Full Aperture Can End Vent Score Geometry
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Solution Overview
Problem
Conventional full aperture can ends fail to achieve robust venting for high-pressure applications, such as soda cans, with existing designs either lacking sufficient vent test ratings or being unsuitable for very high internal pressures, leading to potential score rupture and panel failure during opening.
Innovation Solution
A full aperture unseamed can end design featuring a unique vent score geometry with a central portion proximate to the rivet, check slots, and specific dimensions that enhance the vent test rating by controlling the rupture propagation, allowing for safe venting at pressures above 620.5 kPa (90 psi).
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional vent score designs are used in full aperture can ends, then the structure is simple and easy to manufacture, but the vent test rating is insufficient for high-pressure applications (below 620.5 kPa)
Solution Approach 1:
The vent score is segmented into multiple functional zones: a central portion with increased residual thickness spaced from the rivet, check slots positioned radially outward, and lateral portions connecting these features. This segmentation allows different regions to perform specific functions - the central portion controls initial rupture timing, check slots arrest propagation, and lateral portions guide the rupture path, collectively achieving the required vent test rating
Solution Approach 2:
The vent score exhibits non-uniform local properties with varying residual thickness throughout its length. The central portion has increased residual thickness compared to other segments, creating localized strength variations that control the sequence and timing of rupture. This local quality differentiation enables precise control over pressure release characteristics while maintaining overall structural integrity
2Reliability
If check slots are added to arrest score rupture propagation, then safe venting is achieved, but the vent score geometry becomes more complex
Solution Approach 1:
Check slots are pre-positioned along the vent score path at locations calculated to arrest rupture propagation before it reaches critical areas. These features are built into the score geometry during manufacturing, so that when rupture occurs under pressure, the propagation is automatically arrested by the pre-planned thicker residual sections, ensuring safe venting without requiring additional active components
3Reliability
If the central portion of the vent score is spaced apart from the rivet, then vent test rating increases above 620.5 kPa, but the distance precision requirement increases
Solution Approach 1:
The spacing distance between the central portion and rivet is optimized as a critical geometric parameter. By carefully controlling this distance within specific ranges, the rupture timing is adjusted to achieve the target vent test rating of at least 620.5 kPa. This parameter optimization balances the competing requirements of achieving sufficient strength while maintaining manufacturability
Data Source
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AI summary
A full aperture unseamed can end having a vent test rating of at least 90 psi comprising a center panel (24) having an periphery and including a coined portion proximate a rivet (30), a first score (26) defining a removable panel (34), a tab (32), including a nose (31), mounted to the removable panel (34), and a second score (40) disposed on the removable panel, the second score having (i) a central portion (42) spaced apart from the coined portion; (ii) a pair of check slots (45a, 45b) disposed on either side of the central portion; (iii) a pair of lateral portions that extend from the check slots; and (iv) a pair of side portions (50a, 50b) that extend from the lateral portions, respectively.