Experimental investigation of the drying process of water-based paints used in automotive industry

The objective of the government-funded research project “SiLat” (Simulation der instationären Lacktrocknung bei dreidimensionalen Objekten—simulation of paint drying processes on three-dimensionally shaped geometries) is the development of a CFD-software simulation add-on for the drying process of paints [11]. The software is intended to be used in the automotive industry to predict the intermediate drying process of water based paints on car bodies in continuous convective dryers. To validate the software, several laboratory scale experiments, using industrial water-based paint systems and a model base paint system applied on a sheet of metal, were carried out. Conditioned air was used for the drying process. The experimental setup was varied in three different ways: paint on a flat sheet was dried in impinging jet and parallel flow conditions. Furthermore, a Z-shaped sheet was dried during parallel flow conditions. Additional experiments were performed varying the flow parameters. During all experiments, the sheet temperature and weight of the painted sheet were monitored with a rate of 1 Hz. The evaporation of the organic solvents could be monitored using FTIR-spectroscopy. This contribution deals with the experimental investigations and simulation results, whereas the paint drying model is presented by Domnick et al. [5] in detail.