The typical dimension of aluminum can top is based largely on the Can Manufacturers Institute (CMI) standard, such as diameter, thickness and opening configuration. The typical top diameter of mainline drink cans (say, 330 ml cola cans) is 66.0 mm±0.15 mm (the same as the can body diameter of 66.3 mm), and the thickness is 0.20-0.30 mm (the top of carbonated beverages cans should be ≥0.25 mm to hold an internal pressure of ≥90 psi). For example, Ball Corporation’s 202-diameter can lid with a diameter of 66.0mm outside can be used on 78% of the can manufacturing lines throughout the world. One lid can withstand up to 140 N compressive force (tested as per EN 14594), and the width of the sealant coating is 1.2mm ± 0.1mm, resulting in a leakage rate of < 0.01%.
Special-purpose can LIDS come in various sizes. For example, cans of energy drinks (e.g., a 250 ml can of Red Bull) employ a 204 diameter (outer diameter 52.4 mm, height 145 mm), and the lid thickness of the can is increased to 0.28 mm to fit the reduced diameter design of the body of the can; The size of the aluminum lid of food cans (e.g., pet food cans) can be up to 153.4mm (603 diameter), the thickness is 0.35mm, and the compressive strength is ≥300 N (ISO 90 test). Industrial spray cans (such as insecticide cans) use can LIDS with a diameter of 76.2mm (307 diameter), thickness 0.30mm, featuring double-layer sealing rings (EPDM rubber + polyurethane) to withstand corrosion by organic solvents.
Environmental protection and lightweighting are leading the way in size innovation. Data from the European Aluminium Institute (EAFA) in 2023 show that the average thickness of can LIDS has decreased from 0.28mm in 2010 to 0.22mm (21.4% reduction), but the compressive strength has been maintained at ≥ 120N through structural optimisation (e.g., wavy edge design). For instance, Crown Holdings’ EcoEdge® reduces the weight of can LIDS by 10% (2.2g to 2.0g per lid) and, with 10 billion cans produced annually, saves 2,200 tons of aluminium (reducing CO₂ by 16,500 tons).
Custom sizes meet the segmented demands. Craft beer cans (e.g., 500 ml cans) have a 211 diameter (72.0 mm outer diameter), can lid thickness 0.27 mm, and the pull ring lift force is ≤15 N (25 N for regular can LIDS). The 190g instant soup cans commonly marketed in the Japanese market are aluminum can lid with 99.0mm diameter (509 diameter), 0.40mm thickness, and high-temperature sterilization resistance (121°C×60 minutes), and the opening torque of the lid is ≤3 N·m. In the Smithers report, global custom can cap market size in 2023 was $3.7 billion and grew by an annual 8.2% (the usual can cap market growth rate was 3.5%).
In terms of affordability and supply chain efficiency, the standard size unit price of can LIDS (e.g., 202 diameter) is approximately 0.02 per unit (bulk purchase price), while that of custom-made can LIDS (e.g., non-round or irregularly sized openings) is up to 0.05-0.08 per unit. Estimates by the Ardagh Group of the United States suggest that for every 1mm increase in the diameter of the can lid, the mold cost of the production line rises by 12%. Large-scale production (≥ 100 million per year), however, can reduce the marginal cost to 0.003 per unit. For instance, Anheuser-Busch InBev has slashed 18 million yuan in mold cost annually by normalizing the worldwide can lid size (202 diameter), and enhanced filling line efficiency by 17% (the failure rate from 1.2% to 0.5%).
Size design is driven by regulations and recyclability compatibility. The EU’s “Packaging and Packaging Waste Directive” (PPWD) requires the separation of can LIDS from can bodies to allow recycling, making it easier for the “Peel-off lid” type whose diameter tolerance shall be ≤± 0.05mm to fit into the sorters. For example, Tetra Pak’s HeliCap™ 23 aluminium cap (diameter of 31 mm) is used on Tetra Pak milk products, and recycling level increased to 92% (and the standard aluminum foil composite cap to 68% only). According to the Aluminum Institute of America, the recycling/reuse rate of standardized can LIDS has reached 74% (aluminum can overall recycling rate worldwide is 69%), and merely 5% of primary aluminium’s energy requirement needs to be tapped per tonne of recycled aluminium (saving CO₂ equivalent to 9.5 tonnes).