Speaker
Description
Additive Manufacturing (AM), also known as 3D printing, specifically Fused Deposition Modeling (FDM), is being widely applied in various fields such as aerospace, automotive, bioengineering, and architecture due to its advantages in constructing complex geometric structures, highly customized production, and minimizing material waste. However, FDM, which mostly utilizes thermoplastic resins as materials, exhibits mechanical characteristics that are not suitable for high-performance engineering composites. Moreover, the layer-by-layer deposition method used in FDM introduces issues such as interlayer gaps and residual stresses due to temperature gradients, which can lead to a degradation of the mechanical properties of the printed parts.
Therefore, carbon fibers are currently used as reinforcement materials to improve the mechanical properties of poor thermoplastics. However, carbon fiber production consumes a significant amount of energy and generates carbon dioxide emissions, leading to the high cost of carbon fiber and, subsequently, increased costs of FDM 3D-printed parts. To overcome this issue, researchers have investigated the application of recycled carbon fiber (rCF). Previous studies have shown that recycled carbon fiber exhibits approximately 70-90% of the strength compared to virgin carbon fiber (vCF) and that reinforcing thermoplastic parts with recycled carbon fiber through FDM can improve their strength. However, the fundamental issues of interlayer bonding and porosity in FDM have not been resolved. Additionally, increasing the fiber content to enhance the mechanical properties results in more porosity.
In this study, the researchers analyzed the effect of post-processing treatment, specifically annealing, as a solution to address the challenges of FDM. Annealing involves heating the material above its glass transition temperature and gradually cooling it while maintaining a closed chamber until the internal temperature reaches room temperature. The objective of this study was to analyze the effects of annealing temperature and time on the interlayer bonding and densification of FDM parts reinforced with recycled carbon fiber in order to improve their mechanical properties. Three different fiber content ratios were considered to evaluate the suitability of annealing based on varying levels of recycled carbon fiber content. Mechanical property improvement due to annealing was evaluated through tensile testing, and surface hardness analysis was conducted using Rockwell hardness testing. Morphological analysis using scanning electron microscopy (SEM) was also performed to visually assess the changes in interlayer gaps and internal porosity of FDM-printed parts under different annealing conditions.
This study provides insights into the effects of annealing on FDM parts reinforced with recycled carbon fiber and confirms the potential for expanding the application of thermoplastic FDM parts reinforced with recycled carbon fiber through enhanced mechanical properties.
References
CHICOS, Lucia-Antoneta, et al. Infill Density Influence on Mechanical and Thermal Properties of Short Carbon Fiber-Reinforced Polyamide Composites Manufactured by FFF Process. Materials, 2022, 15.10: 3706.
JAYANTH, N., et al. Effect of heat treatment on mechanical properties of 3D printed PLA. Journal of the Mechanical Behavior of Biomedical Materials, 2021, 123: 104764.
| Keywords | Recycled carbon fiber, Fused deposition modeling, Annealing, Interlayer bonding, Mechanical property |
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