Laser welding as an engine of innovation

Apr 29, 2013

Lasers have long been able to do what traditional welding guns can. Nevertheless, many manufacturers did not dare employ the delicate technology in the raw environment of their assembly floors. At LASER 2013 (Hall C2, Booth 330), researchers will be demonstrating that lasers are robust enough to take over welding duties in fabrication.

Can lasers perform welds precisely and reliably in the midst of thundering machinery? The prototype of a new welder developed by an international team of researchers has now withstood the worst. At INTEGASA and ENSA, two companies in Spain that produce for heavy industry, the prototype proved itself precise and reliable under the difficult conditions of routine daily use.

"Manufacturers of heat exchangers were skeptical of laser anything until now," confirms Patrick Herwig from the Fraunhofer Institute for Material and Beam Technology IWS in Dresden. TIG-welding guns have traditionally been employed in assembly operations for welding thousands of tubes to the perforated tube sheets. This process, which is based on arc-welding technology, is very time-intensive however. The gun must be manually inserted into every hole and removed again after welding. As a result, the fabrication process is tedious, prolonged, and expensive. European manufacturers can hardly hold their ground today against competition from countries with low labor costs. Materials researchers, software specialists, production engineers and numerous users joined forces in the EU ORBITAL Project to jointly search for a cost-effective alternative. And found one.

Engineering that meets the most demanding requirements

Instead of conventional TIG-welding guns, a laser does the job – tube sheets and tubes are welded to one another rapidly, precisely and accurately. In seconds, the tube is circumferentially welded in place and the transporting the welding head can move on to the next hole. The welding head is designed so it anchors itself in the holes and is seated there so firmly than not even vibrations of the shop floor can disrupt the welding process. Precise guidance of the optical beam is handled by software-controlled mirrors that continuously direct it to the right location. Engineers and users from Italy, Spain, France, and Germany have been fine-tuning the process for two years. "The prototype we are exhibiting now at LASER 2013 facilitates the production of heat exchangers, and not just through its speed, but through its flexibility as well. It can even melt materials together that were considered difficult to weld until now," according to Herwig, who was responsible for designing and testing the welding head during the EU project.

It is exactly these exotic combinations of materials that are needed by manufacturers of heat exchangers. They have to withstand extreme conditions in actual use. Heat exchangers are used in the chemical industry, ship engines, and power plants to remove heat from high-temperature, aggressive solutions of liquids. The tubing these liquids are passed through must therefore be corrosion-resistant. However, the liquid in the tank outside the tubing that absorbs the heat is chemically inert. Cost-effective materials can be employed here. Where tank and tubing meet, differing materials must be joined. "Traditional welding techniques hit their limits here, whereas the job can be handled with the laser," says Herwig. The researchers are confident that laser can be implemented so effectively in production that European companies remain competitive internationally.

Explore further: Comfortable climate indoors with porous glass

add to favorites email to friend print save as pdf

Related Stories

Perfect welds for car bodies

May 11, 2011

Surface welding instead of penetration welding, allows a laser to produce a weld that is only visible on one side. But how do you control the laser power to prevent it burning a hole through the sheets of ...

Laser welding in the right light

Feb 02, 2011

Laser welding is on the advance, but it also has its limits: it has been impossible to fuse two transparent plastic components together -- up until now. German researchers have now succeeded in circumventing this hurdle -- ...

Recommended for you

Comfortable climate indoors with porous glass

11 hours ago

Proper humidity and temperature play a key role in indoor climate. In the future, establishing a comfortable indoor environment may rely on porous glass incorporated into plaster, as this regulates moisture ...

Crash-testing rivets

12 hours ago

Rivets have to reliably hold the chassis of an automobile together – even if there is a crash. Previously, it was difficult to predict with great precision how much load they could tolerate. A more advanced ...

Customized surface inspection

12 hours ago

The quality control of component surfaces is a complex undertaking. Researchers have engineered a high-precision modular inspection system that can be adapted on a customer-specific basis and integrated into ...

Sensors that improve rail transport safety

12 hours ago

A new kind of human-machine communication is to make it possible to detect damage to rail vehicles before it's too late and service trains only when they need it – all thanks to a cloud-supported, wireless ...

Tiny UAVs and hummingbirds are put to test

Jul 30, 2014

Hummingbirds in nature exhibit expert engineering skills, the only birds capable of sustained hovering. A team from the US, British Columbia, and the Netherlands have completed tests to learn more about the ...

User comments : 0