Double the wires, double the welding output
Rolling stock manufacturer more than doubles productivity when joining bogies
Mechanical engineers are subject to ever-increasing demands for productivity and efficiency coupled with fine product quality. Forged or cast steel parts often need to be joined. Stadler Rail Group experts use a robot welding system to weld bogie beams made of S 355 standard material with sheets thicker than 80mm. In the past, it took eight hours to weld a single solebar. Now, the TimeTwin Digital twin-wire system can weld two such solebars in just seven and a half hours.
In 2006, the experts at Stadler Winterthur decided to invest in increased productivity from their welding systems. They particularly targeted joining work on bogies, the supporting framework of rail vehicles. As alternatives they tested the laser and LaserHybrid processes and twin-wire MAG welding. "The laser variants were rejected for financial and technical reasons because the lower seam tolerances would have required expensive preliminary machining work on the long sections of the beams to be joined," explains Roland Mayer, head of the bogie centre. The relatively wide Laser Hybrid torch also obstructs access to certain joins. Twin-wire welding was therefore the clear choice. Winterthur experts chose the TransPuls Synergic 5000 system based on their excellent experience with Fronius systems.
In the meantime, the solution has proved itself in practice, operating on a two and a half shift basis. The robot welding system achieves more than twice the output. Productivity has increased significantly as welding output is higher and the robot operates at a faster speed. The seam tracking, which is now arc-based, has also improved the level of quality.
The TimeTwin Digital twin-wire system with two TransPuls Synergic 5000 Comfort power sources is primarily used to weld the longer seams of a bogie beam. Different seams are stored as jobs, and the robot calls up the right one when it needs it. To weld the root, the TimeTwin Digital control system switches to single-wire operation. The subsequent passes are then welded by both wires, primarily alternating between the two over the entire weld width.
The benefits in terms of efficiency are significant - checks during welding and manual rewelding are no longer required. This allows the system operator to concentrate on setting up the next beam in parallel. Reworking is no longer necessary as the TimeTwin Digital system prevents virtually all spatter. The test results for all seams are documented as proof of the high standard of joint quality.
Fronius International is an Austrian company with headquarters in Pettenbach, other sites in Wels, Thalheim and Sattledt, and production facilities in the Czech Republic and Ukraine. Fronius is active in the fields of battery charging systems, welding technology and solar electronics. The company employs 2,677 staff worldwide, 1,923 of whom are based in Austria. 93% of Fronius products are exported through its 14 sales subsidiaries, two agencies (Turkey/welding technology and China/solar electronics) and 130 sales partners around the world. 14.9% of the total turnover of 329 million Euro is re-invested (financial year 2009). With its outstanding products and services and 649 active patents, Fronius is world technology leader. 358 employees work in research and development.
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