How exactly does the colloid mill rotor stator assembly generate shear during processing?

The colloid mill rotor stator assembly generates shear because the rotor spins at high speed only a fraction of a millimeter away from the stationary stator surface. This creates an extremely steep velocity gradient across the thin fluid film in the gap, subjecting suspended particles or droplets to strong shear and elongational stresses that mechanically break them apart into much finer, more uniformly sized fractions.