Method and apparatus for forming a can shell

Abstract

A mechanical press receives can shell tooling having multiple stages each including a plurality of shell forming stations. Each station has an annular blank die which forms a sheet metal disk, and a peripheral portion of each disk is gripped between the blank die and a lower pressure sleeve. The peripheral portion of each disk is shifted downwardly relative to a center portion of the disk to start the forming of a center panel within the disk between an annular nose portion of an air pressurized die center and an air pressurized panel punch. The peripheral portion is also gripped between an air pressurized lower die core ring and an air pressurized upper sleeve which cooperate to form a crown and a depending lip. The center panel of each disk is shifted downwardly by the die center and the panel punch for forming a chuckwall against the die core ring and to start a countersink by wrapping the metal around the nose portion of the die center. As the die center and upper sleeve bottom are moving upwardly, a substantially cylindrical panel wall is formed between the nose portion of the die center and the panel punch, and the countersink is precisely formed around the nose portion. The lower tooling at each stage is positioned at a slightly different elevation so that the upper tooling contacts the lower tooling at staggered or sequential time intervals for significantly reducing the dynamic loading on the press.