ROLL DESIGN EFFECT ON NIP PRESSURE

摘要

The quality of reeling process is a key factor in achieving production efficiency, especially when machine speed and paper width continue to increase. For calendered and coated grades of paper the main problems are the formation of air entrapment, web instability and wrinkles. Nip pressure may be used as a tool for controlling the air entrapment as well as for limiting large wound on tension that would lead to yielding or wrinkling defects within the wound roll. In this paper nip pressure is studied as a function of geometrical and material parameters of the rolls in order to identify and quantify their individual and cumulative influence. For this purpose measurements with Tekscan's pressure-sensing technology and Fuji's colour-forming and developing films were performed together with finite element calculations. The results offer a better understanding of the connection of geometrical and material parameters to the quality of reeling process and can be used as practical guidelines for designing reeling rolls.