There is currently a proverbial hype about laser welding. Especially manual laser welding. Everywhere you see videos of how best to work manually with a laser welding torch and how amazing the results are. Where does this great interest currently come from? In which field did laser welding originate in the first place and what do you have to pay attention to especially when welding manually with a laser welding torch?
With these and other questions, Igor Welder visited the Weld Lounge of Prof. Dr. Emil Schubert, alias WELDPROF®. With a doctorate of engineering in laser materials processing and a professorship in the field of "Production technology: thermal cutting, welding and surface treatment", he was able to directly answer questions due to his extensive knowledge..
Did you know that Einstein had already predicted the principle of a laser in 1919? The actual inventor of the laser was the American physicist Theodore Maiman, who was first to succeed in emitting a laser beam in 1960. However, the significance of this achievement could not even be guessed at the time. Therefore, it was to take a few more years before real applications were developed.
In the 1980s, laser technology made its debut in the automotive industry, where automated welding was already being carried out using laser as a tool. But why is it only now that the handheld laser is so present on the market?
Technology and economy
The first lasers were CO2 lasers, very complex in their construction and also expensive.
At that time, the rule was: 1 kW laser power = 100,000 Euros
Those who wanted to afford this, had to see great advantages in using lasers. In the further development of laser technology, fibre lasers have excelled, especially in sheet metal processing. These have 2 advantages:
- Fibre-optic cables are needed to steer the laser – instead of mirrors as with the CO2 laser – which is a relief.
- Due to the increasing number of units in production, costs could also be reduced.
Inexpensive handheld laser systems cost between 15,000 and approx. 25,000 Euros in Europe and the USA today. In China, systems are available for well under 10,000 Euros. The costs are thus still considerably higher than the well-known gas-shielded welding process, but the difference has become smaller.
Sheet thickness: Where does manual laser welding reach its limit?
The manual laser systems available on the market today weld with 500 W to 2 kW. With 2 kW power, you can achieve a welding depth of 2-4 mm. This is also the limit of what is possible for a welding specialist.
If we look at the focusability of a handheld laser, we can see that we cannot achieve the deep welding effect that is needed for thicker sheets. Of course, there are also fibre lasers with 4 kW or more, but manual laser welding is then no longer interesting with regard to the costs. Safety plays an important role in this power class.
Laser also has disadvantages in terms of gap bridgeability compared to classic gas-shielded welding. Components must be prepared and positioned very precisely. If a gap is too large, the laser shoots straight through. We don't want to imagine what that would mean in bridge construction, for example, where many people are doing a wide variety of work.
Danger from laser radiation is often misjudged
Highly reflective surfaces or attachment angles of the handheld laser pose the risk of unintentionally deflecting or scattering the laser beam. For this reason, suitable personal protective equipment such as a welder's protective suit, gloves, closed protective goggles especially for laser welding and a suitable welding helmet are absolutely mandatory. The videos circulating on the internet of welders without protective goggles and wearing shorts show gross negligence and must not be imitated under any circumstances! The power of a laser beam is usually only realised when it is already too late.
Welding fumes in the air?
Classic welding applications for laser welding are stainless steel or aluminum in thin sheets. Even though this looks like a clean job, you have to think about the extraction of welding fumes. The reason: as soon as metals are melted, fumes are produced. The highly dangerous chrome VI, which is released when welding chrome-nickel alloys, is invisible and odourless. A welding helmet with extraction already helps here. Surely it is an incentive for the development of a handheld laser welding head with integrated fume extraction.
The topic of manual laser welding raises many questions, which Igor Welder has taken from his community to the WELDPROF® and discussed. If you also want to know for whom manual laser welding is worthwhile, whether manual laser welding will replace TIG welding in the future or whether manual laser welding can make the profession of welder more attractive, you should watch the video on the topic:
Are you interested in other topics?
In general, every visitor to the WELDPROF® website can ask me specific questions via »Ask the WELDPROF®«. I am happy to answer them by e-mail or in one of my video formats. Interaction with interested parties from the world of welding and joining technology is expressly desired!
