| This project is supported by Shanxi Provincial Youth Science Foundation "The new finishing technology of viscoelasticity magnetic abrasiv rotating magnetic field inside surface of hole"(2011021021-4).As a new type of precision surface finishing tool, viscoelasticity magnetic abrasive which is viscoelastic and liquidity under the effect of magnetic field force can adapt to complex structured surfaces very well and form a conformable "flexible finishing film" on the machined workpiece surface. Then, micro/nano level finishing is achieved by a relatively rapid motion with workpiece surface.The properties of the viscoelastic magnetic abrasives are the main factors affecting the surface finishing effect. On the basis of current research on the preparation of viscoelastic magnetic abrasive, from the interface between filled particles and the matrix of viscoelastic magnetic abrasive, this paper studies the main failure reason of the viscoelastic magnetic abrasive and the influence of interfacial properties on the viscoelastic magnetic abrasive finishing effect. The methods to improve the interface bonding strength were proposed, One of them is the surface modification by coupling agent for filler particles. It is proved by theoretical analysis, numerical simulation and experimental study that this method can improve the finishing effect of viscoelastic magnetic abrasives.Main researeh contents are as follows:1. The material types of the viscoelastic magnetic abrasive is determined. The interface mechanism between particles and matrix of viscoelastic magnetic abrasive is analyzed, as well as the failure reason of viscoelastic magnetic abrasive. Furthermore, according to the theory of particle filled composite material, the interface debonding mathematical model of viscoelastic magnetic abrasive is established, The factors affecting interface debonding is determined. Finally, viscoelastic magnetic abrasive’s finishing mechanism is stated based on analysis of dynamic and static mechanics of viscoelastic magnetic abrasive.2. Theoretical studies are carried on using ANSYS analysis software, including of establishing a microstructure model of viscoelastic magnetic abrasive, calculating the filling particles (Fe powder and SiC particles) influence on the viscoelastic magnetic abrasive internal stress distribution, analyzing the failure mechanism of viscoelastic magnetic abrasive, calculating and discussing the influence of filling particle volume fraction, particle size and shape on the interface debonding.3. Filler particles surface modification method and process is studied. The surface modification of SiC particles and Fe powder were made by using coupling agent. The influence of coupling agent on the dispersion and compatibility of SiC particles and Fe powder in the matrix is analyzed, as well as the improvement of interface bonding. The preparation process of viscoelastic magnetic abrasive is established, including the matrix preparation, and the matrix and abrasive mixed process of viscoelastic magnetic abrasive, etc.4. By means of H62brass tube inner surface finishing machining experiment, the effect of filler particle size, filler volume fraction, and kind and amount of coupling agent on the finishing properties of viscoelastic magnetic abrasive were studied, Thus a set of optimum process parameters is determined. |
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