Optimizing impact resistance of FFF-printed PLA parts: a comprehensive analysis of infill patterns and process parameters

Purpose This study aims to systematically investigate how various infill patterns and process parameters influence the impact behavior of 3D-printed polylactic acid (PLA) parts produced via fused filament fabrication (FFF). Design/methodology/approach The research used instrumented Charpy impact testing based on ISO 179-2 standard to evaluate the impact behavior of PLA specimens. An initial screening experiment evaluated ten commonly used infill patterns to identify candidates. Subsequently, four promising patterns were selected for optimization through a Taguchi designed experiment, considering key process parameters such as layer height, printing speed, nozzle temperature and nozzle diameter. Statistical analysis was used to determine influential parameters on mechanical performance. Findings Among the tested designs, the octet achieved the highest peak force of 521.20 N, outperforming the zigzag and gyroid, which indicates its superior resistance to impact loads. The cubic subdivision pattern exhibited consistent but moderate strength, making it suitable for applications requiring reliability. The zigzag exhibited the highest total energy absorption of 0.750 J, demonstrating its superior capability to dissipate impact energy. ANOVA results revealed that the infill pattern was responsible for 70.68% of the total variation in impact performance, while nozzle diameter contributed 13.94%, highlighting the dominant role of internal structure design in determining mechanical properties. Optimal mechanical performance was observed at a printing speed of 40 mm/s and a layer height of 0.14 mm, which correlated with higher peak force and improved energy absorption. Originality/value The findings offer actionable guidelines for designing lightweight, durable and cost-efficient components, bridging the gap between academic research and industrial application.