Experimental and Statistical Evaluation of Infill Density Effects on the Mechanical Properties of FDM-Printed PLA, ABS, PC, and PETG Engineering Materials

Additive manufacturing (AM) has become prominent among advanced manufacturing technologies in recent years due to the advantages it offers in design flexibility, low material waste, and digitalization of the manufacturing process in cases where complex geometries are difficult or costly to produce with traditional methods. Fused deposition modeling (FDM) technology, which is based on the modeling of thermoplastic polymers by melting them layer by layer in a controlled manner, has become widespread in both industrial and academic applications due to its simplicity of process, low equipment cost, wide material compatibility, and sustainable manufacturing approach, and is effectively used in many areas from rapid prototyping to functional final products. In this study, the mechanical performances of different engineering polymers (ABS, PC, PLA, and PETG) produced with the FDM method at 30% and 60% infill densities were evaluated comparatively. The produced specimens were subjected to tensile, Charpy impact, hardness, and SEM analyses; structural strength and microstructure properties of the materials were examined. The results revealed that each material exhibited unique mechanical properties suitable for different applications. ABS was found suitable for applications requiring energy absorption with its superior impact absorption capacity and ductility. PC attracted attention with its highest strength and rigidity values, indicating that it can be preferred in structural parts where mechanical strength is critical. While PLA, one of the sustainable materials, stands out for biomedical components with its high ductility and flexibility properties, PETG provides advantages for carrier structures thanks to its better impact resistance and dimensional stability. The findings reveal that FDM technology can optimize mechanical properties through parameters such as material type and infill density, thereby providing a useful basis for material selection and design optimization in engineering applications.