Screw barrel clearance is a critical factor in extrusion performance. It is the gap between the screw flight and the barrel inner surface.

When this clearance becomes too large due to wear, molten plastic can flow backward over the screw flights. The result may be lower output, unstable melt pressure and higher screw RPM.

Common warning signs include reduced kg/h, difficulty building pressure and declining product consistency.

For replacement projects, measuring only the screw diameter is not enough. The screw OD and barrel ID should both be checked at several positions.

The correct clearance depends on screw diameter, material, application and operating conditions.

If your extruder has lost output, send us the screw drawing, plastic material, screw diameter and current production data. We can evaluate the screw and barrel dimensions and manufacture a matched replacement set.