This study presents the mechanical characterization of UV-curing acrylate systems. UV-curable polymers are commonly used in the stereolithography (SLA) technique to build multi-layered objects. Typically, the mechanical properties of the 3D-printed product are affected by the intrinsic material heterogeneity along the sample thickness. To understand what determines this heterogeneity, single layers of UV-curable polymer are characterized and the effect of process conditions on the mechanical properties is studied. Micro-compression experiments are carried out to determine the intrinsic mechanical properties which are representative of one single UV-cured layer. To determine the right conditions to generate maximally-cured micropillars, the evolution with irradiation time of monomer conversion, glass-transition temperature and yield stress has first been studied. Thereto, micrometer-sized pillars and dog-bone shaped samples have been prepared via UV-curing. Micro-compression measurements on maximally-cured micropillars are performed to study possible size effects. The results reveal that with decreasing pillar size, the yield stress decreases. Tensile measurements are performed on dog-bone shaped samples which have been processed in the same way as compared to the compression samples. These tensile tests show higher yield stress values when compared with compression tests. This size effect can be attributed to the rinsing with acetone during the sample preparation that leads to a removal of monomer from the crosslinked network. As a consequence, in the real 3D-printing process, the mechanical properties will depend on the feature size. In conclusion, a method is presented to determine the mechanical properties of one single layer of material used in the rapid-prototyping SLA process. The experimental procedure we adopted requires only a few millilitres of material and, therefore, is well suited for screening materials under real SLA process conditions.

这项研究提出了紫外线固化丙烯酸酯体系的机械特性。紫外光固化聚合物通常用于立体光刻（SLA）技术中以构建多层对象。通常，3D打印产品的机械性能会受到沿样品厚度的固有材料异质性的影响。为了理解是什么决定了这种不均匀性，对紫外线固化聚合物的单层进行了表征，并研究了工艺条件对机械性能的影响。进行微压缩实验以确定代表单个紫外线固化层的固有机械性能。为了确定产生最大固化微柱的正确条件，随着单体转化的照射时间而变化，首先研究了玻璃化转变温度和屈服应力。到此为止，已经通过紫外线固化制备了微米级的柱子和狗骨头形的样品。对最大固化的微柱进行微压缩测量以研究可能的尺寸影响。结果表明，随着柱尺寸的减小，屈服应力减小。对狗骨形样品进行拉伸测量，该狗骨形样品的处理方法与压缩样品相同。与压缩测试相比，这些拉伸测试显示出更高的屈服应力值。这种尺寸效应可归因于样品制备过程中用丙酮冲洗，这导致从交联网络中除去单体。结果，在实际的3D打印过程中，机械性能将取决于特征尺寸。总之，提出了一种确定在快速原型SLA工艺中使用的单层材料的机械性能的方法。我们采用的实验程序仅需要几毫升的材料，因此非常适合在实际SLA工艺条件下筛选材料。