Optimization of FDM printing parameters for EVA and characterization of thermal, mechanical and forming properties of EVA/PLA blends

Purpose This study uses a granular feedstock printer to address the scarcity and molding challenges of high-elasticity materials for medical 3D printing. Polyethylene vinyl acetate (EVA), which is biocompatible, is blended with polylactic acid (PLA) to improve mechanical properties and moldability for medical product manufacturing. Design/methodology/approach Single-factor and orthogonal experiments were used to optimize the printing parameters for EVA. The performance of the EVA/PLA blends were comprehensively analyzed through thermal property characterization, melt flow rate testing, mechanical property testing and molding performance testing. Findings Optimal printing parameters were set at 210 °C nozzle temperature, 60 °C bed temperature, 30 mm/s printing speed and 0.4 mm layer thickness. Thermal analysis showed phase separation at 7.5% PLA content. Melt flow rate (MFR) testing revealed that adding 2.5% PLA increased MFR by 14.42%, with a 2.45% increase per additional 2.5% PLA. Mechanical tests indicated that a 10% PLA blend enhanced tensile yield strength by 256.59%, compressive strength by 102.32% and maximum force by 111.30%, though elongation at break decreased to 5.67% of pure EVA. Molding trials confirmed improved formability at 7.5% PLA content. Originality/value The optimal printing parameters for EVA granules and the ideal EVA/PLA blend ratio were determined. It was found that the mechanical and molding properties of the blend were improved compared to pure EVA. These findings provide valuable references for the application of FDM technology in the pharmaceutical manufacturing industry and offer guidance for material selection and experimental design in the future production of high-precision medical devices.