With the increasing demand for ultra smooth planar components, the surface roughness should reach nanometer level, the surface shape accuracy should reach micron level, and there should be no surface and subsurface damage. The traditional ultra precision polishing techno-logy is low efficiency, high cost, difficult to control, easy to produce surface subsurface damage, which is difficult to meet the production requirements. Magnetorheological finishing (MRF) is a kind of ultra precision machining technology which uses the rheological property of MRF slurry in magnetic field. It is a new precision manufacturing method. The polishing process can be effectively controlled, and can achieve precision polishing, which can achieve ultra precision quality requirements. This paper analyzes and summarizes the key contents of magnetorheological fluid and magnetic pole in magnetorheological finishing. The components and common materials of MRF are described in detail, as well as three major indexes: settlement stability, magnetomechanical properties and shear yield stress. The results show that the sedimentation rate and stability of MRF are related to the composition of MRF. The sedimentation rate of MRF is different with different magnetic sensitive particles. Different additives can be used to change the sedimentation performance by changing the surface activity of magnetic sensitive particles. The only component of magnetorheological fluid is magnetic sensitive particle under the action of magnetic field, the magnetic sensitive particles gradually form a chain structure and are in the state of condensation. When the magnetization of the magnetic sensitive particles increases, the shear stress also changes, showing an obvious increase trend. At the same time, the influence of different configuration of magnetic pole on magnetic field and the influence of different arrangement of magnetic pole on magnetic field and polishing effect are summarized. The effects of different arrangement of magnetic poles on the size of magnetic field and the uniformity of polishing pad are described. Cylindrical and square cylindrical magnets are the most ideal permanent magnet shapes compared with other magnetic poles. In this paper, the new research directions of MRF technology are summarized, including cluster MRF technology, combined MRF technology which can process curved surface, global MRF polishing technology and ultrasonic MRF composite processing technology. The working principle and process effect of these methods are introduced. Finally, the current stage of MRF is analyzed, the problems existing in the research of polishing technology are summarized, and the future development direction is prospected. © 2022, Materials Review Magazine. All right reserved.
