In Bill Hammack’s Youtube video, the ingenious design of the aluminum beverage can is revealed. It’s amazing how many Inventive Principles are applied in such a humble, everyday object.
The aluminum can begins life as a round disc which is repeatedly pressed into a successively narrower cylindrical cup shape. This cup is deliberately made too tall for the intended can, and the top is trimmed. This is Principle 16 – Excessive Action, and is easier than achieving the degree of precision needed to form a precise mating edge for the can’s top without trimming.
The bottom of the can is domed inward. This is an example of Principle 14 – Spheroidality & Curvature, taking advantage of the strength of curved structures in order to resist the internal pressure of the can.
A thin film of lacquer is applied to the inside of the can to prevent the beverage from tasting metallic – Principle 30 – Flexible Membranes/Thin Films.
Filled cans are pressurized, either with nitrogen (to keep the beverage fresh – Principle 39 – Inert Atmosphere) or carbon dioxide for carbonated drinks. This pressure keeps the can rigid – Principle 29 – Pneumatics and Hydraulics.
The lid holds the pull tab which is used to open the can, eliminating the need for a separate tool – Principle 5 – Merging.
The tab actually does two jobs (Principle 6 – Universality) by first piercing the can to release the pressure and then levering the opening into the can.