Optimization of Low One-Photon Polymerization for Hydrostatic 3D Printing of Silicone Material

This study investigated the parameter optimization of low one-photon polymerization in hydrostatic 3D printing (H3P). H3P produces 3D structures in a hydrostatic condition with minimum or no physical supports, used particularly for soft materials that typically require substantial supports to hold the position and shape in conventional 3D printing methods. H3P allows for “in-liquid” polymerization to happen by low one-photon polymerization (LOPP) to cure the silicone at the focusing spot inside of the resin. With the selected UV-curable silicone, different wavelengths, light intensities, and exposure times were investigated to achieve an ideal LOPP. The ideal LOPP should have a wide time window to precisely control the polymerization size and produce a consistent geometry. This is largely dependent on the light wavelength and then the intensity. In this study, the wavelength of 387 nm with the absorbance rate of 0.008 was found the optimal setting for the selected silicone among 365 nm (0.051 absorbance rate) and 405 nm (nearly 0 absorbance rate) wavelengths. The results showed that the parameters for LOPP are very selective.Mechanical Engineerin