Melt Extrusion Process
Melting in the Screw
From left to right during processing, melting takes places. The material being melted remains behind in the solid material. This is why, if we do not use a sufficient compression ratio and an appropriate length of the compression zone, there will be some unmelted material left in the metering zone. This would result in a rough surface on the profile. We must ensure that the material coming to the metering zone has been completely melted.
Melting in the Conventional Screw
How to Guarantee Melting, Barrier Screw
Extra barrier flights allow for extra compression during the melt transition from the filling to the metering zones. This compression provides extra melting due to the increasing shear.