What Causes the Rubber Extruder Barrel to Move in An Eccentric Fashion?

The rubber extruder barrel is normally supported in some way by the frame on which the whole system is mounted. If the extruder barrel moves, and this can happen sometimes even when the barrel is supported, it can indicate that the extruder shaft is bent, the barrel is misaligned, or a combination of extruder configuration and recipe characteristics result in a product mass that is not fluid or flowable inside the barrel.

Bent shafts will cause the end of the extruder barrel to move in an eccentric fashion and this can be corrected by straightening the shaft or, in some severe cases, replacing the shaft. Proper alignment of the extruder barrel sections around the shaft will also reduce this movement. Barrel alignment techniques should be taught by a qualified service engineer experienced in the maintenance of the system.

Some recipes do not lose viscosity during the heating/hydrating processing steps normally present in a cooking extrusion environment. This fact, coupled with a configuration that utilizes a screw profile that may become unbalanced when extruding at certain operating parameters, can result in the extruder barrel moving in an eccentric motion.

If operation of an extruder that has severe eccentric movement in the barrel continues, fatigue may result in the shaft and barrel components which may lead to costly repairs and unscheduled down time.