NECKING DIE WITH REDRAW SURFACE AND METHOD OF DIE NECKING

摘要

The invention provides a die set comprising an annular necking die and a knockout punch for necking-in a metal container, and a method of necking. In the method, in at least one necking-in step, the metal container is both reduced in diameter and the container wall is redrawn to minimize circumferential irregularities of wall thickness and/or circumferential rippling of the container wall caused by the reduction of diameter. The die of the die set is provided with a redraw surface to achieve this redrawing effect.