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Abstract：
Lattice structures have become an innovative solution for the improvement of part design, as they are able to substitute solid regions, maintain mechanical capabilities, and reduce material usage; however, dimensional quality control of these geometries is challenging. X-ray computed tomography (XCT) is the most suitable non-destructive metrological technique as it is capable of characterizing internal features and hidden elements. Uncertainty estimation of XCT is still in development, and studies typically use high-resolution calibrated devices such as focal variation microscopes (FVMs) as a reference, focusing on certain parts of the lattice but not the whole structure. In this paper, an estimation of the accuracy of XCT evaluation of a complete lattice structure in comparison to a higher-resolution reference device (FVM) is presented. Experimental measurements are taken on ad hoc designed test objects manufactured in polyamide 12 (PA12) using selective laser sintering (SLS), optimized for the evaluation on both instruments using different cubic-based lattice typologies. The results confirm higher precision on XCT evaluation in both qualitative and quantitative analysis. Even with a lower resolution, XCT is able to characterize details of the surface such as re-entrant features; as well, standard deviations and uncertainties in strut diameter evaluation remain more stable in all cells in XCT, identifying on the other hand reconstruction problems on FVM measurements. Moreover, it is shown that, using XCT, no additional evaluation errors were found in inner cells, suggesting that the measurement of external elements could be representative of the whole structure for metrological purposes.
摘要：
格结构已成为零件设计改进的创新解决方案，因为它们能够替代固体区域，保持机械能力，并减少材料的使用；然而，这些几何形状的尺寸质量控制是具有挑战性的。X射线计算机断层扫描（XCT）是最合适的非破坏性计量技术，因为它能够表征内部特征和隐藏元素。XCT的不确定性估计仍在发展中，和研究通常使用高分辨率校准设备，如焦点变化显微镜（FVM）作为参考，专注于晶格的某些部分，而不是整个结构。在本文中,与更高分辨率的参考器件（FVM）相比，提出了对完整晶格结构的XCT评估精度的估计。使用选择性激光烧结（SLS）对在聚酰胺12（PA12）中制造的特殊设计的测试对象进行实验测量，使用不同的基于立方的晶格类型对两种仪器的评估进行了优化。结果在定性和定量分析中都证实了XCT评估的较高精确度。即使分辨率较低，XCT能够表征表面的细节，如凹入特征；以及，在XCT的所有单元格中，支柱直径评估中的标准偏差和不确定性保持更稳定，另一方面，识别FVM测量的重建问题。此外，它表明，使用XCT，在内部单元格中没有发现其他评估错误，这表明外部元素的测量可以代表整个结构的计量目的。
