MOLDING APPARATUS AND METHOD FOR PRODUCING ARTICLES MOLDED THROUGH SEQUENTIAL INJECTION

摘要

A molding apparatus for the production of articles molded through sequential injection includes a mold having a cavity, a plurality of electrically actuated injectors arranged at central, intermediate and end positions, respectively, with respect to the mold cavity, and an electronic system for controlling the injectors for the actuation thereof according to a sequential cycle which provides for opening the central injector first, followed by the intermediate injectors and then the end injectors. The electronic control system is configured so that the opening sequential cycle occurs in such a way to obtain more linear and homogeneous pressure in the mold filling step, and lower packing pressure.

主权项

1. A molding apparatus for the production of articles molded by sequential injection, comprising a mold having a cavity, a plurality of electrically actuated injectors including a central injector, intermediate injectors and end injectors arranged at a central, intermediate and end positions, respectively, with respect to the mold cavity, and an electronic control system controlling the injectors for actuation thereof according to a sequential cycle which provides for opening the central injector first, followed by the intermediate injectors and then the end injectors, characterized in that wherein said electronic control system is configured in such a way that:
the central injector is opened in a relatively rapid fashion up to a maximum opening value, then held at said maximum opening value, then partially closed to a minimum opening value and held at such minimum opening value, and the intermediate injectors and the end injectors are opened in succession in a less rapid fashion up to respective maximum opening values lower than said maximum opening value of the central injector and higher than said minimum opening value of the central injector, subsequently held at said respective maximum opening values, and then partially closed down to respective minimum opening values higher than said minimum opening value of the central injector and held at such minimum opening values.