Study on impact of UV curing process of digital light processing 3-D printer on the mechanical properties and dimensional accuracies

Abstract

In the last decade, there has been an exponential increase of the scientific interest for smart additive manufacturing (AM) technology. Among the different AM techniques, the most commonly applied processes are digital light processing (DLP). DLP is a laser-based process that works with photopolymer resins, which react with the ultraviolet (UV) and is cured to form a solid in a very precise way to produce parts with high dimensional accuracy. However, because of the scattering effect when UV light passes through the transparent vat and different polymerization characteristics and curing depth of photopolymer resins, there are lots of parameters of DLP printers need to be optimized.
Among these, exposure time affects the quality of the 3D printed specimen. If it is not optimized, it brings about problems such as poor mechanical properties and poor dimensional accuracy. Therefore, this study examined
optimal exposure time. With a same specimen and layer thickness, the photopolymer resin was exposed to the UV light in different times to evaluate the influence of it. The UV mercury lamp, 240 W and wavelength of 385-650nm is used. To investigate the effect of exposure time on the mechanical strength, the tensile strength and young’s modulus were experimentally determined using universal material test machine.