Temperature Variation in Calendering and Its Relationship To Spc Analysis of Layflatness

Abstract

In calendering, the major challenge is to produce polymer sheets and films with uniform gauge and good layflatness. In this paper, the basic operating parameters which influence the product shape quality or layflatness are reviewed. Temperature sensors have been implemented in an industrial scale calendering line to measure the temperature of calender rolls and materials insitu, with the goal to provide a basis for identifying the causes of the layflat problem. The sensors and procedures adopted are described. The sensing results and their relationship to layflatness are also discussed. Some temperature irregularities have been found, and identified as major contribu tors to the layflat problem. This finding has been further confirmed by a Statis tical Process Control (SPC) study. In the SPC study, the sensing data have been analyzed, and a correlation between temperature distributions and layflat be havior of the final product has been found. An active control strategy inte grating the on-line sensing and SPC concept has then been developed to alleviate layflatness problems. Finally, this paper concludes by identifying those areas where further work is needed.