| 摘要 |
A bulge, formed in and cut from an end closure central panel, is reformed into an opening tab by reducing the bulge height and its sidewall angle to extend its brim horizontally outward under the rim of the opening from which the bulge is cut, and the brim is coined to further extend it under the rim. Alternatively, an outwardly extending shoulder can be formed in the bulge sidewall, and ironed out to cooperate with the reduction in bulge height in extending the bulge brim outward under the rim. During reforming and coining, the bulge/opening tab is held in a substantially horizontally fixed position relative to the rim to provide a uniform brim-to-rim underlap.
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