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In-tandem Welding

A pair of lightweight robots helps to limit manual welding tasks, making larger production runs more economical.

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Looking long-term, it was simply no longer cost-effective to manually process 500,000 to 600,000 parts per year in the assembly line’s welding and soldering processes.

As a classic parts and products supplier, Ferd. Wagner Profile constantly faces the challenge of having to produce products quickly and flexibly to meet its customers’ demands. Its main production focus lies in the manufacture of precision steel profiles for various industrial sectors as well as lifestyle products. As products change from season to season, production lines constantly have to be readjusted. During the process, however, methods for optimizing the company’s operations can come to light.

So was the case during the implementation of a long-term, major contract for the home furnishings industry when the company became aware that some aspects of its production system needed to be automated. Looking long-term, it was simply no longer cost-effective to manually process 500,000 to 600,000 parts per year in the assembly line’s welding and soldering processes.
The list of requirements for bringing in the automation solution, however, was lengthy. The automated device had to prepare and secure the unmachined parts without interference as well as ensure the parts were fed in for the welding stage. In addition, it was also important to ensure the parts were properly positioned for the subsequent soldering process.

Another challenge was to ensure the quality of the soldered connection. For parts destined for highly aesthetic, premium products, connections had to be flawless and could not contain any sign of discontinuity or leakage. The automation process also needed to replace the visual checking system previously used to monitor for defects. What is more, the employees at Ferd. Wagner were relatively inexperienced robot users, which meant the solution had to be easy to operate.

Robot tasks

Fortunately, Ferd. Wagner decided on two lightweight robots that are now responsible for preparing parts for welding and soldering from Danish robot manufacturer Universal Robots. The major contract that Ferd. Wagner was gearing up for involved processing a round metal component with a diameter of approximately 10 to 12 mm along with a component roughly 40 mm in length. Both components are pressure-sensitive and needed careful handling.

To manufacture the part, the two components are first carefully separated out using a separation system and placed in the correct position for feeding into the first robot. This robot is outfitted with a specially designed double gripper with tongs built to withstand high temperatures and that can grip parts securely.

Here, the robot picks up both pieces one after the other and places them inside an instrument attached to a tack welding machine. There, the two pieces are welded without any trace being left. The welding unit releases the connected part, before the robot picks it up and moves it to a park position where it gently places it into a fluid. At this point, the second robot picks up the part using a single gripper. When the first robot starts its cycle from the beginning, the second robot takes the part to a high-frequency station where it is soldered at a heat of 800° C so that it is permanently fused together.

The next stage is quality control, which is done using the Flexvision camera system made by Faude Automatisierungstechnik. The robot holds the part up to the camera in various positions so that the system can check all branch lines and seams. A lighting system ensures sufficient levels of luminosity. Compared to a visual check, the process ensures 100 percent objectivity. If the seam passes the test, the robot carefully places the part in the correct position within a sieve, making sure not to scratch it.

“It was essential to us that parts were handled carefully and gently,” Bernhard Eckert, production manager at Ferd. Wagner, says. “We had to ensure that the decorative surfaces, which are polished by hand in a final step, were at no risk of damage as this would result in the costly scrapping of parts. That is why, in addition to quality assurance, the maneuverability of the robots and the structure of the gripping tools played such a crucial role.”
Ferd. Wagner’s requirements were met with the robot duo and then some. The pair was designed to process around 160 parts per hour. They are used in two-shift intervals followed by a blind shift. At the end of the working day, the robots continue working on an unmanned shift until the material is exhausted. 

”This has allowed us to increase our productivity across the board. What is more, it has enabled us to reach our cost-stability targets,” Eckert says.

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Large-scale production has now been optimized by limiting manual welds, transferring this task to the Universal robots.

Implementation and training

As expected when implementing any new equipment, Ferd. Wagner contacted various providers before finally finding the right solution with system integrator Faude Automatisierungstechnik. Universal Robot’s six-axis lightweight robot weighs just 18 kg with a range of 85 cm. It can lift up to 5 kg. 

”Another key advantage of the robot is its intuitive user guidance system,” Dieter Faude, managing director of Faude Automatisierungstechnik, explains. “Individual pathways are shown to the robot using a touchpad before being saved. A one-day training session is all that is required to show technically adept employees, who have no experience with automation technology, how to use the programming system.”
These benefits are yet another reason why Ferd. Wagner chose the Universal Robots’ solution. It did not take long for the employees to adjust to the robotic applications in their plant.
“The robot guidance system is very intuitive – we were ready to take over by ourselves in no time at all,” Eckert says.

From an employee’s perspective, automation can be a concern when added to a facility. The worry is that the introduction of automation will make some positions no longer necessary. But, this was not the case at Ferd. Wagner. The employees previously in charge of the welding and soldering processes are still employed by the company. They are now mainly focusing on the processing of smaller batch quantities.

In the end, Ferd. Wagner – and its employees – have benefitted greatly from automation. More so, Ferd. Wagner now has agile manufacturing enabled, allowing the company to meet changing customer demands quickly and flexibly. At the same time, the company has increased quality control and productivity across the board all while achieving cost-stability targets.