Sound Absorption Performance and Mechanical Properties of the 3D-Printed Bio-Degradable Panels

Abstract

The 3D printing process allows complex structures to be obtained with low environmental impact using biodegradable materials. This work aims to develop and acoustically characterize 3D-printed panels using three types of materials, each manufactured at five infill densities (20%, 40%, 60%, 80% and 100%) with three internal configurations based on circular, triangular, and corrugated profiles. The highest absorption coefficient values (α = 0.93) were obtained from the acoustic tests for the polylactic acid material with ground birch wood particles in the triangular configuration with an infill density of 40%. The triangular profile showed the best acoustic performance for the three types of materials analysed and, from the point of view of the mechanical tests, it was highlighted that the same triangular configuration presented the highest resistance both to compression (40 MPa) and to three-point bending (50 MPa). The 40% and 60% infill density gave the highest absorption coefficient values regardless of the material analyzed. The mechanical tests for compression and three-point bending showed higher strength values for samples manufactured from simple polylactic acid filament compared to samples manufactured from ground wood particles. The standard defects of 3D printing and the failure modes of the interior configurations of the 3D-printed samples could be observed from the microscopic analysis of the panels. Based on the acoustic results and the determined mechanical properties, one application area for these types of 3D-printed panels could be the automotive and aerospace industries.

Investigation into the Acoustic Properties of Polylactic Acid Sound-Absorbing Panels Manufactured by 3D Printing Technology: The Influence of Nozzle Diameters and Internal Configurations

“…In the case of these types of 3D-printed parts, it was also observed in other specialized studies [5,46,62] that the design of the core and the material itself have good sound-absorbing properties up to a frequency of approximately 2000 Hz, after which the absorption coefficient variation has a downward trend with low-intensity variations. The same type of variation in the absorption coefficient was also encountered in the case of all the analyzed samples made by the authors in this study, which were similarly obtained by 3D printing.…”

“…In this paper, the frequency dependencies of the sound absorption coefficient (α), the sound transmission loss (STL) and the reflection coefficient (β) of the 3D-printed samples using the transfer function method were investigated. The impedance tube presented two schematic configurations through which the acoustic performance of the 3D-printed sound-absorbing panels could be determined [46]. For the determination of the sound absorption coefficient, the equipment also included an anechoic termination component, and for the sound transmission loss, this anechoic termination part was removed (Figure 3b).…”

Manufacturing Process of Helicopter Tail Rotor Blades from Composite Materials Using 3D-Printed Moulds

“…This is possible because traditionally immediate-need TDVs are manufactured using computer numerical control (CNC) machines, which increase production and maintenance costs for this section that represents manufacturing preparation for a part/sub-part [25]. TDVs used in production that are currently suitable for additive manufacturing are represented by the following categories: templates for layout/marking [26,27], positioning/assembly devices [28,29], moulds for vacuum forming [30,31], moulds for injection moulding of plastics or vulcanisation of rubber [32][33][34], presses for bending thin sheets [35][36][37], and moulds for making composite parts [38][39][40].…”