Roll Bouncing, 1996 Finishing and Converting Conference Proceedings

Alexis Olshansky

Beloit Lenox

In Finishing, a severe vibration of paper rolls on a two-drum winder that culminates in a single roll or a whole set coming out of the drum pocket, is called roll bouncing or roll throwout. The phenomenon, although known for a long time, is not very well understood in the industry. Because of its complexity and the many different causes of roll vibration and throwouts, it’s very difficult to exactly identify the root causes and to find solutions to them. This paper describes and explains the mechanism of roll bouncing, the most common causes of the phenomenon and the many known solutions to the problem. In addition, a framework of troubleshooting is provided to assist mill personnel in determining the cause or causes of vibration and in reducing or eliminating them. This paper is based on a study published by the author in 1993. It is expanded to include new technical material and a more complete treatment of the troubleshooting process, Winder vibration can be considered a part of this discussion, but the author has consciously kept this other important subject out this paper. Here we look at the phenomenon from an operating point of view. Only if it is established in the troubleshooting procedure that the winder is possibly at fault, there is a recommendation to bring in vibration analyzing equipment and find out what on the winder either causes vibration or vibrates in resonance with any of the forcing frequencies. This paper purposefully concentrates only on paper roll vibration and on how this relates to winder runnability and roll quality. Winder vibration is a different subject and will be dealt with separately.