抄録
Various kinds of wound roll defects such as telescoping, dishing, starring, and wrinkles often appear in many manufacturing lines of web handling. In order to investigate how the dishing or telescoping is developed and to get fundamental knowledge of these roll defects, several web winding processes are simulated by using a simple three dimensional FEM model which is composed of an isotropic web and a rigid core. In the simulation, effects of core inclination, unbalanced web tension, and constraint of lateral displacement of the web end on both a lateral shift of web and an edge shape of wound roll are investigated. The results show that (1) when the web is wound around the inclined core, the web shifts at first to the side where the web becomes loose due to the core inclination, and then it returns almost to the original position, if the web end is constrained not to move in the lateral direction. As the results, edges of the wound roll have a curved shape instead of a flat plane. (2) When the web is wound under the condition of unbalanced tension distribution in the width direction, the web shifts at first to the side where the web tension is larger, and then it returns like the case of the inclined core, if the web end is constrained. But if the web end can move freely in the lateral direction, most part of the web are correctly wound in spite of the unbalanced tension condition and the edges of the wound roll become flat except a few outer layers of the roll. These tendencies of the web shift may hold good for any web with different length. Both the web shift and the roll edge shape described in the above can be explained by knowing the web deformation during winding and the normal entry law of the web. (3) The telescoping suddenly occurs when an axial load acting on a wound roll increases gradually. The axial load where the telescoping occurs gets larger as a winding tension or a friction coefficient increases.
