Influence of Polymer Fluidity Using Vacuum Assisted Injection Process

Abstract

Injection molding of small and complex products is often a problem in injection because, in very narrow and very small areas, such as the sharp end of the workpiece (sharp burrs), the plastic melt cannot enter the cavity or short shot. Finally, the product was rejected. Researchers have studied and applied vacuum ventilation for removing air from the mold cavity. This research investigated the effects of compressed air and examined the dynamics of molten plastics in different shapes to compare between normal injection and vacuum-assisted injection and observe the behavior of the plastic flow in various shapes that can help reduce the compressed air trapped in the mold cavity. By selecting materials, plastic grades PBT and PBT, mixed with fiberglass 30% and using a plastic specimen with a Rib and Boss (small size) under the same injection conditions comparison between conventional injection and vacuum-assisted injection. The results of the experiment show that the use of a vacuum system to assist in the molding process injection process allows plastics to flow better than conventional injection molding up to 2.11%.