Elastic mold and method of molding for undercut articles

摘要

A one piece mold, having a cavity into which fluid material is fed through an input port, to result in a seamless, cast icon. At least the input port portion of the mold is sufficiently elastic so that it can be stretched open: (a) by the hardened icon, when positive pressure is applied into the cavity, remote from the input port; (b) by negative pressure applied around the mold, at least proximate to the input port; or (c) by a combination of such applied positive and negative pressures; to demold through the input port, the then hardened icon. An endless conveyor system carries the molds past several stations, including an icon demolding station, which applies the mold stretching pressure for the icon domolding. The applied pressure(s) does not exceed the elastic capability of the mold, so that it can be reused repeatedly, without deterioration as to form and shape of the icon.