PDF TP1: Spray Drying, Milling and Granulometry (Responsible: Azade ... EPFL
To reduce wear on the bearings, the load must completely cover the milling ball charge ( the powder to be milled). In general, it will represent a volume corresponding to approximately 25% of the volume of the jar. If the load to be ground is a dry powder, the beads volume can be adjusted after a few minutes of milling or vibration.