Chadha Charul, Olaivar Gabriel, Mahrous Mahmoud A, Patterson Albert E, Jasiuk Iwona
Department of Mechanical Science and Engineering, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA.
Department of Industrial and Enterprise Systems Engineering, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA.
Materials (Basel). 2024 Jun 1;17(11):2677. doi: 10.3390/ma17112677.
Additive manufacturing (AM) is often used to create designs inspired by topology optimization and biological structures, yielding unique cross-sectional geometries spanning across scales. However, manufacturing defects intrinsic to AM can affect material properties, limiting the applicability of a uniform material model across diverse cross-sections. To examine this phenomenon, this paper explores the influence of specimen size and layer height on the compressive modulus of polycarbonate (PC) and thermoplastic polyurethane (TPU) specimens fabricated using fused filament fabrication (FFF). Micro-computed tomography imaging and compression testing were conducted on the printed samples. The results indicate that while variations in the modulus were statistically significant due to both layer height and size of the specimen in TPU, variations in PC were only statistically significant due to layer height. The highest elastic modulus was observed at a 0.2 mm layer height for both materials across different sizes. These findings offer valuable insights into design components for FFF, emphasizing the importance of considering mechanical property variations due to feature size, especially in TPU. Furthermore, locations with a higher probability of failure are recommended to be printed closer to the print bed, especially for TPU, because of the lower void volume fraction observed near the heated print bed.
增材制造（AM）常用于创建受拓扑优化和生物结构启发的设计，从而产生跨越不同尺度的独特横截面几何形状。然而，增材制造固有的制造缺陷会影响材料性能，限制了统一材料模型在不同横截面中的适用性。为了研究这一现象，本文探讨了试样尺寸和层高对使用熔融长丝制造（FFF）工艺制造的聚碳酸酯（PC）和热塑性聚氨酯（TPU）试样压缩模量的影响。对打印样品进行了微观计算机断层扫描成像和压缩测试。结果表明，虽然TPU中由于层高和试样尺寸导致的模量变化在统计学上具有显著性，但PC中的变化仅因层高在统计学上具有显著性。对于不同尺寸的两种材料，在层高为0.2mm时观察到最高弹性模量。这些发现为FFF的设计部件提供了有价值的见解，强调了考虑特征尺寸引起的机械性能变化的重要性，特别是在TPU中。此外，建议将具有较高失效概率的位置打印得更靠近打印床，特别是对于TPU，因为在加热的打印床附近观察到较低的孔隙体积分数。
