In recent years, the triply periodic minimal surface (TPMS) has emerged as a new method for producing open cell porous scaffolds because of the superior properties, such as the high surface-to-volume ratio, the zero curvature, etc. On the other hand, the additive manufacturing (AM) technique has made feasible the design and development of TPMS scaffolds with complex microstructures. However, neither the discrepancy between the theoretically designed and the additively manufactured TPMS scaffolds nor the underlying mechanisms is clear so far. The aims of the present study were to quantify the discrepancies between the theoretically designed and the AM produced TPMS scaffolds and to reveal the underlying mechanisms, e.g., the effect of building orientation on the discrepancy. 24 Gyroid scaffolds were produced along the height and width directions of the scaffold using the selective laser melting (SLM) technique (i.e., 12 scaffolds produced in each direction). The discrepancies in the geometric and mechanical properties of the TPMS scaffolds were quantified. Regarding the geometric properties, the discrepancies in the porosity, the dimension and the three-dimensional (3D) geometry of the scaffolds were quantified. Regarding the mechanical properties, the discrepancies in the effective compressive modulus and the mechanical environment (strain energy density) of the scaffolds were evaluated. It is revealed that the porosity in the AM produced scaffold is approximately 12% lower than the designed value. There are approximately 68.1 ± 8.6% added materials in the AM produced scaffolds and the added materials are mostly distributed in the places opposite to the building orientation. The building orientation has no effect on the discrepancy in the scaffold porosity and no effect on the distribution of the added materials (p > 0.05). Regarding the mechanical properties, the compressive moduli of the scaffolds are 24.4% (produced along the height direction) and 14.6% (produced along the width direction) lower than the designed value and are 49.1% and 43.6% lower than the μFE counterparts, indicating that the imperfect bonding and the partially melted powders have a large contribution to the discrepancy in the compressive modulus of the scaffolds. Compared to the values in the theoretically designed scaffold, the strain energy densities have shifted towards the higher values in the AM produced scaffolds. The findings in the present study provide important information for the design and additive manufacturing of TPMS scaffolds.

近年来，由于具有高的表面体积比，零曲率等优异的特性，三重周期性最小表面（TPMS）成为一种生产开孔多孔支架的新方法。一方面，增材制造（AM）技术使具有复杂微结构的TPMS支架的设计和开发变得可行。但是，到目前为止，理论上和设计制造上的TPMS支架之间的差异或根本机理尚不清楚。本研究的目的是量化理论设计和AM生产的TPMS支架之间的差异，并揭示潜在的机制，例如，建筑方向对差异的影响。使用选择性激光熔化（SLM）技术沿支架的高度和宽度方向生成了24个Gyroid支架（即，在每个方向上生成了12个支架）。量化了TPMS支架的几何和机械性能的差异。关于几何性质，对支架的孔隙率，尺寸和三维（3D）几何形状的差异进行了定量。关于机械性能，评估了支架的有效压缩模量和机械环境（应变能密度）的差异。结果表明，AM生产的支架的孔隙率比设计值低约12％。大约是68.1±8。AM生产的支架中添加了6％的添加材料，并且添加的材料大部分分布在与建筑物方向相反的位置。建筑物的方向不会影响脚手架孔隙率的差异，也不会影响添加材料的分布（p  > 0.05）。在机械性能方面，脚手架的压缩模量比设计值低24.4％（沿高度方向）和14.6％（沿宽度方向），分别比μFE支架低49.1％和43.6％。认为不完美的粘合和部分熔化的粉末对支架的压缩模量差异有很大的贡献。与理论设计的支架中的值相比，应变能密度已向AM生产的支架中的较高值转移。本研究的发现为TPMS支架的设计和增材制造提供了重要的信息。