Modification of an acoustic panel through the alteration of 3D-printing infill patterns

Acoustic panels made of natural materials can be a viable option in resolving noise pollution on a commercial scale. With the advances of three-dimensional (3D) printing technology, acoustic panels can be printed and customised to the dimensions needed in the final application. The effects of 3D-printing infill patterns have on sound absorption performance have yet to be explored by researchers. Hence, this research aims to study and evaluate the sound absorption performance of an acoustic panel made from PLA-wood fibre composite through the alteration of 3D-printing infill patterns. Five physical samples of acoustic panels of different infill patterns, namely grid, rectilinear, triangular, honeycomb and cubical, were modelled with SolidWorks and fabricated through additive manufacturing (3D-printing) to observe their acoustic behaviour. The sound absorption coefficient (SAC) of each panel at a frequency range of 500 Hz to 3500 Hz was obtained through an Impedance Tube Test. The results obtained show that the Rectilinear infill pattern generated the highest SAC with a value of 0.554 among other infill patterns and has maintained an overall higher SAC throughout the increase in frequency, whereas cubic produces the lowest SAC overall. All five infill patterns shift a peak towards the region with higher frequency and narrows the bandwidth. The findings of this study provide a methodology in 3D-printing infill pattern alteration to enhance the sound absorption performance of acoustic panels made of natural materials.