| Summary: | 碩士 === 國立臺灣大學 === 應用力學研究所 === 105 === Additive manufacturing (AM), also known as 3D printing, has been recognized as the next big thing of future technology in the recent years. Among all the related methods, fused deposition molding (FDM) is one of the most economical way, which extrudes the semi-molten material onto the substrate to construct artificial structures. Despite it has several benefits including of low cost, user-friendly, and rapid printing, it still suffers from a severe limitation on printing material, especially for the high viscous polymer (> 100,000 cP) such as polyetheretherketone (PEEK) with biocompatible, high mechanical strength, and chemical resistant properties. To this end, this study aims for developing the commercial 3D printer based on FDM for PEEK material.
In addition, commercial available FDM 3D printer mainly uses the mechanism of filament feeding, which has drawbacks of back-flow induced nozzle clogging and filament bulking phenomenon in high speed printing process, thus restricting its printing efficiency. Therefore, in this study, skipping the commonly used filament feeding in FDM for the first time, we’ve successfully developed pellet-based and screw-typed 3D printer for PEEK material in the injection molding concept with features of easy operation (saving one process on pellet to filament) and maintenance (no more nozzle clogging). Furthermore, the current apparatus supports the printing speed up to 370 mm/s with flow rate error controlled within 3% while conventional method is only 50 mm/s in 400 μm nozzle diameter. On the basis of this approach, we have successfully printed some specimens and the porosity induced by process imperfection can be greatly inhibited and the mechanical strength can be enhanced up to 96% in tensile strength compared to the bulk material in the first time. In addition, we also developed an exchangeable plane-typed printing head for large-area printing. Currently, the minimum dry film has achieved the maximum precision of 58 μm and the best surface roughness Ra has achieved in 1.56 nm.
To further demonstrates PEEK printer’s superiorities in the application of microfluidic device. This study also designed and printed the chemical resistant micro-reactor for the synthesis of liquid crystal and optically active molecules. The results show a higher yield (95%) and reaction velocity (180 times) than the conventional batch method (61%). Finally, we have also successfully printed high aspect ratio structure (hollowed Taipei 101) and intervertebral cage with interconnected channel.
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