A dome of a domed aerosol can end is initially formed and then a crown of
the can end is formed so that material flow within a workpiece from which
the can end is formed is controlled to substantially eliminate wrinkling
problems associated with the use of sheet material which is thinner than
conventionally used, for example double reduced steel. The peripheral
portion of the workpiece is initially clamped between a blank punch and a
draw pad, and also between a knockout and a crown ring. An outer first
portion of the dome is then formed by an outer redraw sleeve and a dome
form die. An inner second portion of the dome is next formed by a dome
punch and the dome form die. There may be limited contact of the dome
punch with the workpiece during formation of the first portion of the dome
and the workpiece may also be clamped between the outer redraw sleeve and
the dome form die during formation of the second dome portion. Controlled
clamping between the blank punch and the draw pad, between the knockout
and the crown ring and between the outer redraw sleeve and the dome form
die control material flow for improved formation of the domed aerosol can
end with effective elimination of radial wrinkles associated with prior
art forming methods and apparatus.
