Session: 16-01-01: Poster Session: NSF-Funded Research (Grad & Undergrad)

Paper Number: 92021

92021 - Multi-Stage Additive Manufacturing for Multi-Scale Porous Ceramics 

As porous structures find more and more applications across many industries, a generic and cost-effective additive manufacturing technique for fabricating porous structures is highly desirable. Numerous biological creatures have multi-scale (combined nano-, micro, and macro-) porous networks which undergo successive evolutions. Such multi-scale porous structure integrates large surface area, lightweight, and high adsorption capacity. Consequently, manufacturing the functional nature-inspired multi-scale porous structures lies at the heart of research on energy conversion, biomedical implantation, environmental protection, etc.

Main challenges in additive manufacturing for multi-scale porous structures include printing resolution, porosity control, cost-effectiveness, scalability, etc. (i) Despite the fact that the resolution of the common AM technologies has been continuously improved in recent years, a bottleneck appears at the submicron scale. Both the lateral resolution and vertical resolution are limited by the nature of the digitalized manufacturing process of AM. (ii) Realizing complex functionalities in porous structures depends on the well-ordered, multi-scale structure. Using AM techniques alone has challenges to fabricating a combined micron-scale and nano-scale pores, which hinder the porosity control and arrangement, and consequently limit the performance of the AM specimen. (iii) The diversity of building block materials poses a challenge to developing a versatile and generic AM technology to fabricate multi-scale porous structures.

We propose the hypothesis that a multi-stage additive manufacturing process, including printable material preparation, 3D printing techniques, and post-processing, could offer a universal solution to build an agile AM process. This presentation analyzes how each stage can be better correlated to fabricate multi-scale porous structures. Additionally, we explored what could be done to optimize the resolution of the developed multi-stage process. Not only can the end-part shape fidelity be improved but also achieve a well-ordered pore arrangement. Furthermore, having built a versatile AM process, how to enhance the cost-effectiveness of manufacturing scalability was also included in the analysis. Experimental studies were first carried out to develop the generic multi-stage AM process for multi-scale porous structures. The primary stage used nano-scale porous material to prepare the feedstock printable ink. The ink design principle and the printability were analyzed with specific characterization techniques. In the second stage, a foamed ink was printed using direct ink writing process to fabricate 3D structures. Followed by the ambient pressure and room-temperature drying to create the macro-scale porous network. In the third stage, post-processing technologies were applied to the as-printed samples, producing the micro-scale porosity to conclude the three-stage AM process. Additionally, the physics-based, computational fluid dynamics (CFD) simulation studies were conducted to study the ink flow behavior and revealed the shear-thinning phenomenon during the direct ink writing process. These analytical studies were further extended to optimize the nozzle geometries to ensure smooth ink flow, process resolution, and end-part shape fidelity. With a high-fidelity three-dimensional (3D) printing process and the precise controllability of the porosity, we showed that the printed end-part exhibited a remarkably low thermal conductivity and durable mechanical strength. The major contribution of this work includes the development of the multi-stage, cost-effective AM process for multi-scale porous structures. Such integration of AM technology and porous structure offers unparalleled opportunities for concept-to-design-to-fabrication of multi-scale porous networks, enabling the multi-functionalities of the fabricated end-parts and broadening its applications.

Presenting Author: ZIPENG GUO University at Buffalo

Presenting Author Biography: Zipeng Guo is a Ph.D. candidate in the Industrial and Systems Engineering Department at the State University of New York at Buffalo, where he is advised by Dr. Chi Zhou. Zipeng’s current research focuses on developing a versatile multi-stage additive manufacturing process for multi-scale porous structure, process modeling and simulation, and functional material characterization. He has authored 12 journal papers, including the prestigious PNAS (Proceedings of the National Academy of Sciences), Nature Communications, and Advanced Functional Materials. His research outcomes have been recognized across several societies and found promising applications in thermal insulation, biomedical implantation, electronic devices, and energy conversion.

Authors:

ZIPENG GUO University at Buffalo
Chi Zhou University at Buffalo