An investigation into 3D printing of fibre reinforced thermoplastic composites
An investigation into 3D printing of fibre reinforced thermoplastic composites
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DOI：
10.1016/j.addma.2018.04.039
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发表时间：
2018-08-01
影响因子：
11
通讯作者：
Woods, B. K. S.
中科院分区：
文献类型：
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作者：
Blok, L. G.;Longana, M. L.;Woods, B. K. S.
熔丝制造（FFF）是一种3D打印技术，它允许通过喷嘴沉积热塑性材料逐层构建零件。该技术允许以传统制造方法无法实现的设计自由度制造复杂形状。然而，与普通工程材料相比，所使用的热塑性材料的机械性能较低。在这项工作中，研究了FFF的复合3D打印原料，其中将碳纤维嵌入热塑性基质中以增加强度和刚度。首先，回顾了FFF的关键加工参数，展示了纤维如何通过改变印刷材料的粘度和热分布来改变印刷动力学。最先进的复合3D打印提出，显示短纤维原料与连续纤维原料之间的区别。对这两种方法进行了实验研究。研究发现，使用MarkOne打印机打印连续碳纤维比未增强的热塑性塑料具有显著的性能提高，其机械性能与典型的单向环氧基复合材料相同。然而，该方法在设计自由度上受到限制，因为脆性连续碳纤维不能在小转向半径和锐角下自由沉积。嵌入短碳微纤维的长丝（类似于100 μ m）显示出更好的打印能力，适合与标准打印方法一起使用，但与纯热塑性塑料性能相比，机械性能仅略有提高。据推测，增加短纤维长丝的纤维长度有望提高机械性能，有可能接近连续纤维复合材料的力学性能，同时保持FFF工艺的高度设计自由度。
Fused filament fabrication (FFF) is a 3D printing technique which allows layer-by-layer build-up of a part by the deposition of thermoplastic material through a nozzle. The technique allows for complex shapes to be made with a degree of design freedom unachievable with traditional manufacturing methods. However, the mechanical properties of the thermoplastic materials used are low compared to common engineering materials. In this work, composite 3D printing feedstocks for FFF are investigated, wherein carbon fibres are embedded into a thermoplastic matrix to increase strength and stiffness. First, the key processing parameters for FFF are reviewed, showing how fibres alter the printing dynamics by changing the viscosity and the thermal profile of the printed material. The state-of-the-art in composite 3D printing is presented, showing a distinction between short fibre feedstocks versus continuous fibre feedstocks. An experimental study was performed to benchmark these two methods. It is found that printing of continuous carbon fibres using the MarkOne printer gives significant increases in performance over unreinforced thermoplastics, with mechanical properties in the same order of magnitude of typical unidirectional epoxy matrix composites. The method, however, is limited in design freedom as the brittle continuous carbon fibres cannot be deposited freely through small steering radii and sharp angles. Filaments with embedded short carbon microfibres (similar to 100 mu m) show better print capabilities and are suitable for use with standard printing methods, but only offer a slight increase in mechanical properties over the pure thermoplastic properties. It is hypothesized that increasing the fibre length in short fibre filament is expected to lead to increased mechanical properties, potentially approaching those of continuous fibre composites, whilst keeping the high degree of design freedom of the FFF process.