ERI: Additive Manufacturing of Polymer-Matrix Composites with High Concentration of Silicon-Carbide Particles by Novel Digital Light Projection

增材制造（AM）为制造复杂结构的陶瓷-聚合物复合材料提供了一个通用的平台。在过去的二十年里，各种创新的增材制造工艺已经成功地用于陶瓷聚合物3D打印。特别是，基于数字光投影（DLP）的方法使陶瓷-聚合物复合材料的复杂结构的直接数字化制造成为可能。尽管具有潜在的优势，但目前的DLP AM在打印具有高浓度陶瓷颗粒的复合材料方面存在困难，例如碳化硅（SiC），希望增强打印部件的功能。挑战在于颗粒-聚合物相互作用导致的粘度增加，从而对原料流动产生高阻力。该工程研究启动（ERI）奖支持基础研究，以了解高粘性陶瓷含光聚合物印刷背后的物理原理。该研究涉及物理学、材料科学、表面工程和制造技术的多学科整合。该项目将产生强大的技术和经济影响，以高效率和成本效益的方式简化具有复杂几何形状的部件的生产，例如用于脚手架和热交换器的陀螺结构，同时确保零件尺寸和微观结构的质量。此外，该项目将让少数民族学生参与研究和教学，从而提高STEM教育和他们在先进制造业劳动力中的代表性。该ERI项目的目标是了解使用高粘性陶瓷悬浊液进行复杂形状零件的3D数字光打印的两个主要障碍（即高分离力和光散射）背后的基本原理。该项目将首先通过“树脂补充”机制解决高分离力的挑战，通过将氧气渗透到系统中，引入微纹理空气通道来加速树脂重新涂层，减少打印部件与构建窗口之间的分离力。其次，建立了一种动态掩模图像投影策略，并采用该策略将光散射和不希望的照片图案在打印部件内的影响降到最低。这将使具有复杂几何形状和精确微特征的3D聚合物陶瓷部件的高精度和高速制造成为可能。如果成功，该项目将对将表面工程技术应用于透氧空气通道产生变革性影响，从而实现自下而上逐层3D打印具有增强机械性能的sic聚合物复合材料结构。该研究还将推进使用动态掩模图像来补偿光散射对固化结果的影响的新型投影的知识。因此，将开发一种新技术，以避免高粘度陶瓷印刷中的固化缺陷或故障，并能够生产使用现有系统难以制造的复杂几何形状。该奖项反映了美国国家科学基金会的法定使命，并通过使用基金会的知识价值和更广泛的影响审查标准进行评估，被认为值得支持。

Additive manufacturing (AM) offers a versatile platform for fabricating ceramic-polymer composites of complex structures. Over the last two decades, various innovative AM processes have been successfully developed for ceramic-polymer 3D printing. Especially, methods based on digital light projection (DLP) enable the direct digital fabrication of intricate structures made of ceramic-polymer composites. Despite potential advantages, current DLP AM have difficulty in printing composites with a high concentration of ceramic particles, e.g., silicon carbide (SiC), desired to enhance the functionality of printed parts. The challenge lies upon the increased viscosity resulted from the particle-polymer interactions, causing high resistance to the feedstock flow. This Engineering Research Initiation (ERI) award supports fundamental research to understand the physics behind printing of ceramic-included photopolymers that are highly viscous. The research involves multi-disciplinary integration of physics, materials science, surface engineering, and manufacturing technology. The project will have strong technological and economic impacts by streamlining production of components with complex geometries, e.g., gyroid structures, for scaffolding and heat exchangers, in an efficient and cost-effective manner, while ensuring the quality in part dimensions as well as microstructures. Moreover, this project will involve minority students in research and teaching, thus, enhancing the STEM education and their representation in advanced manufacturing workforce.The goal of this ERI project is to understand the fundamentals behind two major roadblocks, namely, high separation forces and light scattering, in 3D digital-light printing of complex-shaped parts using highly viscous ceramic suspensions. The project will first address the challenge of high separation forces through the “resin replenishment” mechanism by integrating oxygen permeability into the system, introducing micro-textured air channels to accelerate the resin re-coating and reduce the separation force between the printed part and the build window. Secondly, a dynamic mask image projection strategy will be modeled and employed to minimize the effect of light scattering and undesired photo patterns within the printed part. This will enable high-accuracy and high-speed fabrications of 3D polymer-ceramic parts with complex geometry and precise micro-features. If successful, the project will make a transformative impact of applying surface engineering techniques to oxygen permeable air channels for bottom-up layer-by-layer 3D printing of SiC-polymer composite structures with enhanced mechanical properties. The research will also advance the knowledge of novel projection using dynamic mask images to compensate for the influence of light scattering on curing results. Accordingly, a new technology will be developed to avoid curing defects or failures in high-viscosity ceramic printing and enable producing complex geometries that are challenging to make using existing systems.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.