Water-based coatings for 3D printed parts

Three-dimensional (3D) printing or additive manufacturing is an emerging technology that enables the exploration of new ideas and designs. The process converts a 3D digital model into a 3D object, allowing end users to hold and easily visualize their designs. Since 3D printed parts are built through layer-by-layer deposition, they exhibit limited surface smoothness and surface quality. By applying water-based coatings onto 3D printed parts, surface quality can be improved by reducing surface roughness and by sealing surface gaps without deforming the parts themselves. In this study, water-based coatings were applied to 3D printed parts using a computer-controlled dip coater. Surface profiles of 3D printed parts before and after dip coating were measured using a profilometer and parts were examined with optical microscopy. Two commercial water-based coating systems were evaluated, and the effect of coating speed, drying conditions, and number of coated layers on surface roughness of 3D printed parts was studied. The effect of printing with different print tips and in different orientations on surface roughness before and after coating was also studied. Coating liquids with higher solids loading were found to be most effective at smoothing or planarizing the 3D printed part surface.