Transport behavior of PP in a plastication screw of an injection molding machine: Comparison of standard screw and barrier screw

Injection molding consists of a series of process, filling, packing, cooling, and then ejection. Resin in the cylinder of injection unit should be rapidly plasticated before a metering region within cooling time. In this study, plastication of PP resin inside a cylinder of an injection molding machine was investigated. The screws used for the experiment were a standard screw and a barrier screw. The length of melted resin (plastication) was compared for RPM. When steady state reached after plastication, the throughput, back pressure, and torque values were measured and compared. After pull out the screw, the cross-section of the resin adhered on the screw channel was investigated. The degree of plastication, and the length of melted resin, which indicates the start and end of resin melted on the screw, were investigated for each screw.