Beverage can manufacture — drawing, ironing and the pressure case
A thin-walled pressure vessel made by cold work, where the internal pressure is part of the structure.
Material
Body stock is typically 3104-H19; the end uses 5182 for its higher strength. Two alloys because the body needs formability and the end needs to hold a score line that opens reliably and not before. (Broadly true: The general process is documented; details vary by manufacturer.)
Draw and wall ironing
A cup is drawn then pushed through progressive ironing rings. Wall thickness falls to roughly 0.097 mm while the base stays several times thicker — the base is the pressure-bearing part and is domed to resist inversion. (Broadly true: The general process is documented; details vary by manufacturer.)
Why the dome
A flat base would buckle outward under carbonation pressure. The concave dome puts the base in compression and is the reason a can can be that thin at all.
The structure includes the contents
An empty open can crushes easily; a sealed carbonated one supports a substantial axial load because internal pressure stabilises the wall. That is a design assumption, not a bonus.
Necking
Diameter reduction happens over many small steps rather than a few large ones, because each step risks wrinkling. More stations means less material in the end, which at these volumes is the whole economic argument. (Broadly true: The general process is documented; details vary by manufacturer.)
Where this comes from
The Aluminum Association — can recycling and manufacture; Ball Corporation — beverage can manufacturing. Every stage above is marked with how confident we are in it, and an uncertain one says so rather than reading like the rest.
- Difficulty: industrial.
- Time: milliseconds per can.
- Written for: engineer — Tolerances, materials, formulae, and the failure modes.
Questions
How is aluminium drinks can made?
A flat disc is drawn into a cup, ironed thinner than paper against a wall, and necked to take a lid — hundreds of times a minute. The stages above set it out at the engineer level.
Can I build this myself?
This is an industrial process rather than a home build, so it is described rather than instructed.