Pressure-Resistant Can Shell Countersink Geometry for Seaming Stability
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Solution Overview
Problem
Existing pressure-resistant easy open ends for beverage cans suffer from high breakage rates under pressure and unstable can seaming due to inadequate material distribution and contact area with the seaming mould, leading to safety and quality issues.
Innovation Solution
The design incorporates a countersink portion with additional geometric features such as a sixth arc portion and second straight portion, optimizing the radii and connections to reduce breakage probability and enhance contact area with the seaming mould, maintaining pressure resistance while improving safety and stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of substance
If the countersink portion is connected only by the first straight portion, fourth arc portion and fifth arc portion with externally tangent connection, then the material usage is reduced, but the pressure resistance reliability deteriorates with 80% breakage rate
Solution Approach 1:
The countersink portion is divided into multiple segments: first straight portion, fourth arc portion, fifth arc portion, sixth arc portion, and second straight portion. This segmentation allows each portion to bear specific stresses, distributing the pressure load more effectively and reducing breakage while maintaining material efficiency.
Solution Approach 2:
The design incorporates multiple arc portions (fourth arc portion, fifth arc portion, sixth arc portion) with specific radius ratios to create smooth curved transitions. These curved structures better distribute stress concentrations compared to sharp corners, significantly improving pressure resistance reliability while maintaining material efficiency.
2Ease of manufacture
If the fourth arc portion and fifth arc portion are connected in externally tangent way, then the manufacturing is simplified, but the structural strength deteriorates causing high breakage probability
Solution Approach 1:
The fourth arc portion and fifth arc portion are designed with specific radius ratios (R5/R4 between 0.5-2.0) to create optimized curved transitions. This curvature design distributes stress more evenly during pressure testing, maintaining structural strength while preserving manufacturing simplicity through continuous curved surfaces.
Solution Approach 2:
The invention optimizes specific geometric parameters including the radius ratio of fifth arc portion to fourth arc portion (R5/R4 between 0.5-2.0) and the position of the sixth arc portion. These parameter adjustments enhance structural strength to resist pressure-induced breakage while maintaining ease of manufacture through standardized curved geometries.
3Device complexity
If the connection of countersink portion and ferrule arc section is externally tangent connection of arc to arc, then the structure is simplified, but the contact area with seaming mould is too small causing unstable can seaming
Solution Approach 1:
The connection between countersink portion and ferrule arc section is segmented into multiple portions: fifth arc portion, sixth arc portion, and second straight portion. This segmentation creates a longer, more distributed contact area with the seaming mould, improving can seaming stability while maintaining relatively simple structural geometry.
Solution Approach 2:
The invention extends the contact area from a single arc-to-arc point contact to a multi-dimensional contact zone involving fifth arc portion, sixth arc portion, and second straight portion. This dimensional expansion of the contact interface improves seaming stability without significantly increasing overall structural complexity.
Data Source
Figure 1~2
Figure 3~4
AI summary
The present invention relates to a pressure resistant basic shell, easy open end and can with easy open end, and the basic shell consists of a can seaming portion, a countersink portion, a ferrule arc portion (R7), an upward extension portion of ferrule and a center panel from periphery to center in the cross section; the countersink portion also consists of a sixth arc portion (R6) and a second straight portion (L2), and the sixth arc portion (R6) and the second straight portion (L2) are connected in a tangent way, and the second straight portion (L2) and the ferrule arc portion (R7) are connected in a tangent way; the center (Y6) of the sixth arc portion (R6) is located below the upper surface of the center panel (L4). The break probability under the failure of pressure resistance of the present invention is lowered to 0.05%∼2.5%, which significantly improves the safety of use.