Roll Vibration in Roll Coating Nip
Vibration in roll coating nips has been previously shown to affect the surface quality of the coated product. A detailed vibration profile of the coating nip of the Monash Coater was obtained and is reported in the present research. The frequency spectrum was analysed with Fourier transformation and the results are discussed.
An unexpected peak of the recorded vibration amplitudes was observed at relatively high frequencies of approximately 50 kHz. These vibrations were correlated to relaxation motion in the rubber coating of the rolls. The nip pressure is suggested to lead to a forced dampened oscillation of the roll surface. These vibrations deliver additional kinetic energy to the coating nip and were shown to cause runnability problems such as coating colour misting.
Systematic studies of the vibration behaviour of a single coating roll were included, suggesting the rubber coating, material properties and geometry of the roll to affect the vibration properties.