单喷头多材料电流体动力喷射3D打印机理和规律的研究

多材料多尺度3D打印是当前增材制造的前沿、研究难点和亟待突破技术。针对目前3D打印面临两个挑战性难题：（1）多材料跨尺度复杂三维结构低成本制造；（2）基于多喷头或材料被动混合的多材料3D打印存在结构控制复杂、材料混合不均匀、效率低、成形材料受限问题。本项目提出一种单喷头多材料主动混合电流体动力喷射3D打印新工艺，旨在发展一种多材料多尺度3D打印新方法。基于课题组前期已有研究成果，项目重点开展单喷头多材料电流体动力喷射3D打印基础理论研究，揭示单喷头多材料电流体动力喷射3D打印成形机理、影响因素和规律。主要研究内容包括：（1）多材料主动混合作用机理及规律；（2）多场作用下多材料纳升/皮升微滴形成和演化机制，微滴精准按需沉积的影响因素和规律；（3）多材料电流体动力喷射3D打印表面/界面行为及调控机制；（4）实验平台搭建、工艺优化以及功能梯度材料/结构模型和变刚度模型等打印实验验证。

Multi-material and multi-scale 3D printing is new frontier in additive manufacturing. The emerging technique has shown great potential to implement the simultaneous and full control for fabricated objects including external geometry, internal architecture, functional surface, material composition and ratio as well as gradient distribution, feature size ranging from nano, micro, to marco-scale, embedded components and electro-circuit, etc. That paves the way and may result in great breakthrough in various applications, e.g., functional tissue and organ, functionally graded material/structure, wearable devices, soft robots, functionally embedded electronics, metamaterial, multi-functionality product, etc. However, there are two challenging issues for current 3D printing processes. One is how to fabricate the heterogeneous and hierarchical structured objects at low cost. The other is that multi-material 3D printing based on the multiple printheads and passive mixing methods has several problems including the complex structure and control, inhomogeneity of mixing multiple materials, low efficiency, limited printing materials. The proposal presents a multi-scale and multi-material 3D printing process with a single printhead. The overall objective of the project is to establish a novel multi-scale and multi-material 3D printing process. Based on the existing research results of applicants, the project focuses on the theoretical basis and key technologies regarding the proposed 3D printing process. It mainly includes following several aspects: (1) the mechanisms and law of the active mixing multi-material printhead; (2) the generation and evolution of nanoliter/ picolicer micro-droplet with multi-material under multi-field condition, the influencing factors and laws for the accurate and DOD deposition of micro-droplet; (3) the surface and interface behaviors and regulatory mechanism for multi-material electrohydrodynamic jet 3D printing; (4) experimental set-up construction, process optimization, and experimental verification for typical applications including variable stiffness models and functionally graded material/structures, etc.