Additive manufacturing promises to revolutionize manufacturing industries. However, 3D printing of novel build materials is currently limited by constraints inherent to printer designs. In this work, a bench-top powder melt extrusion (PME) 3D printer head was designed and fabricated to print parts directly from powder-based materials rather than filament. The final design of the PME printer head evolved from the Rich Rap Universal Pellet Extruder (RRUPE) design and was realized through an iterative approach. The PME printer was made possible by modifications to the funnel shape, pressure applied to the extrudate by the auger, and hot end structure. Through comparison of parts printed with the PME printer with those from a commercially available fused filament fabrication (FFF) 3D printer using common thermoplastics poly(lactide) (PLA), high impact poly(styrene) (HIPS), and acrylonitrile butadiene styrene (ABS) powders (< 1 mm in diameter), evaluation of the printer performance was performed. For each build material, the PME printed objects show comparable viscoelastic properties by dynamic mechanical analysis (DMA) to those of the FFF objects. However, due to a significant difference in printer resolution between PME (X–Y resolution of 0.8 mm and a Z-layer height calibrated to 0.1 mm) and FFF (X–Y resolution of 0.4 mm and a Z-layer height of 0.18 mm), as well as, an inherently more inconsistent feed of build material for PME than FFF, the resulting print quality, determined by a dimensional analysis and surface roughness comparisons, of the PME printed objects was lower than that of the FFF printed parts based on the print layer uniformity and structure. Further, due to the poorer print resolution and inherent inconsistent build material feed of the PME, the bulk tensile strength and Young’s moduli of the objects printed by PME were lower and more inconsistent (49.2 ± 10.7 MPa and 1620 ± 375 MPa, respectively) than those of FFF printed objects (57.7 ± 2.31 MPa and 2160 ± 179 MPa, respectively). Nevertheless, PME print methods promise an opportunity to provide a platform on which it is possible to rapidly prototype a myriad of thermoplastic materials for 3D printing.
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Toward Geometric Control of Late-Stage Diffusion Properties for 3D Printed Biodegradable Microstructures
The ability to manufacture biodegradable structures at small scales is integral to a variety of applications in biological, medical, and pharmaceutical fields. Recent developments in additive manufacturing (or "three-dimensional (3D) printing") allow for biodegradable materials to be printed with high resolution; however, there is typically a limit with respect to a resolvable feature size (e.g., layer height) that dictates the minimum increments for tuning distinct degradation-mediated functionalities via print geometry. Here we investigate the potential to 3D print designs that afford additional degrees of control during intermediate stages between the complete biodegradation of microstructures that differ by a single layer height. Preliminary fabrication results revealed effective printing of tubular 3D biodegradable gelatin methacryloyl (GelMA) structures with outer diameters of 100 μm and wall thicknesses of 35 μm using two-photon direct laser writing (DLW)-based additive manufacturing. Simulation results for varying designs suggest that both the total degradation time as well as the diffusion dynamics through a microstructure during the final stage of biodegradation can be modulated via geometric means. Thus, the concepts presented in this work could open new avenues in areas including drug delivery and biomaterials.
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- Award ID(s):
- 1943356
- NSF-PAR ID:
- 10279895
- Date Published:
- Journal Name:
- 2021 IEEE 34th International Conference on Micro Electro Mechanical Systems (MEMS)
- Page Range / eLocation ID:
- 1036 to 1039
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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Such modeling and analysis help to elucidate the fundamental mechanisms that govern cathode performance and degradation in Li-S batteries. The current study also provides design strategies for the sulfur cathode as well as selection approaches to novel battery systems. References: Bhargav, A., (2020). Lithium-Sulfur Batteries: Attaining the Critical Metrics. Joule 4 , 285-291. Chung, S.-H., (2018). Progress on the Critical Parameters for Lithium–Sulfur Batteries to be Practically Viable. Advanced Functional Materials 28 , 1801188. Peng, H.-J.,(2017). Review on High-Loading and High-Energy Lithium–Sulfur Batteries. Advanced Energy Materials 7 , 1700260. Chu, T., (2021). 3D printing‐enabled advanced electrode architecture design. Carbon Energy 3 , 424-439. Shi, Z., (2021). Defect Engineering for Expediting Li–S Chemistry: Strategies, Mechanisms, and Perspectives. Advanced Energy Materials 11 . Figure 1more » « less
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- Free Publicly Accessible Full Text
-
Accepted Manuscript1.0
- Conference Paper:
- https://doi.org/10.1109/MEMS51782.2021.9375465
