Research On The Key Technology Of Combined Magnetorheological Fishing

With the rapid development of 3C electronic industry, aluminum alloy, sapphire, zirconia ceramics and other materials have been widely used in the field s of handheld devices, smart wearable devices, weapons and other equipments. As the huge quantity of user groups and appearance requirements for excellence, the demands of 3C products are increasing rapidly and suface quality requirements are getting higher and higher. Traditional double-sided polishing method can achieve precise surface for flat parts efficiently. But with the application of 2.5D and 3D surface in 3C products, the traditional polishing method is difficult to polish curved surfaces, and the precision of machine is very high. To solve these problems, the Magnetorheological Finishing(MRF) method is introduced to the 3C manufactuering, and the combined MRF technology is researched, which realize the acurate surface polishing of 3C products efficiently. This paper mainly focuses on the following aspects:The principles of combined MRF are described. The movements of flat surface polishing and curved surface polishing are analyzed, and the torques of each movements are calculated, which theoretically prove the feasibility of conbined MRF technology. Finally, the structure factors and control system of YHMRF-640 are presented, which provides the foundations for processing research.The electromagnet is designed based on the demends of polishing manner. The strength of magnetic field and the distribution of magnetic field lines are simulated by Ansoft Maxwell software. According to the analysis of simulation model, the magnet is manufactured, which proves the applicability of magnet. In order to improve the performance and lifespan of the magnet, the cooling methods are discussed, the temperature exaltation is calculated, the indirectly cooling method is defined,the transfomer oil is chose as the cooling medium. At last, the cooling circuit is designed base on the structure factors of electromagnet.The selection basis about each components of magnetorheological fluid are analyzed. The dispersion stability of magnetorheological fluid is researched. According to the theory, the magnetorheological fluid is formulated. The shear stress and viscosity of the magnetorheological fluid are tested, which shows that the magnetorheological fluid have excellent fludity in zreo manet and high shear stress in excitation. Finally, the failure modus of magnetorheological fluid are studied, and the corresponding measures of prevention are proposed.Applying the developed MRF machine and magnetorheological fluid, the influence regularity of parameters that magnetic field intensity, polishing gap, workpiece speed, rolling angle, magnetic particle size and magnetic particle mass percentage effect on material removal rate and surface gloss are studied by taking single factor experiments, which provides a good experimental basis for optimizing the process technology.