AS compared to the four common principles of reduction, i.e., grinding, compression, impact and shearing, which do not produce controlled size machine utilizes the principle of variable force swing hammer blades having both knife and impact edges rotating reduction, this with a carefully selected screen to control size reduction.

Flow path of material in vertical rotor machine is streamlined. During comminating, material entering the chamber travels to the periphery and passes through the screen tangentially and radially avoiding chocking and temperature rise.