Patent ID: 6968724

Claim:
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: holding a material in a tool die between a die core ring and a draw pad by application of a force to the draw pad in the direction of the material just sufficient to hold the material between the die core ring and the draw pad, the die core ring having an outer portion, a connecting surface profile, and an inner diameter; 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; moving the die center in a direction to form the central panel of the can lid shell by means of application of a counterforce to the die center; moving a forming ring having a forming surface and being positioned between the draw pad and the die center until the forming surface of the forming ring engages the material that will form the connecting portion of the seaming panel of the can lid shell; applying a force to the forming ring in the direction of the material to 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; continuing to apply a force to the draw pad just sufficient to hold the material in position between the die core ring and the draw pad and prevent the formation of wrinkles in the seaming panel of the can lid shell; further moving the die center 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; reversing the direction of movement of the die center; engaging the central panel of the material with a panel forming punch having an outer diameter less than the outer diameter of the die center; and moving the panel forming punch in a direction toward the material to form the counter sink while 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.