Effect of Infill Pattern and Printing Parameters on the Mechanical Properties and Surface Damage Behavior of <scp>FFF</scp> ‐Printed <scp>PLA</scp> Parts Under Erichsen Indentation

ABSTRACT This study investigates the influence of printing parameters—layer height, infill density, and infill pattern—on the mechanical performance and surface damage behavior of PLA components fabricated via Fused Filament Fabrication (FFF). The focus is on evaluating how these parameters affect force–displacement characteristics and crack initiation under Erichsen indentation testing. Fifteen parameter combinations were tested using three‐layer heights (0.10, 0.15, 0.20 mm), five infill densities (10%–90%), and seven infill patterns (Grid, Triangles, Cubic, Octet, Concentric, ZigZag, and Cross). Force–displacement curves, peak force, displacement, and energy absorption were analyzed. Post‐test surface damage was correlated with mechanical results to assess crack propagation and failure behavior. Results showed that increasing layer height raised maximum force but reduced ductility. Higher infill densities enhanced load‐bearing capacity but limited deformation, particularly above 70%. Triangles and Cubic patterns provided superior strength and controlled crack propagation, while Cross and Concentric patterns exhibited early failure. Surface damage analysis revealed that high infill density combined with optimal pattern design guided cracks more symmetrically. This work offers an experimental assessment of how FFF parameters affect both mechanical and failure behavior of PLA under indentation, contributing valuable insights for improving the structural performance of additively manufactured parts.