3D printing of highly reinforced composite

• Main Author: Teh, Jeslyn Jia Lin
• Other Authors: Hortense Le Ferrand
• Format: Final Year Project
• Language: English
• Published: Nanyang Technological University 2021
• Subjects: Engineering::Materials
• Online Access: https://hdl.handle.net/10356/147746
• Institution: Nanyang Technological University

It has always been a challenge to alter and influence ceramics and composites' microstructure that possess high solid concentration because of its high viscosity. With the advancement in material science and engineering, 3D printing of ceramic composite material has become the subject of very rapidly growing research activities. It opens a new horizon and unlimited possibilities for the manufacturing industry, especially in terms of geometrical flexibility, speed of manufacturing, and sustainability. One of the promising method is the development of suitable 3D ink slurry to fabricate ceramic into complex shapes while retaining its mechanical properties. In this study, we have used a complex bimodal system consisting of both nanoparticles and platelets of alumina in the form of slurry. To make the slurry printable, gelatin was used as a rheological modifier with different weight percentages with respect to total solid loading (wt %) and rhelogical properties were studied. The final ink was deemed desirable based on printability and shape retention. The rheology of ink is important in 3D printing process, as that determines the material ability to be extrudable and buildable. The rheology study covered flow behaviour of the ink under various shear rates, while frequency sweep test was conducted to study the viscoelasticity. Results obtained from rheology studies showed slurry containing gelatin are shear-thinning agents and their viscosities are dependent on wt % of gelatin added. The 0.5 wt. % and 0.6 wt.% gelatin concentration selected show higher storage modulus properties (G’>G”), better extrudability, and great shape retention. For 3D Bioprinting, 0.5 wt % gelatin concentration shows better resolution and shape fidelity than 0.5 wt % gelatin concentration. Based on experimental observations, it is concluded that ceramic composite ink with gelatin are deemed suitable for 3D printing. Due to project duration, not all gelatin samples could be studied in this project. Future studies on slurry could involve optimizing other printing parameters to explore its printing possibility.