Designing a High-Performance Glass Bead/glass Fibre/polyamide 12 Hybrid Composite for Commercial Multi Jet Fusion Production

Multi Jet Fusion (MJF) is a powder bed fusion additive manufacturing technique increasingly adopted in commercial production due to its efficient material utilisation and high throughput. However, MJF-printed objects still suffer from anisotropic reinforcement or low stiffness, and hybrid powders designed to enhance the mechanical performance of parts remain commercially unavailable. In this work, a novel glass bead/glass fibre/polyamide 12 (GB/GF/PA12) hybrid composite was designed to improve powder printability and provide significant isotropic reinforcement. The incorporation of particulate GB improved the powder flowability and decreased part porosity, thus contributing to increased ultimate tensile strength of 55.04, 69.43, and 42.67 MPa in the X, Y, and Z orientations. The designed GB/GF/PA12 composite demonstrated an over 400% increase in the tensile modulus in the Y orientation, reaching up to 7.20 GPa and significantly outperforming PA12-based specimens fabricated via selective laser sintering and MJF. This composite also demonstrated good compatibility with the commercial MJF printer, yielding specimens with good dimensional stability and comparable tensile properties to the specimens printed on MJF testbed. This work not only provides a commercially viable hybrid-reinforced powder but also serves as a guideline for developing future high-performance polymer composites tailored for advanced additive manufacturing applications.