Film thickness fluctuation in the longitudinal direction is difficult to see. Bearing damage or concentricity inaccuracies lead to fluctuations in the longitudinal thickness.
The determination of impending bearing damage, run-out errors of individual rollers and for preventive maintenance offers potential.
Our method is a thickness measurement over the length of the film, taking into account individual roll diameters and speeds. Fourier analysis is used to determine the thickness variation.
Thickness variation = f (speed, roll diameter)