Patent ID: 6235229
Filing Date: 2001-05-22
Classification: B29C

Abstract:
A coinjection method, for use with a multi-cavity coinjection mold having a relatively large plurality of mold cavities for simultaneously molding a relatively large plurality of multi-layered articles, comprising the steps of:dividing the relatively large plurality of cavities into a plurality of cavity groups of mold cavities, each group defining a relatively small plurality of said mold cavities;providing a supply of a first and a second molding material;providing a first hot runner system in communication with said supply of first and second molding materials;using said first hot runner system for conveying said first and said second molding materials separately to a region proximate each cavity group;providing a valve mechanism per cavity group for receiving said first and second molding materials from said first hot runner system;using each valve mechanism to sequentially supply desired quantities of said first and said second molding materials contiguously to a single balanced hot runner for the associated cavity group, wherein each hot runner communicates with a single cavity group only; andcontrolling the temperature to maintain the desired respective temperatures of said first hot runner system, hot runners and said cavities.