Trumpf laser technology supports laser scanner welding

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Trumpf laser technology is supporting laser scanner welding used in the doors of the new Audi A4, the first time the car maker has used the process.

Trumpf's technology includes its disk laser and also a new welding scanner head. It has so far been the only robot-guided solution to pass the tough qualification tests of the German automotive industry, and it’s already being used in series production. Since early 2007, the doors of the Audi A4 successor have been welded with a scanner system and Trumpf's 4 kW disk laser. Four manufacturing cells produce 1,800 doors per day using this technology. Conventional welding with solid-state lasers is an established process in automotive car body manufacturing. The development of this process led to robot-controlled laser scanner welding in which the movement of the bending arm robot can be combined with the highly dynamic positioning movements of a laser scanner. A significant challenge in this development was the availability of suitable laser sources with appropriate available beam quality. Lamp-pumped rod systems with a beam quality of 25 mm*mrad have already demonstrated their industrial suitability a thousand times in conventional laser welding applications. With values clearly exceeding 99 percent, these beam sources set new availability standards. However, a much higher beam quality is needed for laser scanner welding because the size of the processing space for a scanning optical system and possible the work area are dependent on beam quality. Since the potential of rod geometry has been exhausted as far as beam quality is concerned, only novel laser concepts can meet the requirements of improved beam quality. Trumpf's disk laser has a standard beam quality of 8 mm*mrad for the high power series, with a maximum power range of 8 kW. The advantages over conventional processes are improved productivity. The time that had been spent positioning the robot has been greatly reduced by the fast mirror movements of the scanner head, thus drastically reducing processing time. Compared to resistance spot welding in which an average of about 0.5 welds per second can be achieved, laser scanner welding typically can complete three to four welds per second.