Abstract
In the manufacturing process of glass fibers, the glass-fiber cake, in which the glass fibers are wound on a paper tube to form a cylindrical shape, sometimes collapses inwardly during the drying process in the hot air. In order to clarify the mechanism of this collapse, the water content, and the distributions of temperature and vapor pressure in a fiber layer of a model glass-fiber cake were measured in the drying process. As a result, the external pressure, which was caused by the steam pressure in the fiber layer, acting on the inner layer of the cake was attributed to the inward collapse of the cake.
