Izod impact and hardness properties of 3D printed lightweight CF-reinforced PLA composites using design of experiment

3D printing plays an excellent role in the fabrication of customized parts for a variety of industrial sectors, but the printing parameters have a major influence on the performance of the printed parts. Therefore, this study aims to investigate a set of optimized parameters to manufacture cost-effective lightweight parts having enhanced impact strength and hardness properties. To accomplish this, carbon fiber (CF) reinforced polylactic acid (PLA) was used to fabricate Izod test specimens as per ASTM D256 standard with the help of a fused deposition modeling (FDM) 3D printer. An L9 array of Taguchi design of experiment was utilized for experimental runs and the performance of fabricated specimens was tested using an impact tester and digital Shore D durometer. It was observed that the Izod impact strength is highly influenced by the print speed and infill density. The maximum impact strength (113.84 J/m) was observed for the grid-type infill pattern at the highest nozzle temperature, median print speed, and median infill density. The maximum hardness observed as 79.6 (Shore D) is 37.95% higher than pure PLA due to the presence of fiber. The parameters for cost-effective lightweight parts with maximized impact strength and hardness properties were found at nozzle temperature 240 °C, print speed 120 mm/s, and infill density 50% with the grid type infill pattern. Differential scanning calorimeter (DSC) thermograms indicated thatthe crystallinity of CF-reinforced PLA is significantly altered during the 3D printing process due to the fast heating/cooling of the filament. The present study would provide a piece of extensive knowledge to designers and professionals working in this area for making proper judgments.