Ball Mill is one type of milling machine which is used to mill or grind the materials such as large sized particles either active drug ingredients or excipient and agglomerates.
Ball mill consists of horizontal rotating cylindrical vessel or shell with the length slightly greater than its diameter which is mounted on a metallic frame in such a way that it can be rotated on its longitudinal axis. The axis of the shell or vessel may be either horizontal or at a small angle to the horizontal. The cylindrical vessel contains balls that occupy 30-50% of the mill volume.
The grinding media is the balls which may be made up of stainless steel. The ball size depends upon the feed and the dia of the mill.