Layflat Behavior and Temperature Variation in Calendering: A Review

Calendering is the most efficient process for making large-volume, high- quality polymer sheets. The major challenge in the calendering process is to produce sheets with uniform gauge and no buckling, i.e., good layflatness. In this paper, the be havior of layflatness in calendering processing is reviewed to provide a basic understand ing of layflatness behavior. The basic processing parameters that control the layflatness are also identified. Observation by measuring the temperatures of the workpiece and calender rolls during operation is then conducted. Following a description of the sensor and proce dure used in measurement, the results and their relationship to layflatness are discussed. The measuring results are also used to assist in identifying the basic controlling parame ters of the layflat behavior. Finally this paper is concluded by recommendation of areas where further work is needed. A new approach to quantify the layflatness and a modifica tion to the current process for better control of the layflatness are also included in the recommendation.