| Metal material magnetorheological finishing (MR finishing) technology uses the rheological property of magnetorheological fluid (MR fluid) under magnetic field, so that the grinding force between abrasive and workpiece is generated to achieve the finishing effect. Compared with traditional finishing method, metal material MR finishing technology has good flexibility and controllability, and it can realize the finishing of complex surface which is made of metal material without affecting physical and mechanical properties of its surface.This paper studies the composition, properties and preparation technology of MR polishing fluid, and prepares the MR polishing fluid that meets the requirements of metal material MR finishing well; On the basis of studying the rheological mechanism of MR polishing fluid, the micro-structure of abrasive grinding workpiece and metal material MR finishing mechanism have been analyzed, the shearing stress of MR polishing fluid in the machining area is analyzed and calculated, also the material removal rate model is constructed; The magnetic field generating module used in experimental apparatus is studied, and the original arrangement of magnetic pole is improved by using the design theory of magnetic circuit and processing principle of MR finishing, the strength and distribution of the magnetic field in the machining area are simulated by using ANSYS, results show that the improvement is effective. Selecting the experiment parameters, then the experiments are designed by using the orthogonal experimental method, the MR finishing technology is studied, and the influence rules of main process parameters are analyzed, the optimum process parameters for a particular material are found out. Through the theoretical and experimental study mentioned above, this experiments have obtained the best technology parameter for duralumin 2A12 and quenched 40Cr in metal material MR finishing, using this technology parameters to processes the duralumin 2A12 and quenched 40Cr, the minimum surface roughness value can be reached Ra0.275 and Ra0.14 respective. |
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