Study on magnetorheological nano-polishing using low-frequency alternating magnetic field

Abstract

With the development of electronics and optical industry, the high-efficiency ultra-precision polishing technologies of flat and curved surfaces are in high demand. The traditional magnetorheological polishing technology, using flexible polishing head, has the disadvantages of low polishing efficiency and small processing area. In this study, a novel tray-type magnetorheological polishing process using low-frequency alternating magnetic field excitation was developed to improve the efficiency of magnetorheological polishing for large surfaces and to make polishing magnetorheological cluster generate a cyclical fluctuation up and down, and then improve the cross-cutting effects of abrasives. With the developed excitation system, a large bowl-shaped varying magnetic field was generated in the working area, and the effects of current frequency, working gap, trough rotation speed, and workpiece rotation speed on the improvement rate of surface roughness and material removal rate were systematically investigated. A series of experiments were conducted on K9 glass specimens to verify the polishing performance. Experimental results show that the surface roughness of K9 glass was improved from 567.08 to 9.63 nm in 120 min.

Theoretical and Experimental Research on a Novel Method of Cluster Magnetorheological Finishing Based on Array Circular Holes Polishing Disk

“…Wu et al [6] proposed a new method of disk-MRF with a low frequency alternating magnetic field. Lopez et al [16] have studied that the yield shear stress of magnetic particles under the action of the magnetic field is related to its deflection angle θ.…”

“…The relationship between yield shear stress m  and shear strain  of carbonyl iron powder chain is described by Equation (6). In order to obtain the relationship between the shear strain  and the workpiece rotation speed, Hegger et al [17] established the relationship between the rotation speed of the rotator and the shear strain as follows:…”

Influence of Excitation Parameters on Finishing Characteristics in Magnetorheological Finishing for 6063 Aluminum Alloy

“…However, as magnetic grinding finishing involves point-contact polishing, the polishing area of the workpiece is very small, leading to low finishing efficiency. Yin and Wu proposed a disc-type magnetorheological finishing method using low-frequency alternating magnetic field excitation to enhance finishing efficiency [ 33 ].…”

Study on new magnetorheological chemical polishing process for GaN crystals: polishing solution composition, process parameters, and roughness prediction model

“…CMP can realize the smooth and flat processing of GaN crystals, but its efficiency needs to be improved further. Magnetorheological finishing is a non-damage processing technology [21][22][23][24][25], which can effectively realize sub-nanometer processing of hard and brittle crystal materials such as sapphire [26,27], silicon carbide [28,29], and optical glass [30][31][32]. However, research on GaN magnetorheological finishing has not been reported.…”