The most complex weld seam in thirty years of welding
Making aluminium bodies for luxury vehicles in small batches is a challenge. "Producing joint optics without compromising the high standard of quality is an absolute must. Neither pores nor subsequent filling is acceptable", explains Werner Karner, manager of the Fügezentrum Versuchsbau (Experimental Constructions Fusion Centre) at Magna Steyr. In this case, the weld seam joins the 1.1 mm thick sheets on the B-pillar with the sheets of the same thickness that make up the roof. Both are made from AlMgSi alloy 6014 and have to be joined using a fillet welded lap joint. This compensates for the accumulated error inherent in the manufacturing process caused by the difference in height between the B-pillar and the roof. "This is the most complex weld seam I've ever seen in my thirty-year career", explains welding expert Karner. The gap to be filled can be several millimetres wide, which makes bridging gaps without any material shrinkage extremely difficult. In the past, there was no suitable process available that was ready for inclusion in the production line at Magna. For production, this meant an unacceptable amount of reworking for each B-pillar. During their search for a more cost-effective solution, the managers at Magna Steyr tested the new arc alternating current process, CMT Advanced. Together with experts from developer and manufacturer Fronius, they have now come up with a suitable solution. The result following a few tests carried out under production conditions was the immediate integration of the system into series production using robots.
By allowing the user to select the polarity of the welding current, CMT Advanced opens up new ways of joining metal with even less heat input and a high deposition rate. The extremely stable arc increases the reliability of the process. A significant innovation is the fact that the change of polarity is carried out during the short-circuit phase. As there is no arc during the short-circuit, there are no negative effects such as arc cut-offs and the resulting process instabilities.
Fronius International GmbH
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.
Fronius International GmbH
Froniusplatz 1, A-4600 Wels
Tel. +43 / (0)7242 / 241 2590
Fax +43 / (0)7242 / 241 95 3940