Surface uniformity enhancement in artificial joint polishing via halbach array-assisted magnetic liquid metal abrasive flow

To overcome surface non-uniformity issues in abrasive flow polishing of complex-curvature artificial joints, a Halbach array-assisted magnetic liquid metal abrasive flow polishing method is proposed. Magnetic nanoparticles are introduced into a liquid metal carrier to form a magnetically responsive medium, which enables precise control over abrasive particle migration in weak-flow regions through the single-sided enhanced magnetic field generated by the Halbach array. Numerical simulations indicate that at a flow velocity of 3 m/s, the average velocity in weak-flow regions increases from 1.29 to 1.51 m/s, while the average surface pressure rises from 9288 Pa to 14,308 Pa. Turbulent kinetic energy and pressure–velocity (PV) values increase by 150% and 83.3%, respectively. Erosion analysis demonstrates a 145% improvement in material removal efficiency in weak-flow regions, effectively reducing polishing blind regions by enhancing particle dynamics and energy transfer. Experimental validation corroborates these numerical findings. Surface roughness in weak-flow regions decreases from 121 nm to 72 nm, corresponding to a 40.5% reduction. The maximum surface roughness variation between different regions decreases from 52.2 nm to 13.6 nm, indicating a 73.9% improvement in polishing uniformity. These results highlight the significant advantages of this method in enhancing both polishing efficiency and uniformity for complex biomedical surfaces.