Purpose Although material extrusion-based additive manufacturing (AM) techniques offer many advantages, their industrial application is limited by the relatively poor mechanical properties of the printed parts. Among the various methods for improving part’s structural integrity, in-process ultrasonic treatment is a promising approach for enhancing the mechanical and physical properties of the printed parts through different microscopic and macroscopic mechanisms. This technique effectively enhances part’s mechanical performance while maintaining the process versatility and eco-friendliness. Design/methodology/approach In this research, the impacts of both in-process ultrasonic parameters, such as sonication time and sonication power, and printing parameters, such as layer thickness, infill ratio and material, on the mechanical and physical properties of the printed parts are investigated. To elucidate the effect of each parameter on the outputs, response surface methodology (RSM) is used as design of experiments. Different mechanical and physical tests, including tensile strength measurements, surface roughness analysis, Shore D hardness evaluation, microscopy examinations, digital image correlation (DIC) and dimensional deviation measurements, were performed to quantify the impact of this in-process treatment. Findings The results demonstrate that in-process ultrasonic treatment significantly enhanced mechanical performance. Under optimal conditions (300 W power for 30 min), ultimate tensile strength (UTS) improved by up to 17.5% for PLA-CF and 21.8% for PETG-CF, with corresponding Young’s modulus increases of up to 13.2% and 16.4%, respectively. These gains were linked to microstructural and macroscopic enhancements; air gap analysis revealed a reduction in voids of up to 31.85%, and DIC analysis confirmed a more uniform strain distribution under load. This strengthening was accompanied by a tradeoff in ductility, wherein elongation at break decreased. While sonication slightly increased surface roughness and dimensional deviation, the effects on Shore D hardness were minor, confirming that the process improves structural integrity without significantly compromising geometric accuracy. Originality/value The novelty and value of this study lie in its systematic investigation of an in-process, bed-based ultrasonic treatment for fiber-reinforced composites. A clear link is established between process parameters (e.g. sonication power) and the resultant mechanical properties. The originality of this work stems from its elucidation of the underlying mechanisms: the process was demonstrated to effectively reduce internal porosity and enhance fiber-matrix bonding. Consequently, this research provides a practical, mechanism-driven methodology for enhancing the mechanical performance of additively manufactured components, thereby expanding their suitability for demanding industrial applications.
Barzegar et al. (Wed,) studied this question.