Calendering Compounding Systems

Calendering is used for making foils/film/sheet out of plastics such as PE, PET or rigid PVC, as well as rubber, metal and paper. A calender comprises several heated rolls made of polished steel or chilled cast iron. Fed through the gaps, or nips, between them is a material such as pre-plastified compound from a BUSS compounding system. Calendering fully homogenizes the material and plastifies it to the desired thickness. After calendering compounding, the product is consolidated on cooling rolls. There is a difference between melt calendering for feedstock foils, and lamination calendering such as for coated textile conveyor belts. Calendering is also used for embossing, smoothing, compressing or satinizing, as well as for consolidating polymer fibres into nonwoven fabrics. Calender types are designated L, F, I or Z according to the arrangement of the various rolls.