New extruders may experience problems caused by worn ex […]
New extruders may experience problems caused by worn extruder barrel screws. In addition to the wear on the screw, the barrel can be problematic as well. The screw is a crucial part of the extruder and is a critical component for the smooth and consistent flow of material. Without it, your extruder would fail to run smoothly and produce a sub-par product.
The screw is divided into three zones. The first is the feed zone, which is constant in depth, and the second is the compression zone, which is shallower and prevents air from circulating down the barrel. The third zone, which is the metering zone, is where the plastic is almost melted and is pushed through the die. Typically, the feed zone is more than twice as long as the compression zone, but there is an exception for the latter.
Single-screw extruders have three parts: the feed chamber, the transition zone, and the metering section. In a single-screw extruder, the feed section contains the plastic pellets and the transition zone is the melting zone. In addition, there may be an optional third zone, the dispersive mixing zone, and the distributive mixing zone. In all cases, these parts should be thoroughly maintained and cleaned.