eDIMES Lab - Laboratory of Bioengineering, Department of Medical and Surgical Sciences (DIMEC), Alma Mater Studiorum University of Bologna, 40138, Bologna, Italy.
Department of Civil, Chemical, Environmental and Materials Engineering (DICAM), University of Bologna, Via Terracini 28, 40131, Bologna, Italy.
J Mech Behav Biomed Mater. 2024 Aug;156:106598. doi: 10.1016/j.jmbbm.2024.106598. Epub 2024 May 24.
Material Jetting (MJ) 3D printing technology is promising for the fabrication of highly realistic surgical simulators, however, the changes in the mechanical properties of MJ materials after post-printing treatments and over time remain quite unknown. In this study, we investigate the effect of different post-printing processes and aging on the mechanical properties of a white opaque and rigid MJ photopolymer, a white flexible MJ photopolymer and on a combination of them. Tensile and Shore hardness tests were conducted on homogeneous 3D-printed specimens: two different post-printing procedures for support removal (dry and water) and further surface treatment (with glycerol solution) were compared. The specimens were tested within 48 h from printing and after aging (30-180 days) in a controlled environment. All groups of specimens treated with different post-printing processes (dry, water, glycerol) exhibited a statistically significant difference in mechanical properties (i.e. elongation at break, elastic modulus, ultimate tensile strength). Particularly, the treatment with glycerol makes the flexible photopolymer more rigid, but then with aging the initial elongation of the material tends to be restored. For the rigid photopolymer, an increase in deformability was observed as a major effect of aging. The hardness tests on the printed specimens highlighted a significant overestimation of the Shore values declared by the manufacturer. The study findings are useful for guiding the material selection and post-printing processing techniques to manufacture realistic and durable models for surgical training.
材料喷射（MJ）3D 打印技术在制造高度逼真的手术模拟器方面具有广阔的前景，然而，打印后处理和随时间推移对 MJ 材料机械性能的影响仍知之甚少。在本研究中，我们研究了不同打印后处理和老化过程对一种白色不透明刚性 MJ 光聚合物、一种白色柔性 MJ 光聚合物以及它们的组合的机械性能的影响。对均质 3D 打印试样进行了拉伸和邵氏硬度测试：比较了两种不同的支撑去除（干燥和水）后处理和进一步表面处理（甘油溶液）的方法。在打印后 48 小时内以及在受控环境中老化（30-180 天）后对试样进行测试。所有经不同打印后处理（干燥、水、甘油）处理的试样组在机械性能（即断裂伸长率、弹性模量、拉伸强度）方面均表现出统计学上的显著差异。特别是，甘油处理使柔性光聚合物更刚性，但随着老化，材料的初始伸长率趋于恢复。对于刚性光聚合物，老化是导致其变形能力显著提高的主要因素。对打印试样进行的硬度测试突出表明，制造商声明的邵氏值存在显著高估。研究结果有助于指导材料选择和打印后处理技术，以制造用于手术培训的逼真且耐用的模型。
