comparison to traditional welding methods, as there is no release of molten metal or hazardous sparks at operation. It also makes working conditions more comfortable.
- Welding, cleaning, and cutting 3 in 1. Some laser welding machines, such as the Wattsan Laser Weld A1500 combine three functions: laser welding, cleaning, and cutting. This versatility makes it possible to simplify and speed up some production processes.
How laser welding works
A laser beam is generated in the source using pump diodes. Then, along the optical fiber, the beam passes in an active medium with a reflection close to 100% into a laser welding gun where a focusing lens is installed. After focusing, the beam reaches an extremely high power spectral density.
The maximum thickness of laser welding depends on the emitter's power. The minimum thickness is measured in tenths or even hundredths of a millimeter, depending on the material, and occurs with deliberate defocusing.
The welding gun has special electrically operated mirrors that can guide the laser beam to simulate the path of the weld. While traditional welding requires an experienced welder to do this, laser welding simply requires the gun to be guided evenly in a straight line..
Laser welding has several beam path modes:
- Upside down,
- Figure 8
- Straight Stepped
Each path type is used for specific tasks, whether it's for conventional welding, angle welding, riveting or other tasks.
Laser welding usually takes place in a gas environment, which not only creates a protective environment for welding, but also cools the nozzle and the protective lens. Nitrogen, helium, and argon are used for this purpose. Gas consumption in laser welding is much more economical than in traditional welding.
What can be done with a laser welding machine
Since laser welding is a rather expensive technology, it is most suitable for large applications such as chemical, nuclear, oil and gas, aerospace, military, medical, automotive, and shipbuilding industries.
The technology is gradually becoming more affordable, so it is being used in other, smaller, applications as well. However, laser welding is still an expensive solution for personal use.
Materials that can be welded with a laser welding machine:
- carbon steel,
- low-alloy steel,
- high-strength structural alloys,
- stainless steels,
- aluminium, copper, and brass alloys,
- dissimilar materials.
Types of welds to be performed:
- butt joint,
- edge joint,
- tee joint,
- lap joint,
- corner joint.
Criteria for choosing a laser welding machine
If you have decided to buy a laser welding, it is worth looking at the power of the emitter, the functionality and usability of the welding gun, the software options, the cooling method, and the compatibility with filler wire feeders.
Laser welding emitter and its power
The power determines the thickness the laser welding machine will be able to weld at a good quality. The specific welding thicknesses of the basic materials are shown in the table below.
Laser welding gun and its functions
The laser gun is lightweight, so it is easy to work for long periods without interruption in any position, even in hard-to-reach places.
Due to the dual-motor head, Wattsan laser welding guns are able to simulate special weld paths designed for different tasks.
The seam width is adjustable from 0.1 to 5 mm. The fibre length is 5 metres as standard, but can be made 10, 15 or 20 metres.
Some advanced models, such as the Laser Weld A1500, also allow the laser welding to be used as a laser cutter and laser cleaning machine.
Filler wire feeder
For welding without filler wire, the parts must fit together well. You can work without filler wire if the gap between the parts is no more than 0.3 mm.
Any wire feeder with a diameter of 0.8, 1.0, 1.2, and 1.6 mm is suitable for Wattsan welding machines, and the welding gun is also adapted for this.
Software, features, and range of settings for laser welding
The Wattsan laser welding machines have:
- user-friendly interface, with all settings displayed on the screen;
- 70 preset welding parameters for different metals and thicknesses;
- the possibility to save your own parameter settings for the most frequent tasks (you can change the power percentage, the frequency of the laser radiation from 50 to 30 000 Hz, the frequency of repetitions of the welding trajectory patterns, the load cycle, aka duty cycle, and other parameters)
- control of the weld configuration/shape
- the gas and laser beam are controlled via the welding gun
- seam width setting in the range of 0.5-5 mm
- programmed gas pressure control.
Cooling of laser welding
The most common cooling for laser welding machines is a chiller built into the housing with two circuits: one for cooling the emitter and the other for cooling the welding gun. The advantage of water cooling is that you can weld continuously around the clock.
Air cooling requires periodic work stoppages to normalise temperature, but practice shows that such interruptions are most often natural and unavoidable during the welding process.
The main advantage of air-cooled welding is its compactness. If you are planning to buy a laser welding machine, compare the water-cooled Wattsan Laser Weld 1000 with the air-cooled Wattsan Laser Weld A1500. The first model weighs 180 kg and has dimensions of 1120x550x1120 mm, while the second, the air-cooled model, weighs only 45 kg and has dimensions almost half as large: 650x300x621 mm.
Laser welding outperforms traditional methods of welding by a factor of 3 to 4, with a seam that is perfectly flat and smooth and has properties identical to the original material. That is why laser welding is the future of any industry where welding technology is needed.
If you want to buy a laser welding machine, it is important not only to choose the right machine, but also to contact a reliable company.
Virmer not only supplies laser welding machines to the EU, but also provides the following services:
- Virmer laser welding specialists will give you a detailed consultation and answer all your questions,
- Our managers conduct online demonstrations of the equipment and show the laser welding process on the materials you will be working with,
- Virmer engineers carry out start-up, integration of the laser welding machine into the production line, training, maintenance, and repair of laser welding machines.