PET is a material which everyone immediately associates: with blow-moulded bottles for soft drinks and mineral water. Due to its outstanding material properties and, not least due to failing raw material prices, PET is also gaining increasing importance in other sectors. PET film, in particular, which has low permeability to water vapour, oxygen and flavourings, in addition to good temperature resistance, is becoming increasingly popular. PET film is primarily produced by the polishing process, which has to be customised in line with the particular demands of the material. For this reason, apart from the right choice of extrusion line, the construction of the polishing rolls (Fig.1) is especially important.