New high-speed trimming shears for Elval

With a belt speed of up to 1,650 m/min, it is one of the fastest of its kind in the world.

The scope of supply for the new line at the Oinofyta/Greece plant includes the entire turnkey delivery from decoiler to transfer to packaging. The line lines strips made of alloys 2XXX to 5XXX, which are rolled in the new Sexto framework. It mainly processes uncoated strip for beverage cans, but is also designed for painted strip, which is conveyed through the system in a particularly surface-friendly manner. The belts are up to 2,100 mm wide. The maximum plant speed is up to 1,650 m/min.

The entire system works largely automatically: The plant control system receives specifications such as the width, thickness and alloy of the strip delivered from the coil warehouse from the plant's MES system and adjusts the individual parameters such as the immersion depth of the circular knives or the size of the cutting gap accordingly. The processes, which are optimized for all parts of the system, lead to very short coil-to-coil times. As a result, the new plant enables a throughput of more than 400,000 t/year.

For the preparation of the coil, an inline drum shear is arranged after the decoiler, which scoops head and foot scrap at a speed of up to 200 m/min. Compared to a start-stop solution, it saves time that would otherwise be needed for braking and accelerating again.

Due to the high precision and repeatability in the adjustment of the blades, the system achieves several times higher accuracy than required by DIN EN 485 during trimming.

A special feature is the intermediate trimming of the strip: If edge cracks are detected during rolling in the sexto stand, the edge strips on the coils in question can be separated in the trimming line, so that trouble-free rolling is then guaranteed again.

Due to the extraordinarily high system speed, the trimming scrap is extracted and wound up automatically. The hem strip wrapper is equipped with a wet scrubber that removes the spangles created during trimming.

The spray width of the electrostatic lubricator, developed in-house by GEORG, is automatically adjusted to the width of the respective belt, which avoids over-oiling at the edge and also reduces oil consumption. Oil droplets that come loose from the belt at the high plant speeds are extracted directly at several points. Despite the high belt speed, this results in extremely low oil emissions.

In the reel area, the empty sleeves are fed onto the mandrel by a manipulator and centered. The head of each tape is automatically glued to the sleeve. A pallet truck discharges the finished coils and transfers them to the packaging line.

GEORG has equipped the plant with several measuring and testing devices, such as an X-ray-based thickness measuring system, a hole detector and a surface inspection system.

The designers at GEORG have also attached great importance to energy efficiency: during trimming, the decoiler works as a generator, the energy is fed back into the system ... with a power consumption of a few hundred kW, this is a significant energy saving.

Detlef Neumann, Sales Manager Finishing Lines at GEORG, looks back on a successful project: "In the aluminium industry, there are only a handful of lines in the world that line at this high speed. We are all the more pleased that our customer accepted the system very quickly after trial operation and has been producing it with high efficiency ever since."