Study On The Fluid Magnetic Abrasive Finishing Technology

The surface quality of work-piece has a great impact on the performance, life and reliability of work-piece. With the rapid developments of high speed and high precision equipments, the need for higher surface quality of work-piece is even more critical. The finishing techniques, which can be used to finish the intricate or complex part shape easily, efficiently and economically, are still challenges to the conventional finishing technology and are always concerned. Although some newly developed finishing techniques, such as chemical mechanical finishing, magnetic abrasive finishing and ultrasonic finishing etc., have been utilized successfully in some specific fields, the precision finishing of some intricate or complex part shape is still a big problem. In order to overcome the limitations of some conventional mechanical finishing techniques, the finishing technique of fluid magnetic abrasive (FMA) has been developed on the basis of our long term researches, and the finishing results have been proved in the experiments. FMA finishing technique is effective in the finishing of complex part shape, and is suitable for a variety of materials. Due to the finishing is done by loose abrasive particles in the FMA, the Ra roughness can be reduced to to a quite low surfaces roughness value (less than 0.01μm in some cases), and do not cause surface and subsurface defects. So, FMA can be used for the precision finishing of some complex surface. Furthermore, the finishing process is cost effective, adaptive and controllable. With all these advantages, FMA surface finishing technology has presented a great potential for innovation in finishing technology.In this dissertation, the mechanism of fluid magnetic abrasive (FMA) finishing, the finising techniques, finishing equipments, preparation techniques of FMA and a series of related key issues due to the application of the external magnetic field have been systematically investigated on the basis of microscopic and macroscopic scale. The method adopted throughout the present studies is a combination of theoretical analysis, experimental investigation and numerical calculation. The dissertation focuses on the mechanical mechanism of FMA under the applied magnetic field. The rheological property, the characteristic of magnetorheological effect as well as the influencing factors and the mechanical behavior are studies in detail and in depth.The main research is as follow:1. Based on the rheological analysis, the microscopic and macroscopic mechanical models are proposed.2. Based on the microscopic and macroscopic mechanical models, a process models is derived to elucidate the mechanism and material removal rate in FMA.3. The finishing mechanism of fluid magnetic abrasive, the finishing techniques of FMA and some key parameters in finishing process that may affect the finishing efficiency and the final surface roughness are studied in depth.4. The preparation technique of FMA, some key parameters of FMA and its testing techniques are proposed.5. An approach to FMA finishing equipments design is proposed.6. Numerical analysis and experimental investigations have been conducted to valided the proposed model. The experimental results show good agreement with the analytical predictions.In this dissertation, the finishing mechanism of fluid magnetic abrasive, the theoretic model, the preparation technique of FMA, some key process parameters are studied thoroughly and systematically. The finishing results of FMA are demonstrated and evaluated.