A comparative experimental work on the drop-weight impact responses of thermoplastic polymers produced by additive manufacturing: combined influence of infill rate, test temperature, and filament material

Abstract

In recent years, the topic of additive manufacturing of polymer materials has gained high acceleration in terms of scientific aspects due to the perfect prototyping capacity, clean production ability, and fast manufacturing opportunity of layer-by-layer fabrication technology. However, the majority of the studies have been directed to the exploration of the mechanical performance of three-dimensional (3D)-printed materials according to changing production variables. Different from the previous efforts, this experimental work is the first initiative to comprehend the low and high-speed mechanical performance of two different thermoplastic materials depending on the shifting test temperatures in a comparative manner. For polylactic acid (PLA) and polyamide 6 (PA6), the combined effect of the infill rate and high-speed drop weight deformation was analyzed for the first time in the technical literature. For this purpose, low-speed tensile tests, differential scanning calorimetry (DSC) and dynamic mechanical analysis (DMA) analyses, drop-weight impact tests, and damage inspections were made elaboratively. The results showed that PLA samples had superior mechanical responses at 25 degrees C, but the case was the opposite and in favor of PA6 above the glass transition. Specific absorbed energy values increased with decreasing infill rates both for PLA and PA6. Furthermore, PA6 samples remained united after the drop-weight deformation at higher temperatures, while PLA lost its integrity.