VARIABILITY OF DRY FILM THICKNESS OF A COATING APPLIED BY ROLLER COATER ON WOOD IN A REAL INDUSTRIAL PROCESS

This study investigates variation in the dry film thickness (DFT) of a coating applied by roller coater on the surface of wood in real industrial conditions on a UV finishing line. It was examined how DFT is influenced by the temperature of the liquid top coating, the position of the sample on the conveyor, and the position of the measurement point along the length of the sample. The three-way interaction between the temperature of the liquid top coating, position on the conveyor and position along the sample did not have a statistically significant impact on DFT. However, an increase in the temperature of the liquid top coating (from 24.1 to 24.8 degrees C) caused a decrease in the viscosity of the coating and a significant reduction in DFT when samples were positioned closer to the coating supply hose or in the middle of the conveyor. When the temperature of the liquid top coating was lower, the variation in DFT at different positions across the conveyor was not significant. A higher temperature of liquid top coating led to significantly smaller DFT for samples closer to the supply hose and in the middle, compared with those further from the supply hose. It was also found that DFT was greater at the forward end then at the back end of sample.