Can Making

There are two major aluminium products for can manufacturers:

• body stock from which the can body is made
  
• end stock from which the top and tab of the can are made.
  

The can body and the tops (end and tab) of the can are manufactured separately. The can fillers attach the end to the can after it has been filled.

Can (body) making

There are seven basic stages in making the body of the can.

Stage 1 Lubrication

A thin film of lubricant is applied to the aluminium as it is uncoiled. This lubricant helps the metal pass through the rigorous can making process.

Stage 2 Cupper

A circular blank of aluminium is cut out and passed into the cupper machine where the blank is drawn into a cup.

Stage 3 Bodymaker

The cup is moved into the bodymaking machine where the cup is pulled out (or ironed out) to produce a can and the dome on the can bottom is formed.

Stage 4 Trimmer and washer

The top of the can is trimmed off to a uniform height and the can is then washed.

Stage 5 Decoration

Decorative ink is applied to the outside of the can and then the can passes through to an oven where the inks are dried (or cured). A spray is also added to the inside of the can and this is also dried.

Stage 6 Necker and flanger

The can passes through a machine that 'necks in' the can opening, making the can end smaller. The flanger creates a lip on the top of the can so that the top of the can can be attached after it has been filled.

Stage 7 Quality test and packing

The can passes through a light test, which checks the can for possible leaks (holes) and physical damage. The cans are then placed on pallets and transported to the filler.

End (end and tab) making

Different plants make can ends and tabs, and can bodies.
There are four stages in making the end of a can.

Blank and shell formation

At a single stroke of the press a circular blank is cut and the 'countersink' and 'pre-curls' formed. This makes the shell.

Curling

A curler machine continues to form the pre-curl until the correct curl height is obtained.

Compounding

A small quantity of compound or sealant is applied inside the curl. This ensures a pressure-tight seam when the end is attached to the can after it has been filled.

Conversion

During the conversion process, the shell is put through a 'progression' where a bubble is formed in the metal to create a rivet. The end is scored, which allows the end to open around the scoreline (called the aperture).

At the same time, the conversion press is also manufacturing the tabs from a separate tab strip. Tabs can come in different colours eg blue, green or gold. The tab is staked onto the rivet. This flattens the rivet and attaches the tab to the end.

During the progression stage, the end is also embossed with words such as 'Do not litter' and 'Please recycle'.

The finished end is then bagged, palletised and sent to the customer.