Effect of liquid media, waiting time, and layer height on drop-weight impact performance of polylactic acid produced by additive manufacturing

Fusion deposition modeling (FDM) has developed remarkably over the last few decades as an innovative and versatile method of producing objects with complex design details. Polylactic acid (PLA), a bio-based polymer, is one of the most widely used thermoplastics in fabricating products with FDM due to its favorable mechanical properties, relatively low cost, and recyclability. However, most PLA studies in the literature have focused on evaluating its mechanical performance according to the 3D-printed parts to changing FDM parameters. This experimental study tries to elucidate high-speed mechanical performance of PLA samples at different waiting times depending on varying media such as dry, seawater, and distilled water. It aims to form a scientific bridge between the liquid absorption and high-speed deformation behavior of 3D-printed PLA. In addition, samples with three different layer heights were produced to investigate the combined effect of these media and process parameters on FDM parameters. Low-speed tensile tests, hardness tests, drop-weight impact tests, and damage inspections were carried out to analyze the samples thoroughly. These results indicated that there was an affirmative relation between the hardness values and layer height levels. The maximum drop weight force value was obtained in dry samples with 0.2 mm layer height. In addition, the maximum force was higher for samples stored in seawater than for other samples. The specific absorbed energy (SAE) value of the samples at 0.2 mm layer height after 15 days of waiting time was superior to that of the dry sample.