Method and system for reducing polymer degradation products in two stage injection molding machines

摘要

A method and system of operating a two stage injection molding machine wherein movement of the injection plunger in the shooting pot is co-ordinated with movement of the plasticizing screw and melt flow into the shooting pot such that the plunger provides minimal resistance to the melt flow into the shooting pot while avoiding the production of voids or air inside the melt. The undesired shear forces to which the melt is exposed are thus reduced, correspondingly reducing the melt degradation products which would otherwise result.