Calendering

Calendering is a method for producing plastic sheet and film. A heated, softened, plastic is forced between two heated rollers (“nip” rollers), with fixed spacing. The rollers form the plastic into a thick, continuous sheet. Additional rollers reduce the thickness and, if wanted, emboss the sheet. The sheet may be further reduced in thickness by stretching it. The process is used to make various sheet plastic components such as flooring and tape, and to provide material for further operations. Sheet thickness ranges from 0.002 to 0.060 in (0.05 to 1.5 mm). ABS and PVC are the most frequently processed plastics. Upholstery sheet, rainwear, shower curtains, and tape are made with the process. By calendering two sheets of plastic with one or more layers of paper or other materials, such objects as credit cards, wallpaper, and playing cards can be made. Fig. 4J illustrates the calendering operation.

Fig. 4J Forming plastic film by calendering.