Optimization of taper winding tension in roll-to-roll web systems

Winding is an integral operation in almost every roll-to-roll system and the center-wound roll is one of the suitable and general schemes in a winding mechanism. The quality and performance of a center-wound roll are known to be related to the winding tension. In this paper, a novel optimization design method for winding tension using a special network structure is proposed. Firstly, based on the elasticity theory, the correlations between winding tension in the winding section and hoop stress distribution within a center-wound roll are analyzed. In addition, an analysis model for the residual stress due to the winding tension profile is developed. Then, according to the analysis model, the special network structure with back propagation training is developed to minimize the error of lateral residual stress, namely isostress-distribution. Finally, the experimental prototype of a roll-to-roll packaging system for glass-fiber fabric that can measure and control the winding tension is described, and actual experiments were carried out. Results show that the proposed method is very useful for determining the desirable taper-tension profile during the winding process and preventing defects of the center-wound roll.