连续高速面约束光固化成型固化层-基底界面粘附行为调控新方法

In view of production rate limitation caused by the technics reliability due to adhesion at the fluid-solid interface and the restriction in mass manufacturing due to high cost in continuous fast constrained-surface projection based stereolithography process, a novel method is proposed, in which, polymerization inhibition zone (PIZ) is implemented at low cost and the liquid material flow drag is reduced through modulating the substrate surface wettability resulting in slip at the interface between liquid material and substrate. The mechanism of the influence of surface nanostructures on the contacting state and the flow drag at the interface is investigated, which results in the theory foundation for surface nanostructures planning. The influence law of the composite path for light/gas transmission of the constrained substrate with mutimedia and complex interface on mass transfer of the polymerization inhibition gas and light energy transportation is investigated and then mechanism of the influence of composite path for light/gas transmission on the PIZ formation is revealed, based on which, the requirements on the geometry characteristics of nanostructure and pore on the substrate is proposed. The controllable mass fabrication technics for nanostructures on soft thin film surface with prescribed geometrical size and morphology is investigated and the foundation for engineering application will be built. The nanostructure geometry and pore morphology effects on the interface slip and PIZ property is highlighted, based on which, the design rules of the morphology in micro-scale meeting the requirements for drag reduction and PIZ formation are proposed and the regulation method for forming stable PIZ is presented. Implementation of this project will resolve the problem of the production rate restriction due to technics reliability caused by interface adhesion and hence promote the application of stereolithography advancing forward to mass manufacturing of functional parts from rapid prototyping.

针对连续高速面约束光固化成型中界面粘附引起的工艺可靠性制约打印速度提高以及实现大批量生产成本瓶颈问题，提出一种以低成本实现阻聚层并通过调控固液界面浸润特性减小流动粘附阻力的新方法。通过研究纳米结构特征影响打印材料-基底界面接触浸润特性从而影响流动阻力的机理，为表面微观结构的设计提供理论依据；研究以多介质和复杂界面为特征的约束基底光/气混合传输路径影响阻聚气体传质及光能量传输从而影响阻聚层形成的机理，提出实现阻聚层稳定性对基底微观结构和孔隙特征的要求；研究柔性膜表面规定尺寸纳米结构大面积可控制备工艺，为工程化应用奠定基础。项目重点揭示纳米结构及孔隙特征与界面浸润滑移及阻聚层特性的相关性，提出满足减阻及阻聚层形成的微观结构特征设计准则及实现稳定阻聚区的调控方法。本项目的研究，将解决成型效率与工艺可靠性之间相互制约的难题，从而促进光固化成型的应用由产品原型快速制造向功能零件大规模直接制造的转变。

3D打印技术由产品原型快速制造向功能零件大规模直接制造的发展趋势对打印效率提出了更高的要求，连续液面成型利用氧阻聚反应形成的阻聚区使分离力显著减小，从而显著提高了打印速度，然而透氧窗基底的大变形和高成本是规模化应用的障碍。本项目提出一种低成本实现阻聚区的成型室约束基底方案，并围绕阻聚区影响因素的作用机制、树脂在微间隙填充流动阻力的机理以及织构化柔性膜制备工艺等设计和制备约束基底的基础问题展开研究，具体工作及结论包括：采用时域有限差分法对约束基底微观特征影响透光性的规律进行了系统研究，给出了满足透光性的基底微观特征设计依据；通过数值模拟结合实验测量研究了基底微孔面积率、孔径及膜厚等界面特征对成型区阻聚气体分布的影响，得到了基底微观特征影响透氧性的规律；建立了多物理场计算模型，该模型综合考虑了光致聚合反应动力学、氧气固化抑制、氧气渗透传质以及光传输，研究得到了工艺参数及材料特性影响氧阻聚区的规律，为阻聚区的调控提供了理论依据。为了提高膜的透氧性从而拓宽阻聚区的调控空间，通过分子动力学模拟研究了PDMS膜成膜工艺要素对氧气扩散过程的影响规律，给出了PDMS膜制备工艺中质量比、交联温度、交联度的优化参数。建立了考虑柔性膜变形的流固耦合计算模型，采用变形几何及移动边界仿真技术研究了不同工艺参数条件下流场的负压分布，得到了界面滑移等工艺因素影响负压吸附力的规律。基于相场法研究了液态树脂在织构化基底表面的填充流动过程的流体动力学特性，初步给出了满足滑移要求的织构参数。基于双线性内聚本构模型对固化层自基底的分离过程进行了数值模拟和试验研究，探究了不同微观结构特征对固化层剥离过程断裂失效的影响机理和规律。探索了纳米二氧化硅小球制备、纳米小球单层密排及ICP转移刻蚀以及硅微加工制备微纳结构模具的工艺，通过微模铸工艺制备了表面微纳织构化的防粘附功能膜。