Influence of the Fill Value Parameters on Acoustic and Physical–Mechanical Performance of 3D-Printed Panels

This study investigates the acoustic and mechanical performance of three types of 3D-printed polylactic acid (PLA) panels with varying infill densities (5-100%) and structural configurations. Using fused filament fabrication (FFF), panels were designed as follows: Type 1 (core infill only), Type 2 (core infill + 1.6 mm shell), and Type 3 (core infill + multi-layer shells). Acoustic testing via impedance tube revealed that Type 2 panels with a 65% infill density achieved the highest sound absorption coefficient (α = 0.99), while Type 1 panels exhibited superior sound transmission loss (TLn = 53.3 dB at 60% infill). Mechanical testing demonstrated that shell layers improved tensile and bending resistance by 25.7% and 36.9%, respectively, but reduced compressive strength by 23.6%. Microscopic analysis highlighted ductile failure in Type 2 and brittle fracture in Type 3. The optimal panel thickness for acoustic performance was identified as 4 mm, balancing material efficiency and sound absorption. These findings underscore the potential of tailored infill parameters in sustainable noise-control applications.