Fibre lasers automate radiator welding

A Russian manufacturer of heated towel radiators sold to gyms and spas has replaced manual TIG welding in its production process with an automated laser welding system. The machine was developed by Dutch firm Rodomach, and incorporated fibre lasers from Rofin. The system is able to join round, angular and special pipes with a consistent and high quality weld.

The project arose when the radiator manufacturer approached Rodomach with the objective of replacing the TIG hand welding method currently used with an automated system. The manufacturer required a 100 per cent welding depth, a seam weld that required no post-processing, and the ability to join a variety of pipe shapes with a single system.

‘The end customer absolutely wanted laser welding and already had positive experiences with his two PWS tube welding systems from Rofin,’ said Robin Le Roy from the Dutch Rofin subsidiary in Alblasserdam.

Although the steel used in the radiators was easy to process, the gap to be welded was large enough that a high quality welding seam could not be achieved consistently. After confirming the product requirements with Rodomach, suggestions for improvement were recommended to the end customer to enable automation and weldability with consistent high quality. Throughout the project, however, part clamping and warp prevention were the main obstacles to be overcome before successful weld results could be achieved.

Through a collaborative effort, the development team at Rofin and Rodomach came up with a solution. Instead of using traditional clamp tooling, servo-controlled clamping with integrated cooling was used. Through this method, parts were clamped evenly at each welding point and the cooling prevented the joints from warping.

After conclusion of the trials, a 2kW Rofin fibre laser – Rofin FL 020 – with a 300µm fibre and a focal length of 300mm was recommended at Rofin's test centre in Hamburg. ‘With the high depth of field, the customer has a greater process tolerance and can therefore reduce scrap parts and improve productivity,’ stated Peter Kallage, manager of the applications lab in Hamburg.

In the final product, through the use of a beam switch, a laser is used to operate two robot welding stations which joins the two sides of the radiator alternately. ‘We have pooled the control of the system, the two robots and the laser on one terminal, to allow the customer simple operation of the system,’ reported Roel Doornebosch, manager at Rodomach.

With a welding speed of 2m/min and a consistent, high quality weld, the customer’s expectations were met and surpassed, so much so that the Russian manufacturer ordered an additional two systems.

‘The customer was aware of the complexity of the requirements right at the beginning of our collaboration and was eager to find out what we could offer him. It seems that we have surprised him, because he had not expected such a simple solution in the end,’ concluded Doornebosch.

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