Li Wang,Yu Luo,Zhiqiang Yang,Wanjing Dai,Xiaoyang Liu,Jingyuan Yang,Bingheng Lu,Lijia Chen
Nowadays, along with the demand for new technologies and new materials, a revolution in 3D printing technology is emerging. In recent years, stereolithography 3D printing has been widely used in both academia and industry, due to its fast forming speed, high precision, and low-cost advantages. The continuous liquid interface production technology has made the printing speed even faster. However, the process of resin refilling constrains the printing speed and the printing capabilities of such technologies, since only hollow structures can be fabricated. In this study, a nano-textured hydrophobic PDMS contacting layer and an oxygen-permeable membrane were bonded together as the functional release film. The oxygen inhibition layer was successfully maintained by the molecular oxygen permeated through the composite release film, achieving rapid stereolithography, and key factors that affecting resin refilling are selectively studied by the orthogonal experiment. Crucially, according to the simulation and experimental results, the adoption of the hydrophobic nano-texture not only increased the refilling speed of the resin by two times and reduced the printing time by nearly 25%, but also improved the printing reliability by reducing the vacuum (negative pressure) caused by the original slow refilling speed. Additionally, optical simulations also demonstrated that the nano-texture would not influence the curing effect of the resin. This work proposed a promising strategy for rapid stereolithography of 3D models containing larger cross-sectional areas.
A series of fluorine-silicon block urethane acrylates (PSi-FMPG-IPDI-HEMA) were synthesized from hydroxypropyl-terminated polysiloxane (PSi), newly-prepared fluorodiol (FMPG), isophorone diisocyanate (IPDI) and hydroxyethyl methacrylate (HEMA). Their molecular structures were characterized by Fourier transform infrared and gel permeation chromatography. The compatibility of the oligomers with HFMA was validated using UV–vis transmittance analysis. The thermal stability, water and chemical resistance, contact angles and anti-adhesive performance of the films were measured. It was found all the films had good thermal properties, and excellent water and chemical resistance. The FMPG content affected the surface energy and anti-adhesive performance of the films. The films with more FMPG presented lower surface energy, lower peel strength, and higher residual adhesion. More importantly, the release films designed based on the fluorine-silicon block urethane acrylates had tremendous application potential.
Vat photopolymerization (VPP) is one of the convenient methods to create high-precision parts; however, due to the significant adhesion between the cured layer of the photopolymer resin and the release film, the currently prevalent VPP equipment is less productive and thus challenging in achieving production on a large scale. To tackle the issues above, a facile method is utilised to produce a transparent film capable of effectively resisting the photopolymer resin. Such film is achieved by incorporating micron-nanometre layered rough features and low surface energy materials onto the surface of quartz glass. It allows innovative applications in speedy VPP processes, achieving a printing speed of up to 323 mm/h in an LCD (Liquid Crystal Display) 3D printer while maintaining sound accuracy, exceptional durability and fair applicability, thanks to the features of the prepared film. The presented approach provides new perspectives into the production and application of VPP technology.
危险品化学品经营许可证（带存储）