Pressroom Runnability : A Comprehensive Analysis of Press Room and Mill Database

Résumé fourni par la source

Web break is an important runnability issue in the pressrooms. However, web breaks are rare events. Performance statistics for a large number of rolls are required to determine the causes of runnability problems with a reasonable level of confidence. To provide better insight into the main causes of web breaks, we analyzed seven pressroom/mill databases of sufficient size to produce reliable runnability statistics. The statistical association between strength properties (average) and break rate was examined using a Chi Square analysis method. We found that the statistical association between strength properties (average) and break rate varied considerably from one pressroom to the other (or from one mill to the other), depending on the pressroom operation (the variations of tension) and the quality of data from mills. However, among different strength properties, MD tensile strength has been most consistently associated with the break rate. CD tear strength did not consistently predict the runnability. We also found that strength uniformity had a significant impact on pressroom performance. Lastly, the pressroom data consistently showed that typical, macroscopic defects are now minority causes for web breaks and the majority of breaks are press-related or unknown.

Ce résumé expose les affirmations des auteurs. BNTIC ne l’interprète pas comme une validation indépendante des résultats.