As the wood pellet mill equipment compresses the raw material into pellets some material is not compressed into pellets, this dust is referred to as fines. Fines are particles of material that failed to bind to the pellet during pellet formation; this could be due to lack of pressure in the wood pellet mill equipment or a lack of binding. If the pellets produced are not mechanically strong, as the pellets move and rub against other pellets and surfaces particles break away from the pellet, again these are described as fines. So the performance of the wood pellet mill equipment and the quality of the finished pellets affect the percentage of fines.
Pellets produced by wood pellet mill equipments are very strong with vertical pressure, but all pellets break fairly easily under horizontal pressure. Pellet breaking is not that important, but how the pellet breaks is. When horizontal pressure is applied to quality pellets the pellet should break cleanly. A poor quality pellet however under horizontal pressure will break into several pieces and produce many fine particles.
