Bearing assemblies in a pellet mill support the rotating shafts of the main drive, die ring and roll assemblies, allowing smooth rotation under the heavy radial and axial loads generated during pelleting while minimizing friction and wear. Because pellet mills operate continuously under high load, with significant forces transmitted through the die and roll assembly during compression, bearing selection, sizing and lubrication are critical to reliable operation.

Main shaft bearings typically must be rated for both the mechanical load of driving the die and the thermal conditions generated by the pelleting process itself, with many designs incorporating dedicated cooling or lubrication systems to manage heat buildup and extend bearing service life.

Roller bearings, rather than simple sleeve or plain bearings, are typically specified for the main rotating assemblies in a pellet mill given the combination of high radial load and the need for low-friction, reliable continuous-duty operation; specific bearing types (such as spherical or tapered roller bearings) are selected based on the particular load characteristics — radial, axial or combined — present at each bearing location within the machine.

Lubrication system design varies between manual periodic greasing on smaller machines and automated centralized lubrication systems on larger or higher-duty pellet mills, with automated systems generally preferred where consistent lubrication interval compliance is difficult to guarantee through manual procedures alone, given the consequences of bearing lubrication lapses in continuous high-load service.

Bearing failure is one of the more serious unplanned maintenance events in a feed mill, often resulting in extended downtime, so most operations follow scheduled lubrication intervals and monitor bearing temperature and vibration as part of routine condition monitoring to catch developing issues before catastrophic failure occurs.

Vibration analysis, in particular, has become a widely used predictive maintenance tool for pellet mill bearings, since developing bearing defects typically produce characteristic vibration signatures well before the bearing reaches a point of imminent failure, allowing planned replacement during a scheduled maintenance window rather than an unplanned breakdown during production.