Enhanced Dimensional Accuracy of Material Extrusion 3D-Printed Plastics through Filament Architecture
Enhanced Dimensional Accuracy of Material Extrusion 3D-Printed Plastics through Filament Architecture
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DOI：
10.1021/acsapm.1c00110
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发表时间：
2021-04-06
影响因子：
5
通讯作者：
Vogt, Bryan D.
中科院分区：
文献类型：
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作者：
Ai, Jia-Ruey;Peng, Fang;Vogt, Bryan D.
用于通过熔丝制造的塑料的材料挤出的三维（3D）打印条件的优化通常涉及由于其正交要求而在机械性能和尺寸精度之间的权衡。增加的聚合物流动性通过链扩散改善了机械性能，以加强印刷道路之间的界面，但与高聚合物流动性相关的流动导致不准确性。在这里，我们描述了模型核壳几何形状在长丝中的应用，以解决这些权衡，并了解材料要求，以实现更高的尺寸精度。与商业聚碳酸酯基塑料和一个共同的高密度聚乙烯（HDPE）壳的核心系统的变化表明，这些长丝获得的拉伸性能是相对不敏感的印刷条件和选择的核心聚合物，但打印部分的尺寸精度显着提高的核心聚合物的玻璃化转变温度的增加。基于核-壳的部件的抗冲击性取决于核聚合物的选择，对于所检查的最低模量核，抗冲击性显著降低。虽然翘曲可以用核-壳长丝大部分减轻，但由于与HDPE结晶相关的大体积变化，印刷物体通常小于数字源。尺寸精度取决于包括长丝的聚合物的固化温度和机械性能、打印条件以及通过打印物体的3D扫描图像的逐层分析量化的物体的局部几何形状。通过这种分析，可以识别数字对象中的处理变化和一些结构，可以降低尺寸精度。核-壳长丝结构代表了一种模型几何形状，以了解聚合物共混物的打印潜力，其中共连续共混物中固化温度的分离可以提供一种提高性能的途径。
Optimization of three-dimensional (3D) print conditions for material extrusion of plastics by fused filament fabrication typically involves trade-offs between mechanical properties and dimensional accuracy due to their orthogonal requirements. Increased polymer mobility improves the mechanical properties by chain diffusion to strengthen the interfaces between printed roads, but flow associated with the high polymer mobility leads to inaccuracies. Here, we describe the application of a model core-shell geometry in filaments to address these trade-offs and understand the material requirements to achieve improved dimensional accuracy. Systematic variation of the core with commercial polycarbonate-based plastics and a common high-density polyethylene (HDPE) shell illustrates that tensile properties obtained with these filaments are relatively insensitive to printing conditions and selection of the core polymer, but the dimensional accuracy of the printed part improves markedly as the glass transition temperature of the core polymer increases. The impact resistance of the core-shell-based parts is dependent on the selection of the core polymer with a significant decrease in impact resistance for the lowest modulus core examined. Although warping can be mostly mitigated with the core-shell filaments, the printed object is generally smaller than the digital source due to large volume change associated with HDPE crystallization. The dimensional accuracy is dependent on the solidification temperature and mechanical properties of the polymers comprising the filament, print conditions, and the local geometry of the object as quantified by layer-by-layer analysis of 3D scanned images of the printed objects. Both processing changes and some structures in the digital object that can degrade the dimensional accuracy are identified through this analysis. The core-shell filament structure represents a model geometry to understand the potential for the printing of polymer blends where separation of solidification temperatures in cocontinuous blends could provide a route to improve performance.