Polishing of SUS 304 Stainless Steel Using a New Magnetorheological Machining Technology Integrating Ultrasonic Vibration and Multi-point Electromagnet

The increasing demand for ultra-smooth surfaces and precise control over nanoscale microstructural features in modern manufacturing has driven the development of hybrid finishing technologies. In this study, a novel Ultrasonically Assisted Magnetic Abrasive Finishing (UAMAF) method is proposed, integrating conventional Magnetic Abrasive Finishing (MAF) with high-frequency ultrasonic vibration to enhance both material removal efficiency and surface quality. A key innovation of this study is the development of a Multi-Point Electromagnet system, composed of multiple independently energized poles arranged to generate localized, intensified magnetic fields. This configuration improves the control and distribution of magnetic abrasive particles during polishing. Numerical simulations of flat, grooved, and curved head geometries revealed that the curved design achieved the most uniform magnetic flux. Polishing experiments on SUS 304 stainless steel confirmed that optimized process parameters such as spindle speed and DC current enabled a surface roughness (Ra) reduction to 15 nm after 90 minutes. The synergistic effect between ultrasonic vibrations and the multi-point magnetic control significantly improved abrasive dispersion, reduced agglomeration, and intensified micro-cutting actions at the workpiece interface. This research highlights the effectiveness of the UAMAF technique enhanced by a multi-point electromagnet system, providing new insights into hybrid finishing mechanisms. The findings hold strong potential for industrial applications in fields demanding high-precision surface integrity, such as biomedical devices, aerospace components, and optical systems.