Of the aluminum can LIDS there is sometimes a large opening design. Its main reason is to meet the fluidity needs of fruit-filled or high-viscosity beverages. For instance, in 2023, Coconut Tree Brand coconut Milk widened the opening diameter of the lid of the can from 5.0 millimeters to 6.5 millimeters, enhancing the pass rate of coconut meat particles (3 to 5 millimeter diameter) from 78% to 95%, and reducing the consumer complaint rate by 42%. This design requires the structural toughness – once the opening is expanded, the thickness of the aluminum alloy in the can lid edge will increase from 0.26 millimeters to 0.30 millimeters and the tensile strength will be ≥220 MPa, adding an additional 0.002 US dollars to the cost of one can lid. According to the experimental results at Yamato Can-making in Japan, in order to prevent liquid splashing, for every 1-millimeter increase in the diameter of the opening, the speed of the filling line should be reduced by 5%. However, Starbucks’ ready-to-drink coffee can be filled with an efficiency of 2,800 cans per minute even when there is an 8-millimeter opening if the Angle of the flow channel of the lid of the can is optimized (from 55° to 65°).
The sports drink market has driven the innovation of large-opening aluminum can LIDS. Red Bull’s “Turbo Flow” design, launched in 2024, has increased the opening area by 32% (from 19.6mm ² to 25.9mm ²). Reduce the pouring time of a 500-milliliter drink from 7.2 seconds to 5.1 seconds, meeting the need for rapid hydration after exercise. This structure adopts the arc edge cutting technology, the precision of cutting controlled in ±0.02 millimeters, but the price of the mold increases by 120,000 US dollars for each set. United States tests conducted by the Ball Corporation show that opening force of such can LIDS needs to be raised from 18 Newtons to 22 Newtons for sealing purposes, thereby raising the difficulty rate for opening by elderly consumers from 3.1% to 5.6%. For this reason, Carlsberg developed a two-stage lever structure through a forward adjustment of the position of the fulcrum by 1.2 millimeters. Reduce the applied force by 15% with maintained sealing strength.
Economic and environmental factors also affect the design of opening. The EU’s Packaging Waste Regulation requires can LIDS recycling rates to be at least 90% by the year 2030, while the traditional small opening design suffers from up to 1.8% metal loss during crush and recycle. The EcoWide aluminum can lid launched by Austrian firm Greiner Packaging in 2023 expanded the opening diameter to 7 millimeters, doubling the proportion of fragments larger than 5 millimeters from 65% to 82%. The magnetic separation efficiency increased by 17%, and the purity of recycled aluminum reached 99.65%. Material utilization was increased by 3%, and the overall cost of recycling decreased by $0.015 per can. The application data from Coca-Cola’s German factory shows that this design saves a single line’s yearly aluminum material loss by 4.2 tons and carbon emissions by 9.3 tons of CO₂ equivalent.
Market competition also gives rise to differentiation strategies that force opening sizes to shift. The “MAX Vent” aluminum can cap designed by PepsiCo for the energy drink Rockstar in 2024 features a dual-opening mechanism with a primary and secondary opening. The primary opening is 6 millimeters in diameter for drinking, and the secondary opening is 2 millimeters for balancing air pressure. 40% improvement in release rate of carbonic acid gas and 33% reduction in foam height. This design requires the addition of a gas guide groove 0.8 millimeters deep on the can cover. The stamping is increased from 3 to 5 and the die life reduced from 500,000 times to 350,000 times. According to Nielsen market analysis, the shelf conversion rate of this product increased by 19% at the time of launch, but the production cost per cap was raised by 0.005 US dollars. It requires an annual sales volume of over 800 million cans to be profitable. For comparison, the 4.5 millimeter diameter narrow-opening aroma cap developed by Kirin Beer in Japan has extended the shelf life of the beer from 6 months to 9 months by lowering the oxygen exchange rate (from 0.8 mL/min to 0.3 mL/min), and the complaint rate during the shelf life has decreased by 61%.