Enhancing PLA Strength and Layer Adhesion: Physical and Microstructural Insights from Vibration-Assisted FFF/FDM

Material Extrusion (MEX), particularly Fused Filament Fabrication (FFF), commercially known as Fused Deposition Modeling (FDM), has become one of the most widely used additive manufacturing technologies for producing polymer components. However, the mechanical performance of printed parts remains limited by weak interlayer bonding and internal porosity. This study investigates the effectiveness of controlled low-frequency bed vibration in improving the physical and mechanical properties of PLA components manufactured by vibration-assisted FFF/FDM. The influence of printing speed, raster angle, and vibration level was experimentally evaluated through tensile, flexural, surface roughness, Fourier Transform Infrared Spectroscopy (FTIR), and Scanning Electron Microscopy (SEM) analyses. Response Surface Methodology (RSM) was employed to optimize the process parameters with respect to tensile strength, yield strength, flexural strength, and surface quality. The results demonstrate that moderate bed vibration (Level 2) provides the best overall performance, improving the mechanical properties by approximately 8-15% compared with conventional printing. SEM observations revealed an approximately 60% reduction in average pore size, together with enhanced filament fusion and interlayer adhesion, while FTIR analysis confirmed that the chemical structure of PLA remained unchanged. These findings demonstrate that controlled mechanical bed vibration is a simple and effective strategy for enhancing the quality, reliability, and structural performance of FFF/FDM-printed PLA components. The proposed approach also provides practical guidelines for optimizing additive manufacturing processes and supports the development of advanced polymer manufacturing capabilities in Hail's growing industrial sector.