IRONING RING TO THIN THE SIDEWALL OF A CUP FORMED FROM POLYESTER/ALUMINIUM LAMINATE OR ALUMINIUM

摘要

Thickness of sidewall of cup (17) drawn from laminate of polyester film and sheet Al or Al alloy is reduced using wall ironing ring (8,11,14) through which a punch (1) is passed, the ring having a frustoconical entry surface (24) converging at 1-4 deg.C to a central axis perpendicular to the plane of the ringlnad terminating at a land (25) of short length. A divergent exit surface (26) extends from the land at 5-15 deg. The ring is made from a wear resistant material having a thermal conductivity greater than 50 watts per metre deg. C.