Digital light processing 3D printing of porous ceramics: A systematic analysis from a debinding perspective

Abstract

Using 3D printing technologies in manufacturing ceramic structures has received much attention. The requirements for advancing these technologies, especially vat photopolymerization, include segmented steps such as the optimization of ceramic suspension, the process parameters of 3D printing, and the thermal treatment conditions. Although 3D printing for dense ceramics has been studied extensively, more is needed to optimize 3D printing processes for fabricating porous ceramics. Mainly because the pore properties of porous ceramics determine their performance, an in-depth investigation is needed to determine how the thermal treatment conditions control these pore properties. To bridge this gap, in this study, ceramic (lead zirconate titanate) green bodies embedding pore-forming agents (polymethylmethacrylate) were fabricated by DLP (Digital Light Processing) 3D printing. They were debinded in a vacuum atmosphere at different heating rates (0.5, 1, and 2℃/min) for fabricating porous ceramics. These processes were followed by air debinding and sintering steps. Our findings revealed that the optimal heating rate condition produces the lowest shrinkages, surface roughness, and an improved stair effect. More importantly, this optimal condition led to porous ceramics without cracks and with pores that matched well with the size distribution of the pore-forming agent, which was used as a starting material. This systematic approach can be extended to combinations of various types of ceramics and pore-forming agents. Therefore, this study provides a guideline for determining the optimal heating rate condition to manufacture porous ceramics by DLP 3D printing technology.