Cutter mill is a size reduction equipment consisting of a series of uniformly spaced knives (2 to 12 in number) attached to a horizontal rotor (rotating knives) which act against a series of stationary knives attached to the mill casing. The bottom of the mill has a screen attached to control the residence time of the particles inside the mill head.
Size reduction process involves successive mechanical sheering of the feed material with the help of sharp knife. Cutter mills produce coarse particles from
1. Dried granulations before tableting and
2. Fibrous crude medicinal/roots, barks prior to extraction
Particles size are determined by
a. Rotor size
b. The gap between the two (2) sets of knives
Although cutter mill may differ from one another in whether the knives are movable or fixed and in classifier’s configuration, two cutting mill subclasses have been identified:
1. Double runner disc mill
2. Single runner disc mill
1. It is used for milling tough materials
2. It is used to mill fibrous materials prior to extraction
3. It is also used to produce coarse particles from dried granulations before tableting.
1. It is the best option of size reduction when impaction, attrition, or compaction type milling is not effective especially for tough, fibrous, or resilient materials.
2. It is easy to install, operate, and maintain.
3. The equipment is not expensive
1. Cutter mill is not suitable for most pharmaceutical applications due to the formation of wide particle size.
2. It is not easy to clean after use.