Beverage Can End Bead Structure for Buckle Resistance
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Solution Overview
Problem
Beverage can ends made from down-gauged metal blanks face challenges in maintaining strength, particularly in resisting buckle and tab-over-chime issues due to pressurized contents and manufacturing variability, leading to potential premature fracture during distribution and use.
Innovation Solution
The design incorporates a can end with a circumferential curl, U-shaped countersink, and a center panel featuring a displaceable tear panel and a tab, along with additional material in the circumferential panel to form a substantially vertical radially inner wall, which increases buckle strength and reduces dimensional variability through reforming processes in the conversion press.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of substance
If the thickness of the metal used to make the ends is reduced, then the cost of metal is saved, but the buckle strength and resistance to tab-over-chime deteriorate
Solution Approach 1:
The patent applies local quality by creating a bead feature in the circumferential panel that concentrates additional material at a specific location. This bead provides localized reinforcement to resist buckle and tab-over-chime forces without requiring increased thickness throughout the entire end structure, thus saving metal overall while maintaining critical strength properties.
Solution Approach 2:
The invention transitions from a two-dimensional thin metal blank to a three-dimensional structure by forming a bead that adds volumetric material. This dimensional change allows the end to maintain strength with thinner gauge metal by utilizing the third dimension (depth of the bead) to provide reinforcement where needed.
2Loss of substance
If the thickness of the metal used to make the ends is reduced, then the cost of metal is saved, but the resistance to tab-over-chime deteriorates
Solution Approach 1:
The bead feature provides localized reinforcement at the circumferential panel where tab-over-chime forces are most likely to cause failure. This concentrated material addition addresses the specific reliability issue without requiring uniform thickness increase across the entire end structure.
3Manufacturing precision
If manufacturing variability is reduced through reforming, then the consistency of the can end improves, but the complexity of the manufacturing process increases
Solution Approach 1:
The reforming process is integrated into the existing conversion press operation, performing the dimensional stabilization action at the appropriate stage in the manufacturing sequence. By incorporating the reforming step into the standard conversion process rather than adding a separate operation, the manufacturing precision is improved without proportionally increasing overall process complexity.
Data Source
AI summary
A can end has a public side and an opposing product side. A circumferential curl is located about a center axis and defines an outer perimeter of the can end. A circumferential wall extends downwardly from the curl. A circumferential, generally U-shaped countersink extends radially inwardly from the circumferential wall relative to the center axis and upwardly. A center panel extends radially inwardly from the countersink relative to the center axis and has a displaceable tear panel defined by frangible score and a hinge segment on the public side and a tab fixed to the public side which has a nose portion overlying a portion of the displaceable tear panel. A circumferential panel joins the countersink with the center panel and has a first panel radius joined to a second panel radius by a short wall extending upwardly and inwardly. The circumferential panel has a bead formed therein.