Light Transmittance of Transparent 3D Printing Resins

Abstract

Many manufacturers offer resins that are advertised as transparent. Transparent 3D printed parts are not only visually attractive, but this feature is often required for practical use, for example, in optical parts. The manufacturers themselves point out that achieving optimal light transmittance requires appropriate post-processing. In this study, we evaluate the transparency of 10 types of commercial 3D printing resins by measuring their light transmittance. Each resin was used to print sample tiles that were post-processed in eight different ways. The light transmittance of each sample was then measured using a commercial spectrophotometer to determine which post-processing methods yielded the best transmittance properties for flat objects printed using different resins. We also evaluate the impact of post-processing methods on the chromaticity measures and surface roughness of the sample tiles. Finally, we assess the effect of samples' exposure to direct sunlight by comparing light transmittance measurements taken at two different time points. Our results show that to ensure the highest level of transparency, it is crucial to coat the parts with a layer of clear varnish. For such samples, transmittance averages nearly 24% higher than for the unvarnished ones.