Air Knife Coating Head Paper Coating Machine

With knife systems, the coating paste is applied onto the carrier or the substrate with a knife or blade. Depending on the desired effect to the knife is countered by a roller, platen or nothing at all; thereby roller knives, platen knives and air knives are distinguished. The knife bar of modern coating plant is equipped with several coating knives and is changeable according to the revolver principle. This facilitates a quick change of the knives, especially of the roller and the air knife. All application systems are equipped with either manually or powered adjustable side scrapers.

In some cases, the side scrapers are completed to a closed paste basin with a front plate, which is necessary especially when low-viscous coating pastes are concerned. Depending on the thickness of the coat to be applied, on the way of the knife's configuration and the viscosity of the paste, knives of different profiles are used.

With knives, the thickness of the coat is defined by:

• Distance between knife and substrate.
• Kind of the substrate to be coated.
• Kind and form of the knives.
• Angle of the knife.
• Position of the knife.
• The viscosity of the paste.
• Speed of the web.