Powerful equipment needs strong foundations: The press shop in Győr has been constructed on a seamless slab of reinforced concrete 1.5 meters thick located eight meters below the surface of the ground. The slab is supported by 360 bored piles 15 meters long and 0.8 meters in diameter. The total floor space covers 26,000 square meters and has workplaces for up to 140 people.
The heart of the press shop is a large press line with the name Servo-PXL – the first of its kind at Audi. Compared with the predecessor generation, the equipment has a completely new design. The most important innovation is the 14 decentralized servo-motors comprising an electronically controlled single drive system, which replace the large, central drivetrain. They are not only significantly more efficient, but also allow the highly flexible adjustment of individual functions to suit the circumstances. The servo motors have a combined power of 5,460 kilowatts.
When the downward movement of the six slides of Servo-PXL is braked, the press recovers kinetic energy. Seven generator-storage units are installed in the basement of the press shop, whose rotors serve as flywheels. They save the energy for a few seconds and then return it to drive the machine. Another strength of the new press is the rapid changing of tools; which weigh up to 60 tons and are transported by cranes suspended below the hall’s ceiling. Tool changing is fully automated and takes just three minutes.
With dimensions of 93 meters long, 22 meters wide and 12 meters high, Servo-PXL is comparatively compact, because a new technology makes interim storage superfluous when the sheet metal is transported inside the press. With a total closing pressure of 8,100 tons, the new large press can carry out 17 strokes per minute. It can process 250 to 300 tons of sheet steel and aluminum to produce 22,000 to 24,000 parts every day.
Managing these enormous forces is difficult. In order to meet Audi’s high quality standards, highly qualified employees are required with keen eyes and a good tactile sense – to check the finished parts and to operate the equipment. Each tool has to be individually operated, and the sheet-metal plates frequently display deviations from the norm.
For this reason, the upstream strip-cutting machine examines the density of the sheet-metal plates, which it cuts from the large coils, with an electromagnetic process. In the press itself, some additional measuring techniques are already installed and yet more are planned for the future. They include so-called intelligent tools, which include sensors to monitor whether or not the sheet metal is optimally drawn into the press. If not, appropriate adjustments are made – on a scale of hundredths of millimeters for the precision required by Audi.
The material cycle in the Győr press shop is completely closed. Thanks to intelligent material use, offcuts are minimized right from the start – each window cut-out from a door for example is used to make two fuel-tank covers. All material left over is collected, pressed into cubes and taken away for recycling.