The acoustic properties of FDM printed wood/PLA-based composites

The acoustic properties of the Fused Deposition Modelling (FDM) printed PLA wood composite was investigated. Initially tensile and flexural of wood PLA composite was studied with respect to varying layer thickness (0.15 mm, 0.20 mm, and 0.30 mm), infill density (30 %, 60%, and 90 %), and pattern (Layer, Triangle, and Hexagon). The outcomes demonstrated that the specimen produced with a hexagonal pattern, 90% infill density, and 0.2 mm layer thickness had the highest tensile (16 MPa) and flexural strength (16 MPa). Utilizing this optimized parameter, micro-perforated panels were printed and acoustic properties were studied. Five specimens with a 3 mm thickness, various perforation diameters (5 mm, 4 mm, and 3 mm), and architecturally tapered perforations were fabricated. Using the impedance tube approach, the sound transmission loss and sound absorption coefficients were measured. The findings indicate that, in comparison to all the printed specimens, tapered type perforation with an exterior diameter of 5 mm and an internal diameter of 4.7 mm showed highest sound absorption coefficient of 0.60 Hz. A viscous loss is obtained by its convergent hole diameter reduction, which results in sound attenuations and is easily absorbed in the micro-perforated panel. Similar to this, the specimen printed with smaller perforation diameters (3 mm) had a high sound transmission loss of 79 dB. The small diameter of the perforations prevented the passage of sound waves. The current study is anticipated to lay the groundwork for extensive future research on these classes of materials, potentially serving as a catalyst for advancements in FDM based polymeric materials research and development.