| As an important surface finishing technology, magnetic abrasive finishing has a better grinding ability, self-sharpening, adaptability and it has litter cutting heat and no deteriorated layer etc. It has a wide range of uses for some complex parts. In the magnetic abrasive machining, one of the main factors that affect the processing is the magnetic force. And the size of the magnetic force is closely linked to the magnetic field device. At the current, electromagnet and permanent magnet can be used as the magnetic source. The advantage of electromagnet is that to achieve continuously adjustable magnetic field easily by the regulated current. However, its volume can be relatively large and easy to heat. Also, it is difficult to achieve rotating. With the development of the new generation Nd Fe B permanent magnet materials, permanent magnets can have both small volume and strong magnetic field. The device with permanent magnets has simple structure and can be easy to achieve rotation. To this end, the permanent magnets as magnetic source are proposed. Then research and experimental studies of the magnetic field generating means are carried out. The main contents are as follows:1. The developments at home and abroad of magnetic abRasive finishing have been done a brief overview. Then the research is presented in this paper: development of adjustable magnetic field device about rotating surface in magnetic abrasive finishing and experimental verification.2. Stress analysis of bore in magnetic abrasive machining is made, and then the main factors affecting the magnetic abrasive machining is put forward. Using a permanent magnet as magnetic source of the magnetic field generated device, the adjustable magnetic field device have been designed. The size of the permanent magnet and a protective cover is determined.3. Geometry simulation model of the adjustable magnetic field generator is built. Viscoelastic magnetic abrasive particles are simplified into iron ball. Then in Maxwell software, the simulation of the particles' magnetic flux density and force are conducted under the condition of the different number and angles etc. of magnetic poles. When double 60°magnetic poles are arranged at N-S 90 °, abrasive force is the biggest, so is the Magnetic flux density of particles.4. Using the HAD-F-30 multi-dimensional high-precision digital magnetic measurement system, tests are conducted for magnetic field under the arrangement of different magnetic poles and numbers etc. The test results are consistent with the simulation.5. A viscoelastic magnetic abrasive tool is prepared. The experimental study of the aluminum alloy inner surface was conducted at the condition of poles of different angular size, the different number of poles and different magnetic poles angles arrangement using designed magnetic field generating device and prepared abrasives. By experiment, Effect of 60°poles arranged N-S 90 ° is better than other angles arranged. The surface roughness Ra of the aluminum tube and Rz values were reduced from 0.911?m 5.111?m 0.126?m and 1.065?m and decreased the percentage of 86.16% and 79.16%. At four 60°poles N-N-S-S arrangement, the surface roughness Ra of the aluminum tube and Rz values are reduced from 1.187?m 6.313?m and 0.441?m and 0.035?m, the percentage decline of 97% and 93%. Processing effect is obvious. |
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