Temperature control of thermoplastic preforms in a container blow molding process involves non-uniform cooling of preforms from a molding cycle prior to molding

摘要

Thermoplastic melt is injected into a number of cavities to form preforms(38). In order to compensate for different degrees of cooling after leaving the molding tool and ensure uniform properties in preforms presented to the blowing station(24) the preforms are cooled non-uniformly. An Independent claim is made for the process equipment which includes a preform injection molding machine with one or more cooling units for controlling preform(38) temperature before demolding from the tool cavities and a control system which determines the non-uniform cooling of preforms in the cavities.