How Are Aluminum Cans Made?

How many pieces make up an aluminum can? Learn how cans are put together during the manufacturing process.

How Cans are Made

1. Cup Forming — The process starts with a coiled aluminum sheet which is fed through a press that punches out shallow cups.
2. Redrawing & Ironing — Cups are fed into an ironing press where successive rings redraw and iron the cup and reduce sidewall thickness to achieve a full-length can. The bottom is domed to obtain strength required to withstand internal pressure.
3. Trimming — Cans are spun as a cutting tool trims the rough shell from the inside.
4. Cleaning — The cans are cleaned and pre-treated for decoration and inside coating with the following steps:
   1. Pre-clean with water rinse
   2. Clean with commercial cleaner
   3. Cold water rinse
   4. Conditioning
   5. Cold water rinse
   6. Deionized water rinse
   7. Drying
5. Printing & Varnishing — Cans are rolled against a rubber cylinder to print up to four colors simultaneously, then moved to another station where a clear protective overvarnish is applied.
6. Bottom Varnishing — Cans are moved past an applicator that applies a protective varnish to the bottom.
7. Baking — Cans wind through a conveyor in an oven to dry the printing.
8. Inside Spraying — A specially selected coating is sprayed on the inside of the cans.
9. Baking — Cans are conveyed through a tunnel oven that bakes and cures the inside coating.
10. Necking and Flanging — Cans are necked-in at the top to reduce can diameter and flanged to accept the end.
11. Light Tester — Clean cans are cycled through a light tester that detects pin holes and rejects defective cans.
12. Palletizing — After final inspection cans are palletized for shipments to the customer.

End-Making

1. Stamping — Ends are stamped out of pre-coated aluminum coil. Compound is added to assure a perfect seal between can and end at the customer’s plant.
2. Rivet Making, Scoring and Tabbing — Ends are fed through a high precision press where rivet making, scoring and tabbing occur in consecutive operations.
3. Shipping — Ends are bagged and placed on skids for shipment to the customer.