When the Aluminium Laufen extrusion plant in Liesberg, Switzerland, replaced its old 16 MN press with a new 27-MN press in 2006, an integrated logistical concept for automatic long-goods transport was worked out, which also anticipated the 35-MN extrusion line installed in 2014. For this, as the company’s logistics partner H+H Herrmann + Hieber installed a complex and highly automated long-goods conveyor system with automatic cranes (process cranes), roller and chain conveyors, lifting platforms, vertical conveyors, section stacking machines and optimised packing work stations.
For the effective operation of an extrusion plant, nowadays the greatest possible automation of all the working steps – from the initial billets all the way to section dispatch – is decisive. In that respect the extrusion plant of Aluminium Laufen AG is noted for thorough planning and consistent automation of the in-plant material flows. The new 35-MN press has been integrated in the plant in such manner that even after the extension, the section production by all four presses moves fully automatically through the plant, all the way to the packing stations or the further processing facilities.
Besides conventional section production, Aluminium Laufen is now one of the leading producers of extruded pre-material for forging – a niche product but one which, spurred on by lightweight construction in the automobile industry, is continually becoming more important. In recent years the company has been able to continually increase its production of round bars. Whereas previously round bars were produced exclusively on the existing, older 25-MN press, the planning envisaged that the new press can be used as necessary, for both sections and round bars.
After the layer saws, whereas the profile sections are automatically stacked in racks, the preferred delivery format for round material is the hexagonal bundle. Since manual stacking entails both high costs and considerable physical strain, at the plant in Laufen steps have been taken in recent years to automate that difficult work step. Together with H+H Herrmann + Hieber a new stacker concept specially for hexagonal bundles was developed, which has proved its worth on the 25-MN press since 2012.
It was therefore logical to want to be able to carry our both types of stacking at the 35 MN press as well, namely both into racks and into hexagonal bundles. Since nothing is yet available on the market for this, a combined device had to be developed specially for this application. For the new combi-stacker, in order to be able to stack sections in racks or round material in hexagonal bundles in any desired sequence, the section stacking and round bar stacking functions were integrated in a mobile stacking gantry. With this arrangement conversion from one stacking mode to the other can be carried out simply and in a time-saving manner.
The full load-carriers – section racks or containers for round material – are moved by the clearing roller track to a position where they can be taken up by an automatic crane. The new, additional automatic crane can serve the preparation positions of the new ageing furnaces, the intermediate store accommodated on a platform and the automatic packing lines directly. In all, for the rack transport operations in the extrusion plant three automatic cranes (process cranes) have been installed.
The packing stations included in the material flow system are designed for maximum efficiency. The full racks are taken to the packing station by roller tracks, where they are automatically de-stacked. The layer of sections is placed on a feeder belt and moved to the two packers, ready for handling. All the required packing materials can be taken from dispensers as needed. The empty rack is then returned automatically back to the cycle.
The goods destined for further processing have to be transported to the top floor of the new shed, and taken away from there when finished. To be able to incorporate these transport operations as well in the automated system, three lifting devices for long-goods load-carriers have been provided.