The company Thöni Holding GmbH in Telfs, Austria, produces more than 45,000 tonnes per year of extruded aluminium profiles using four extrusion lines with extrusion loads of 12.5 MN, 16 MN, 25 MN and 32 MN. In its newly built extrusion and anodising plant, in collaboration with H+H Herrmann + Hieber (and with the Austrian company Böhler GmbH, Schwarzach supplying the control systems) the company has set up a complex, fully automated system of innovative transport solutions for long articles for its internal material flow.
When at the end of the 1990s Thöni wanted to increase production, that proved to be impossible in the existing production buildings for lack of space. For the third extrusion line with extrusion load 32/35 MN, in 1999 a new production building (christened the ‘Millennium Hall’ having regard to the time of its completion) was erected. In the new extrusion plant shed, with three naves, in 2004 the company’s fourth extrusion line with an extrusion load of 25 MN was also accommodated.
In the next extension step the surface treatment facility was enlarged. For this, in 2009 a new anodising plant was put up next to the central building complex near the entrance to the plant’s area. The provisional completion of the investment in 2015 involved building a further shed in which profile processing facilities are accommodated.
To make clear the transport requirements, below the arrangement of the buildings is outlined briefly:
- In the central building complex near the entrance to the plant’s area, besides the office wing and the Marketing department (‘Alu Welten’) the dispatch area and the 16-MN press are accommodated.
- Uphill and to the north of the central building complex is the newly built extrusion plant shed with the two presses, 25- and 32-MN respectively, including their run-outs, cooling beds, layer saws and stacking machines, as well as the heat treatment furnaces and the packing stations.
- Next to the central building complex, using the full width of the valley, the new anodising plant was put up.
- Following the direction of the valley, the processing shed, the last to begin operating, is adjacent to the Millennium Hall to its north.
In planning the material flow considerable height differences in the levels of the sheds (totalling 18 metres) had to be taken into account. A special transport solution also had to be found for the transfer between the extrusion plant and the further processing shed, because apart from the height difference the axes of the two sheds are directed at an obtuse angle to one another.
Material flow in the extrusion plant
The extrusion operation begins when the continuously cast bars between six and eight metres in length, stored in the yard of the factory, are taken up automatically and conveyed to the billet saw and after that to the billet heating furnace. For this, H+H developed a special system in which only the bundle of bars, unsorted, is deposited in front of the shed. All the following work steps are automated.
In the new extrusion shed the two extrusion lines are each located in the outer shed naves. The middle nave accommodates the production buffer store, the heat treatment furnaces and the packing station. In this area the racks are transported by two automatic cranes (AMCs), which are controlled in such manner that according to need they take loads to or remove them from the various areas of the logistical system. A novelty, and at the time of commissioning unique in Europe, was the arrangement of the two AMCs one above the other in this system solution.
For packing, a ‘smart’ system pallet developed together with the customer is used, on which stacking and strapping are carried out. The packs are transported to the dispatch area by the system pallets.
Transport from and to the extrusion plant
In the extrusion plant building the system pallets are first transported by the AMCs and by static conveyor technology to the so-termed ‘extrusion plant station’ and from there, over a distance of around 100 metres, to the vertical conveyor station. After being transported vertically through twelve metres, at the dispatch station the packs and system pallets are separated from one another. The ‘station areas’ have buffer conveyors on two levels for outgoing and incoming transport.
At the other end of the shed, the transfer to the processing shed, a height difference of seven metres has to be covered. In addition the axis of the new processing shed is not aligned with the extrusion plant. Finally, the works traffic between the two sheds also passes through.
For reasons of space the connecting stretch could only be designed as a two-way special link. The central part of the plant is the so-termed rack storage tower, with 13 storage bays in the area of the extrusion plant shed. At the opposite end of the conveyor, in the processing shed, is the terminal station with further buffer positions, which unload the automatic crane that works there. To boost performance, on this connecting stretch dual transport, i.e. two racks stacked one above the other, can be carried out.
Material flow in the processing shed
The new processing shed is divided into three naves. The machining stations are set up in the two outer naves; between them, in the middle nave of the shed, the stationary billet store and the terminal station for the connecting conveyor to the extrusion plant shed are located.
The material flow between the billet store and the lateral naves takes place by way of rack storage towers and two-way conveyors. Each of the two shed naves is (in the final, extended configuration) supplied by two storage towers. With the help of the storage towers the material flow between the AMCs and the work stations is decoupled. In addition, these stations also serve as intermediate buffers. A storage tower consists of a lifting unit, the storage bays (single or double depth, with conveyor stretches to the transfer point to the AMCs) and two input and output sections, by means of which in each case several machines in the further processing area are served. The maximum capacity of each storage tower is ten racks.
Material flow to and in the anodising plant
Goods to be anodised are transported into the anodising plant by means of a special, curved transfer carriage. Height differences, building orientations and space restrictions demand a special solution. The transfer carriage ends at a terminal station with buffer positions in the billet store of the anodising plant.
The innovative concept enables particularly space-saving and highly efficient implementation of all the transport requirements. This is achieved by virtue of the staggered arrangement, one above the other, of the functional areas: under the billet store, in the middle, a distribution trolley for connecting to the clamping stations and also, finally, an automatic crane. Thanks to the additional distribution trolley the transport movements are shared and the performance of the system is increased significantly. There is no need for stationary conveyor devices ahead of the clamping stations. The space gained in this way is used to extend the billet store by around 50 positions.