This research work presents a comparative study of the tensile properties of polylactic acid (PLA) specimens per ASTM D638-14 fabricated by compression molding and 3D printing. PLA pellets from one batch are used in compression molding and filament extrusion for 3D printing. The compression molding process parameters are optimized to obtain an upper limit for mechanical properties of PLA specimens. Design of experiments (DoE) is used to evaluate the effect of processing temperature, pressure, and dwell time on the tensile properties of the specimens. The optimum compression molding trial resulted in slightly higher modulus for tensile specimens compared to 3D printing (3.33 GPa versus 3.22 GPa), while the average tensile strength was almost identical (59.9 MPa). Water absorption test is performed to evaluate moisture absorption of tensile specimens and compare their tensile properties in water saturated condition to the properties of dry specimens. 3D printed specimens showed a significant degradation of their tensile strength and modulus in water saturated condition by 28.4 % and 7.2 %, respectively. On the other hand, the tensile strength of the optimum compression molded specimens was decreased by only 12.0 %, while there was an increase of 14.1 % in tensile modulus.

这项研究工作针对通过压缩成型和3D打印制造的ASTM D638-14对聚乳酸（PLA）样品的拉伸性能进行了比较研究。一批的PLA颗粒用于3D打印的压缩成型和长丝挤出。优化压缩成型工艺参数以获得PLA样品机械性能的上限。实验设计（DoE）用于评估处理温度，压力和停留时间对样品拉伸性能的影响。与3D打印相比，最佳压缩成型试验使拉伸试样的模量略高（3.33 GPa对3.22 GPa），而平均拉伸强度几乎相同（59.9 MPa）。进行吸水率测试以评估拉伸试样的吸湿性，并将其在水饱和条件下的拉伸性能与干燥试样的性能进行比较。3D打印的样品在水饱和条件下的抗张强度和模量分别显着下降了28.4％和7.2％。另一方面，最佳压缩模塑样品的拉伸强度仅降低了12.0％，而拉伸模量却增加了14.1％。