Brookfield Rheometer explained
This apparatus measures flow behavior of low viscosity fluids by means of a rotating disc of defined dimensions. The resistance of the rotating disc is measured and is proportional to the liquids viscosity. Thixotropic, rheopectic, newtonian and non-newtonian flow behavior can be determined with this device. Viscosity data obtained with this method is used for determining the amount of spin finish needed to result in the desired effect.
Next to this, in depth spin finish optimization suited for your process uses this technology. The viscosity of spin finishes, for example, cannot be too high in order to be applicable.