Pneumatic dispensing of aqueous Al₂O₃ suspensions via material extrusion additive manufacturing
Material extrusion, also known as Robocasting or Direct Ink Writing (DIW) is an efficient and eco-friendly additive manufacturing method for fabricating large and thick ceramic components, such as alumina. While screw-based extrusion is the prevalent approach due to its precise control over printing...
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| Main Authors: | , , , , , |
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| Format: | Article |
| Language: | English |
| Published: |
Elsevier
2025-07-01
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| Series: | Next Materials |
| Subjects: | |
| Online Access: | http://www.sciencedirect.com/science/article/pii/S2949822825002680 |
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| Summary: | Material extrusion, also known as Robocasting or Direct Ink Writing (DIW) is an efficient and eco-friendly additive manufacturing method for fabricating large and thick ceramic components, such as alumina. While screw-based extrusion is the prevalent approach due to its precise control over printing parameters, pneumatic-based extrusion is gaining attention for its suitability in automated processes and reduced handling requirements. However, pneumatic extrusion faces challenges, primarily the narrower range of printable rheological behavior. Achieving a balance between extrudability and the self-supporting capacity of printed structures is critical. Moreover, bubble elimination, easily addressed in screw-based extrusion, remains a significant challenge in pneumatic systems. To overcome these issues, optimal concentrations of dispersants, ceramic loading, and additives were determined to achieve the desired shear-thinning rheological properties suitable for pneumatic extrusion. Additionally, this study, by employing a rapid one-step ball milling method for suspension preparation, is somewhat unique, providing a streamlined alternative to traditional processes. A degassing study was conducted to minimize bubble formation, ensuring print quality. Using the optimized parameters, including extrusion pressure and layer height, complex structures were successfully printed. After sintering at 1450 °C, the samples exhibited a 99.5 % dense microstructure with an average grain size of 1.71 µm. The alumina demonstrated excellent mechanical properties, achieving a hardness of 2094 HV at 1450°C, which is well aligned with the literature. |
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| ISSN: | 2949-8228 |