The packing of aluminium extrusions has always been one of the particularly labour-intensive operations in the extrusion plant. That this activity too can be designed in a rational way was demonstrated by H+H Herrmann +Hieber in the context of its modernisation projects in a number of extrusion plants.
If it can be assumed in unfavourable cases that the packing productivity amounts to around 250 kg per man-hour, then in a plant with two extrusion lines (3-shift operation) about 42 people have to be occupied with packing the sections. Cost factors in this way of working are the high proportions of transporting and auxiliary activities, and the time spent by the packing workers just waiting around.
To rationalise these sequences, there are from the outset two approaches: to reduce idle times and to speed up the actual packing activity. The first of these is achieved by mechanising the transport of the sections and packing materials, and the second by designing and mechanising the packing stations ergonomically.
- Transport mechanisation. The material transport tasks consist on the one hand of bringing in the goods to be packed and the packing materials, and on the other hand carrying away the packed sections and the empty racks. In these contexts solution approaches depend on the organisation and layout of the plant, and must therefore be planned individually (crane transport, roller tracks).
- Design of the packing stations. The design should make full use of every possible ergonomic option. Suitable work aids (lifting tables for the correct working height, dispensers for packing materials. etc.) boost the workers’ individual packing performance and at the same time make his work physically easier.
An example of this is the packing system installed as part of comprehensive modernisation measures at Aluminium Laufen AG in Liesberg, Switzerland. There, two mirror-image packing stations are supplied by a three-track roller conveyor. The full racks are brought into the packing station, automatically destacked and, when empty, placed on the empty rack return line.
The packing activities themselves still have to be carried out manually. To enable this as quickly, effectively and ergonomically as possible, the packing stations are equipped with every necessary work aid . Thus, the packing materials (paper, cardboard, foil, etc.) can be taken from dispensers directly adjacent to the packing position. The process of strapping is automated. The finished packs are moved onto a clearing roller track, where they are semi-automatically weighed and sent to the dispatch area.