Welding robots keep quality high at Rustek

Complex welding tasks

The use of a wood pellet stove for heating has risen sharply in recent years, not only in Danish households but also throughout the rest of Europe. "The sharply growing demand caused us production problems, partly as a result of the relatively complex welding work on the internal steel parts of the stoves. "Many of the components are built up of several plate sections with complex welding details", explains CEO René Ramsdahl. "Each product easily involves about 15 to 20 metres of welding that has to be pressure-resistant and in some cases has as many as four different connections in each product. That calls for professional knowledge and the right processing strategy.

Experience gained with 'Mini cell'

"In 2012 we made a start with the robotised welding of small stain-less steel products on a Valk Welding 'Mini cell'. When the volume rose to over 2,000 units a year we took the step a year later to using a larger welding robot on an H-frame. That gave us the extra capac-ity we needed to weld the frames for the internal parts of the wood pellet stoves with the robot. This has also significantly improved the quality of the welding. "The welding robot produces a very precise weld that is the same for each product", says René Ramsdahl.

Third welding robot

The production volume has risen sharply in a period of four years. As well as automating the cutting and welding process, Rustek has also automated the bend processing with a robot on the press brake. "The increase of volume also made it necessary to extend the capacity of the welding department. The third welding robot runs on a track and moves back and forth between the two stations. This solution enabled us to work more flexible and also helped with the implemen-
tation of the larger products", says the CEO. The third welding robot system supplied by Valk Welding features the latest Panasonic TA-1900WG3 welding robot, which is de-signed especially for arc welding.

Software is the key

The investments in software and its optimisation form an important component of the annual budget. "Although it sometimes feels like a big black hole, the investments in software ultimately save us a lot of time. Each update takes the optimisation of the production process a step further", explains René Ramsdahl. That also applies to the welding department, where we program the welding robots in-creasingly smartly offline with the DTPS package from Valk Welding. This not only yields time savings in the form of shorter cycle times, but results in a longer working time for the welding robots. (DTPS upgrade cost less then 1,000.- Euro a year)

All in all, believes René Ramsdahl, without the automation efforts the company would not be able to exist in Denmark. The produc-tion processes are now automated from bending to welding and everything in between. That enables us to deliver a high quality product that is also cheaper and above all better than that of our competitors", he adds. www.rustek.dk

Wood pellet stoves

Wood pellet stoves are used mainly in Scandinavia to get rid of the excessive amount of wood dust. Wood dust can not be burnt on its own. But this is possible if it is turned into small stumps or pellets! The pellets create a pleasant flame pattern in a wood stove but also feature greater comfort and a higher energy output. They are burnt so efficiently that they barely leave any ash behind. This makes them more environmentally-friendly than ordinary firewood.