Laser-assisted magnetorheological surface processing with magnetic arrays

To improve the surface quality and enlarge the effective polishing region of selective laser melting (SLM) fabricated 316L stainless steel, a laser-assisted magnetorheological polishing (LAMRP) method based on a cylindrical magnetic field array was proposed. Four N52 permanent magnet array configurations were designed and compared by Maxwell simulation. The results indicated that Array IV, featuring an N-S staggered arrangement, achieved the optimal performance with an effective polishing distance of approximately 4 mm. Based on this optimized array, LAMRP experiments were conducted to investigate the effects of laser power and polishing gap on surface roughness (Sa). Laser power showed a non-monotonic influence, with the minimum Sa of 138 nm obtained at 7 W. The lowest Sa of 189 nm was achieved at a polishing gap of 3.0 mm. The optimized magnetic array expands and uniformizes the polishing area, enabling stable nanometric finishing of SLM components.