SCX Special Projects created a highly complex crane automation system for an Aluminium Rolling Mill in Oman, designed to process around half a million tonnes of rolled aluminium product a year.
Molten aluminium brought in from the adjacent smelting plant is processed into coils and to facilitate this process, the rolling mill is equipped with 12 Street Cranes ranging from 7.5 tonnes to 80 tonnes SWL. Due to the complex distribution path options once the coils are rolled, the mill required a system capable of critical path analysis to organise and distribute the coils accurately through the most efficient route possible.
SCX Special Projects created a complex Crane Management System (CMS) to enable the two 25 tonne storage area cranes to automatically distribute hot coils into and out of storage and between a variety of different process lines in accordance with throughput and other plant processes.
Easily switched from manual to automatic, SCX’s Crane Management System (CMS) records information on type, time/date of any movement, as well as required onward processes, for each and every roll. It then organises predetermined process paths into the most efficient network possible; to get the coils to their destinations in the shortest time, to share the workload equally between the two cranes and to ensure they do not obstruct one another.
The cranes move the coils between the cooling area and an annealing furnace, between the cooling area and the general store, between the general store and tension line, into a slitting line or onto transfer cars to be removed from the mill, or back into the cold rolling area for adjustments. The CMS uses the data collected on each roll throughout its process path to safely and accurately move all the coils through the plant via the optimum possible route, as and when they are required.
The cranes accurately position the hot coils onto 45 individual stands in front of coil cooling air fans. The CMS assesses the coils’ cooling time and as the cranes come to collect them, sensors mounted on the grabs verify the temperature. Once below 70°C, the coils are automatically moved to one of 120 storage stands. Optical and pressure sensors determine whether the coils have been accurately seated in the grabs.
A Siemens SCALANCE wireless communication network links the cranes to the CMS and provides an approved E-stop, ensuring complete shutdown of the crane system in the event of emergency stop activation.
Because of the extreme operating environment which can be up to 60°C, air-con units keep the thermally insulated control cabinets at a suitable temperature.
