Grinding is a process in which particles of solid material are reduced to the required size which is suitable for efficient application, absorbancy and utilization of the active substances. Grinding may be necessary for the resulting effect on the properties of raw materials which are essential for wet granulation and successive fluid-bed drying. Careful grinding is used for final treatment of granulates, namely for the modification of flow characteristics of raw materials before their final homogenization, tabletting or capsuling.