Single action press for manufacturing shells for can ends

A method for manufacturing a shell for a can end in a single action press, said press having a down stoke followed by an upstroke, comprising the steps of:

• 1 in said down stroke,
• a) clamping a sheet of end material between first and second opposed tools in said press;
• b) performing a forming operation to form said shell from said sheet of end material with a die center in said first tool;
• 2 in said upstroke,
• a) initially retaining the clamping of said sheet of end material between said first and second tools,
• b) while said clamping in step 2 a) is performed, moving said center die insert into a condition of disengagement from said shell;
• and
• c) releasing the clamping in step 2 a) and thereafter removing said shell from said press;
• wherein said first tool comprises a die center piston coupled to said die center insert and an actuator pin engaging said die center piston, and wherein said upstroke step 2. father comprises the step 2.d) of actuating said pin as to move said die center piston to thereby allow compressed gas to enter a cavity above said die center piston and exert an axial force on said die center piston.