| 摘要 |
A food can end or shell is formed from a thin metal sheet by blanking a circular disk from the sheet, gripping a peripheral portion of the disk, pressing a center portion of the disk upwardly relative to the peripheral portion, and forming upwardly projecting concentric beads within an annular portion of the disk. Thereafter, an annular chuck wall, countersink and crown portion are formed within the disk around the concentric beads. A downwardly projecting annular bead is formed within the bottom wall of the countersink and cooperates to resist buckling of the shell.
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