The pressure distribution in nips of systems of flexible rubber-covered rollers

In this paper, a simulation tool is presented to support the design process of systems of flexible, rubber-covered rollers. A mathematical model is developed to determine the axial pressure variations in the nips of these systems. In the model the indentations of the rubber layers are coupled to the deflections of the rollers due to bending. The model is generic in the sense that the number of rollers in the system is not fixed, and rollers may have different lengths and be located asymmetrically with respect to each other. The rollers bend due to linear conditions applied at arbitrary positions along the roller axes. The rollers may have a surface profile and the rubber layer thicknesses may vary. In each nip paper can be present, located at any position. By an efficient numerical algorithm that solves the model, the effect of bending on the nip pressure distribution is determined. Crowning, use of an additional support roller, and internal bearings are examples shown as means to achieve a uniform pressure distribution.

► We model pressure variations in nips of systems of flexible rubber-covered rollers.
► Rubber indentations are coupled to bending deflections of the roller cores.
► The model is generic and can deal paper in nips and crowned rollers.
► Our solution approach indicates existence of a solution; simulation times are seconds.
► Crowning, support rollers and internal bearings yield a uniform pressure distribution.