Beaded Can End Forming With Controlled Thinning and Minimal Stretching
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Solution Overview
Problem
The manufacturing of metallic beverage can ends faces challenges in achieving high strength and light weight while minimizing material stretching and thinning, which can lead to inconsistencies and reduced strength.
Innovation Solution
A method and apparatus for forming can ends in a forming press that involves positioning a sheet of material between an upper punch assembly and a fixed base assembly, cutting a can end blank, and using a series of annular bead punches and dies to form the can end with controlled thinning and minimal stretching, ensuring the central panel section remains clamped throughout the process.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If aggressive material working is used to achieve high strength from thin materials, then strength is improved, but material stretching and thinning increase leading to inconsistencies
Solution Approach 1:
The forming process is divided into multiple sequential stages: initial blanking, first bead formation, second bead formation, and final countersink formation. Each stage uses specific punches and dies to form particular features, allowing controlled deformation at each step rather than aggressive single-stage forming, thus maintaining contour consistency while achieving strength
Solution Approach 2:
The peripheral portion of the blank is clamped between the crown ring and knockout ring before forming operations begin. This preliminary clamping stabilizes the blank and prevents unwanted deformation during subsequent forming stages, ensuring consistent contour formation while still allowing necessary material working for strength
2Weight of moving object
If thin materials are used to reduce weight and manufacturing cost, then weight and cost are reduced, but material stretching and thinning during forming increase
Solution Approach 1:
Different regions of the blank are treated differently during forming. The peripheral portion is clamped to prevent thinning, while the central panel portion is selectively formed into beads and countersinks. The intermediate area between these regions experiences controlled deformation, allowing thin material to be used overall while minimizing thinning in critical areas
Solution Approach 2:
The forming process uses dynamic sequencing where punches and dies engage the material in a specific order. The first bead punches form initial contours, followed by second bead punches that refine the shape, and finally countersink punches that create the central depression. This dynamic, multi-stage approach distributes deformation evenly through the thin material, preventing localized thinning
3Manufacturing precision
If multiple bead punches and dies are used to form can ends with minimal stretching, then manufacturing precision is improved, but device complexity increases
Solution Approach 1:
Multiple forming operations are merged into a single integrated die set. The crown ring, knockout ring, first and second bead punches, second and fourth bead dies, and countersink punches all work simultaneously on the blank in a coordinated manner. This merging achieves high precision forming while reducing the number of separate tooling changes and operations required
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The method achieves can ends with controlled thinning, preventing warping, twisting, and fractures, while maintaining the required strength and consistency, with minimal material stretching and thinning, typically no more than 6%.
Implementation Method 1
moving the upper punch assembly from a retracted position toward an extended position to form an initial annular countersink radius next to the peripheral portion of the can end blank
Implementation Method 2
clamping a central portion of the can end blank between an upper panel punch and a lower panel punch to define a central panel section
Data Source
AI summary
A method and apparatus for forming a can end in a forming press including positioning a sheet of material between an upper punch assembly and a fixed base assembly; cutting a can end blank from the sheet of material; clamping a peripheral portion of the can end blank; moving the upper punch assembly to clamp a central portion of the can end blank between an upper panel punch and a lower panel punch to define a central panel section positioned below an annular inner bead die located adjacent to the lower panel punch on the fixed base assembly; and extending the upper punch assembly to form an initial annular countersink radius next to the peripheral portion of the can end blank, with a substantially undeformed intermediate area extending between the initial annular countersink radius and the annular inner bead die.