Clarification Of Magnetic Abrasive Finishing Mechanism

Journal of Materials Processing Technology 143–144 (2003) 682–686 Clarification of magnetic abrasive finishing mechanism T. Mori∗ , K. Hirota, Y. Kawashima Department of Mechanical Engineering, Graduate School of Engineering, Nagoya University, Furo-cho, Chikusa-ku Room 253, Nagoya 464-8603, Japan Abstract In order to clarify the mechanism of magnetic abrasive polishing, a planar type process for a non-magnetic material, stainless steel, was examined. A magnetic abrasive brush was formed between a magnetic pole and a workpiece material, in which the summation of three kinds of energy necessary for magnetization of abrasives, i.e. repulsion between bundles (Faraday effect) and line tension of outer curved bundle was considered to be minimum. A normal force that pushes the abrasives on the brush end to be indented into the material surface is generated by the magnetic field. The magnetic abrasive brush will then be an extension of the magnetic pole. In this process, the tangential force acts to be the returning force created when the abrasive deviates from the magnetic balance point. Thus, the magnetic abrasives are expected to polish the material surface softly. © 2003 Elsevier Science B.V. All rights reserved. Keywords: Magnetic abrasive finishing; Polishing mechanism; Magnetic abrasive brush 1. Introduction A magnetic abrasive finishing process is defined as a process by which material is removed, in such a way that the surface finishing and deburring is performed with the presence of a magnetic field in the machining zone. The method was originally introduced in the Soviet Union [1], with further fundamental research in various countries including Japan [2]. Nowadays, the study of the magnetic field assisted finishing processes is being conducted at industrial levels around the world. Most of the previous research work has been focussed on the finishing characteristics and mechanism from a macroscopic point of view using the surface roughness profiles as the measure. However, those approaches do not adequately characterize the behavior of abrasive cutting edges acting against the surface during the removal process. This paper examines the magnetic field, acting forces and provides a fundamental understanding of the process mechanism. with one ␮m accuracy. N and S poles were separated 5 mm, and within the gap a workpiece vessel was placed. The vessel was supported by a thrust and radial bearing and rotated by a motor through a belt–pulley system. All components except the magnet were of non-magnetic material in order to suppress the influence of the magnetic field. Table 1 shows expe