How is it done?
The original rectangular cast ingots, or slabs, of aluminium are heated to around 500 ºC, depending on the final properties required, and then passed repeatedly backwards and forwards through high pressure rollers, getting longer and longer and thinner and thinner. The width of the metal is maintained, with additional length cut to size at plate gauge, or coiled onto a spool at about 3mm thick (intermediate gauge), ready for further treatment to produce finished sheet and foil gauges.
The intermediate gauge aluminium coil is then cold-rolled - usually reel to reel through a series of pressurised rollers - to final gauge specification. At this stage, any specified coatings or lacquers are applied, before the coil is edge-trimmed ready for shipment to the customer.

The rolling of aluminium changes its metallic structure and the metal takes on new characteristics and properties. The brittleness of the coarse cast structure is replaced by a stronger and more ductile material, with degrees of strength and ductility controlled by rolling pressure and number of passes, as well as alloy composition. A thermal annealing process may also be employed after hot and cold rolling, to ensure the correct balance between flexibility and strength for different applications.

Careful attention to the mechanics and chemistry of the rolling process has enabled fine surface finishes and, most importantly, gauge uniformity, to be achieved - crucial benefits for the production of drinks cans, foil packaging and auto-body parts.

Can-making and filling

Foil Packaging