Simulations and practical experience in the optimisation of paint film levelling

The market appeal of consumer and technological products is strongly influenced by the appearance of the paint layer (""orange peel effect"") which arises from a complex interplay of a variety of different physical processes, e.g. the statistical superposition of droplets during the spraying process or the partial mapping of the substrate structure onto the paint film by different mechanisms. Numerical 3D and 2D simulation models are presented that incorporate all the relevant processes for the paint film structure formation after spray application. Simulation examples illustrate the influence of viscosity, the shape of droplet size distribution and skin formation during the evaporation phase. The simulations generate fundamental insights into the structure formation. This knowledge is used to systematically optimise the appearance and explain the results of a statistical design of experiment in the lab.