Can lids are manufactured by a very efficient and accurate process, combining advanced technology with durable materials and strict quality control. Generally made of aluminum or steel, the lids are designed to be lightweight, strong, and recyclable, meeting both functional and sustainable demands.
First, the manufacturing of sheet metal is started, where sheets of aluminum or steel are rolled on to a constant thickness of about 0.2 to 0.3 millimeters. These sheets are further coated with a layer for protection against corrosion, thus adding more years to their life. Sheets, after being coated, are fed into high-speed presses fitted with deep-draw stamping technology that stamps the lid shape out and produces up to 1,500 lids per minute.
Every lid is curled, a process that rounds the edges to fit tightly onto the can body. The curl on a lid is designed so that it can create an airtight seal in the can, capable of sustaining up to 90 pounds per square inch of internal pressure, which is essential for keeping beverages carbonated.
After forming, there is a slight depression for the stay-on tab, a design adopted in 1975 to replace pull tabs. The tab is fastened through riveting machines, which fasten it onto the lid without puncturing it, making it strong and preventing chances of leaks. The mechanism of this stay-on tab requires about 2-3 pounds of force while opening, hence making it safe and accessible.
The lids of cans are further tested for strength and safety. Each lid undergoes a pressure test, along with visual scanning, to ensure uniformity in compliance with international standards for packaging. Whatever defects it may have, like weak seams or uneven shapes, are outright rejected.
Sustainability plays a core role in the manufacturing of can lids: the primary material, aluminum, is 100% recyclable and, more importantly, will re-enter the production cycle in as little as 60 days. A company often incorporates up to 70% recycled content in its lids and reduces raw material extractions with a related decrease in carbon footprint.
Major manufacturers like Ball Corporation and Crown Holdings dominate the global production of can lids, supplying billions annually to beverage giants such as Coca-Cola and PepsiCo. In 2021, over 200 billion can lids were produced worldwide, underscoring their critical role in the packaging industry.
The Coca-Cola Company’s World Without Waste initiative depends on the recyclability of lids for cans in order to achieve its commitment of collecting and recycling one can or bottle for every can or bottle sold by 2030. This commitment shows the environmental relevance of efficient lid manufacturing.
As Dieter Rams, an industrial designer, once said, “Good design must also be sustainable.” This is exemplified by the manufacturing process of lids for cans, combining precision in engineering while being environmentally responsible to meet the needs of both consumers and the planet.