Zhang Yu, Wu Lei, Zou Miaomiao, Zhang Lidian, Song Yanlin
Key Laboratory of Green Printing, Beijing National Laboratory for Molecular Sciences (BNLMS), Institute of Chemistry, Chinese Academy of Sciences, Beijing, 100190, P. R. China.
University of Chinese Academy of Sciences, Beijing, 100049, P. R. China.
Adv Mater. 2022 Jan;34(4):e2107249. doi: 10.1002/adma.202107249. Epub 2021 Dec 2.
3D printing has been considered as a sustainable method to construct complicated 3D structures. However, the step effect induced by the traditional point-by-point or layer-by-layer additive manufacturing mode inevitably occurs and remains an obstacle to realizing the smoothness and uniformity of 3D samples. Here, a continuous liquid film confined 3D printing strategy is proposed to fabricate high-precision 3D structures based on the Digital Light Processing (DLP) technology. With the control of the confinement of the liquid-solid interface and the continuous printing mode, liquid film adhering to the cured structure is sucked into the cured layer structures with excess resin adhering to the cured structure scraping off, where the step effect is eliminated and post-washing is avoided. The morphology and dimension of the confined liquid film can be well regulated by ink properties and printing parameters to optimize the surface smoothness and printing fidelity. In addition, heat accumulation and thermal diffusion are also suppressed, ensuring the long-term printing stability. A centimeter-scale contact lens structure with central thickness of ≈135 µm comparable to commercial ones can be printed, which possesses extreme smoothness (sub 1.3 nm), homogeneous mechanical characteristic, biocompatibility, and high optical properties with imaging resolution of up to 228.1 lp mm .
3D打印被认为是构建复杂3D结构的一种可持续方法。然而，传统的逐点或逐层增材制造模式所引发的台阶效应不可避免地会出现，并且仍然是实现3D样品的平滑度和均匀性的障碍。在此，提出了一种基于数字光处理（DLP）技术的连续液膜受限3D打印策略，以制造高精度3D结构。通过控制液-固界面的限制和连续打印模式，附着在固化结构上的液膜会被吸入固化层结构中，同时刮去附着在固化结构上的多余树脂，从而消除台阶效应并避免后清洗。受限液膜的形态和尺寸可以通过墨水特性和打印参数得到很好的调节，以优化表面平滑度和打印保真度。此外，热积累和热扩散也受到抑制，确保了长期打印稳定性。可以打印出中心厚度约为135 µm、与商业产品相当的厘米级隐形眼镜结构，该结构具有极高的平滑度（低于1.3 nm）、均匀的机械特性、生物相容性以及高达228.1 lp mm的成像分辨率的高光学性能。
