CO-INJECTION OF MOLDED PARTS FOR WEIGHT REDUCTION

摘要

A molded vehicle component (10) having a skin (14) and a lower density core (16) formed by a co-injection molding process. In a first phase, a first material for forming the skin of class A surface material is injected into a mold to partially fill the mold cavity (104). Thereafter, in a second phase, a second material is injected into the same cavity (104) to complete filling of the mold cavity (104). The second material can flow only to portions of the part where the first material is still molten and displaces the molten core of the first phase, pushing it away from co-injection gates until the mold cavity is full. The second material is pre-treated with a chemical blowing agent in order to reduce part weight by foaming the core material. The finished co-injection molded part (10) has one material on all visible class A surfaces (14) and a core (16) that is a different, less dense material.