Mechanical engineering specialist Rodomach (Deventer, Netherlands), working with a radiator manufacturer, approached industrial laser maker Rofin's subsidiary in Alblasserdam, Netherlands with a goal to convert its welding process from manual tungsten inert gas (TIG) welding to automated laser welding. In the process, the system had to be able to weld round pipes and models with angular pipes and special pipes, with 100% welding depth and able to pass the 25 bar pressure test. The last and most important requirement was a uniform, beautiful, and flawless seam weld that required no post-processing, so the final step—electro-polishing—could shine the stainless radiators to a mirror finish.
|The laser-welded towel radiator.|
First trials in Rofin's Hamburg Application Laboratory showed that the radiator's austenitic Cr-Ni-Steel AlSi 304 was easy to process, but the wide gap was too large—so a consistent, high-quality welding seam could not be guaranteed. The product requirements were determined together with Rodomach and suggestions for improvement were recommended, enabling automation and weldability with consistent high quality. So, instead of using traditional clamp tooling, the solution to this problem for the team was to use servo-controlled clamping with integrated cooling. This tooling method evenly clamps the part at all welding points, and the cooling prevents the joints from warping.
|System for welding different towel radiators.|
After conclusion of the trials, Rofin recommended using its FL 020 2kW fiber laser, which has a 300µm fiber and a 300mm focal length. Through use of a beam switch, one of these lasers can operate two robot welding stations to weld the two sides of the radiator alternately. With a 2m/min welding speed, pressure test results resisted 250 bar (far exceeding the 25 bar specification) and the system yielded constant high weld quality, surpassing the customer's expectations so much so that the company followed its initial order with an additional two systems.
For more information, please visit www.rodomach.nl and www.rofin.com.