of maintaining the sheet in a substantially continuous and void free state allows the sheet to be advanced through the press in a precise and controlled manner. This results in maintenance of proper alignment of the sheet with respect to the tools as the end is formed by the work stations. Accordingly, the press can be operated at high speeds and in a reliable fashion. Also, this feature avoids the registration, elasticity and misalignment problems found with the prior art system, such as the Buhrke press, that attempted to make a complete end from a web or sheet in a single press. The press includes a station that blanks the ends from the sheet when the formation of the ends is complete. The ends are then ejected fromthe press.
In a preferred embodiment, the work stations are organized such that the operations traditionally performed in a conversion press are performed first, and with the shell forming operation performed in the very last step. This is essentially the reverse of the previous technique of forming the shell first and then converting the shell into a end by adding all the end features, such as rivet, tab, pour panel, embossing, etc. By performing the operations on the sheet in the order provided by this invention, the sheet of end material is more readily indexed through the press in a controlled and reliable manner at high speed.
In an embodiment in which the curling is not performed in the press, the ends are fed to a curler station for curling