Elucidation of polishing mechanism used in magnetic polishing brush

In recent times, there has been growing demand for environmentally friendly methods for finishing freeform surfaces (e.g., molding-die surfaces). This demand has generated interest in the development of a new polishing technology that uses less abrasive slurry and employs magnetic abrasive finishing. However, it is well known that the traditional magnetic polishing method is unstable and produces insufficient surface smoothness. In the present paper, we discuss the reasons causing instability in conventional magnetic polishing. We systematically investigate the magnetic pressure distribution characteristics and measure the pressure distribution of the magnetic brush during machining. Furthermore, we propose a new magnetic brush that uses steel balls (steel-ball brush) and abrasive slurry and compare this brush with a brush that uses iron powder paste (employed in the traditional magnetic polishing method). Finally, we present the processing mechanism of the proposed brush for polishing a flat surface on a three-axis machining center.