Surface coating is a central step in the production of floor coverings (regardless of the type): the coating must withstand high stresses, is an important design feature and has a decisive influence on the properties of the floor covering. Common coating agents for floors are varnish, oil and wax.
The coating material also has an influence on the course of the production process: In order to achieve a high precision of the tongue and groove joint or click profile, surfaces with a large layer thickness are always applied before profiling. This is particularly the case with the UV coatings frequently used today. The coating is then followed by profiling; afterwards, the edges and, above all, any chamfers must be recoated.
The situation is different with more sensitive surfaces such as those made of natural oil: these do not form a thick layer, but penetrate into the wood surface. Profiling after oiling would damage the surface, as the transport chains of the double-end tenoner would leave behind changes in gloss. Therefore, in this case, profiling is carried out first and then the surface coating is applied.
The coating process itself consists of several parts. Coating systems consisting of primer and top coat are often used. If a varnish/lacquer is involved, both the base coat and the top coat are usually built up in several layers. The entire surface coating can therefore have five or more layers.
The coating agent is applied in liquid form by a roller coater. Coating machines are used less frequently. The floor elements pass the machine in a continuous flow. The lacquer, oil or wax must then dry. To shorten the drying time, drying systems are often used that work with heat radiation, hot air or UV radiation.