Method and apparatus for making a can lid shell

Abstract

A method and apparatus for making can lid shells in die presses, with the addition of a forming ring within the die set. The forming ring is placed between the draw pad and die center, and is used to apply a force on the material during the shell lid forming process. Use of this apparatus reduces the amount of force that must be applied on the draw pad to hold the material between the die core ring and the draw pad during the forming process. By lessening the force needed to hold the material during the forming process, the probability of wrinkling or cracking of the material during the forming process is greatly reduced.

1 . A process for making a shell for a can lid, the shell comprising a central panel, a countersink, and a seaming panel comprised of a connecting portion and an outer portion, the process comprising: 
 a) holding a material in a tool die between a die core ring and a draw pad using a force of less than 1100 pounds, the die core ring having an outer portion, a connecting surface profile, and an inner diameter;    c) engaging a portion of the material that will form the central panel against a die center in the tool die, the die center having an outer diameter that is less than the inner diameter of the die core ring;    d) moving the die center in a direction to form the central panel of the can lid shell;    e) moving a forming ring placed between the draw pad and the die center in a direction to form the connecting portion of the seaming panel of the can lid shell, the forming ring having a forming surface and being positioned between the draw pad and the die center;    f) further moving the die center and the forming ring in a direction to form the central panel and the connecting portion of the seaming panel until a surface of the die center and the forming surface of the forming ring engage the material;    g) engaging the material that will form the connecting portion of the seaming panel of the can lid shell between the connecting surface profile of the die core ring and the forming surface of the forming ring; and    h) further moving the die center and the forming ring in the direction to form the central panel as the forming ring continues to support and apply force to the material between the forming surface of the forming ring and the connecting surface profile of the die core ring.