A novel method for improving surface finish of stereolithography apparatus

Stereolithography apparatus (SLA) is one of the most famous and versatile additive manufacturing techniques and has been widely used in many industrial fields. However, the surface quality of SLA parts is unsatisfactory for the precise parts due to stair stepping caused by the layered manufacturing process. In this study, the stair stepping of SLA parts was relieved by ultrahigh pressure atomizing coating with the polyethylene wax emulsion using a group of optimum coating parameters. The experimental results showed that polyethylene wax film with the thickness less than 0.1 mm bonded to the SLA parts adequately and the surface roughness of the SLA parts can be significantly reduced; the Ra of SLA parts was decreased to less than 2.5 μm. This method can be applied to improve both the outer surface and the inner surface of complex SLA parts with good dimensional accuracy and no damage to SLA parts, implying potential for fabrication of precise components. Expected advantages of this method include economical, operator-friendly, and time-saving for the manufacturers.