Sebold Simon R, Neuwirth Tobias, Tengattini Alessandro, Cubitt Robert, Gilch Ines, Mühlbauer Sebastian, Schulz Michael
Heinz Maier-Leibnitz Zentrum (MLZ), Technical University of Munich (TUM), Lichtenbergstr. 1, 85748, Garching, Germany.
Univ. Grenoble Alpes, Grenoble INP, CNRS, 3SR, 38000, Grenoble, France.
Sci Rep. 2024 Aug 20;14(1):19348. doi: 10.1038/s41598-024-70030-4.
3D printing technologies such as fused filament fabrication (FFF) offer great opportunities to enable the fabrication of complex geometries without access to a workshop or knowledge of machining. By adding filler materials to the raw filaments used for FFF, the material properties of the plastic can be adapted. With the addition of neutron absorbing particles, filaments can be created that enable 3D printing of neutron shielding with arbitrary geometry. Two materials for FFF are presented with different mixing ratios of hexagonal Boron nitride (h-BN) and Polylactic acid (PLA). BNPLA25 with 25 %wt h-BN and BNPLA35 with 35 %wt h-BN are compared to the commercially available Addbor N25 material. To qualify the applicability of BNPLA25 and BNPLA35 as shielding material for neutron instrumentation, such as neutron imaging, we investigated the overall neutron attenuation, the influence of non-optimized print settings, as well as characterized the incoherent neutron scattering and the microstructure using neutron imaging, and time-of-flight small-angle-neutron-scattering. Finally, the tensile strength of the material was determined in standardized tensile tests. The measured neutron attenuation shows excellent agreement with analytical calculations, thus validating both the material composition and the calculation method. Approximately 6 mm (8 mm) BNPLA35 are needed for transmission of a cold (thermal) neutron beam. Lack of extrusion due to suboptimal print settings can be compensated by increased thickness, clearly visible defects can be mitigated by 11-18% increase in thickness. Incoherent scattering is shown to be strongly reduced compared to pure PLA. The tensile strength of the material is shown not to be impacted by the h-BN filler. The good agreement between the measured attenuation and calculation, combined with the adoption of safety factor enables the quick and easy development as well as the performance estimation of shielding components. BNPLA is uniquely suited for 3D printing neutron shielding because of the combination of non-abrasive h-BN particles in standard PLA, which results in a filament that can be printed with almost any off-the-shelf printer and virtually no prior experience in 3D printing. This mitigates the slightly lower attenuation observed as compared to filaments containing , which is highly abrasive and requires extensive additive manufacturing experience.
诸如熔丝制造（FFF）之类的3D打印技术为制造复杂几何形状提供了巨大机遇，无需进入车间或具备加工知识。通过向用于FFF的原始细丝中添加填充材料，可以调整塑料的材料性能。通过添加中子吸收颗粒，可以制造出能够3D打印任意几何形状中子屏蔽层的细丝。本文介绍了两种用于FFF的材料，它们具有不同比例的六方氮化硼（h-BN）和聚乳酸（PLA）混合比例。将含25%重量比h-BN的BNPLA25和含35%重量比h-BN的BNPLA35与市售的Addbor N25材料进行比较。为了验证BNPLA25和BNPLA35作为中子仪器（如中子成像）屏蔽材料的适用性，我们研究了整体中子衰减、非优化打印设置的影响，并使用中子成像和飞行时间小角中子散射对非相干中子散射和微观结构进行了表征。最后，通过标准化拉伸试验测定了材料的拉伸强度。测量得到的中子衰减与分析计算结果高度吻合，从而验证了材料成分和计算方法的正确性。对于冷（热）中子束的传输，大约需要6毫米（8毫米）的BNPLA35。由于打印设置欠佳导致的挤出不足可通过增加厚度来补偿，明显可见的缺陷可通过增加11 - 18%的厚度来减轻。与纯PLA相比，非相干散射明显减少。材料的拉伸强度不受h-BN填料的影响。测量衰减与计算结果之间的良好一致性，再加上安全系数的采用，使得屏蔽部件的快速简便开发以及性能评估成为可能。BNPLA特别适合用于3D打印中子屏蔽，因为标准PLA中含有无磨蚀性的h-BN颗粒，这使得细丝几乎可以用任何现成的打印机进行打印，而且几乎不需要3D打印的先验经验。这减轻了与含[具体物质未提及]细丝相比观察到的稍低衰减，[具体物质未提及]具有高磨蚀性且需要丰富的增材制造经验。
