Study On Controlled Magnetic Abrasive Finishing Machining

There are many long and thin smooth tubes used in medical treatment,biochemistry,spaceflight and food making. It is required that these tubes have a very fine surface roughness. But the traditional processes are restricted by tool's dimension, workpiece shape and material. It can not do the effective machining for these tubes and it needs a new process to solve these problems because of above factors.Magnetic abrasive finishing is a precise polishing method that the magnetic abrasive is the cutting tool. The abrasion pressure is controlled by a magnetic filed to produce a relative motion between the abrasives and the work surface. A limited amount of material will be removed to obtain the required surface. Owing to the magnetic field, the magnetic abrasives will become a flexible magnetic brush. When the cutting resistance is larger than magnetic force, the magnetic abrasives will roll and slide on the work surface. So this process can not do serious damage to the surface. Furthermore, the process doesn't need the strict precision of the equipment and the vibration nearly will not affect the surface quality. Because of these characteristic, magnetic abrasive finishing can do polishing for long tubes. In order to realize the mechanisms and practicability of magnetic abrasive finishing, the main work and achievements of this paper are listed as follow:(1) The finishing mechanisms of long tubes by magnetic abrasive finishing are investigated. Some investigations are done to analyze the forces exerted on magnetic abrasives and the movement of magnetic abrasive brush and the mechanism of the cutting.(2) Analyzed the magnetic field used in the magnetic abrasive finishing by finite element method and concluded the distribution of the magnetic field, which played a guide role in designing the magnetic abrasive finishing device. By the analysis we can know that the slotting magnetic poles play optimize effect in magnetic field distribution, improve the magnetic field intensity in the inner of the tube and finally promote machining efficiency.(3) In this paper, we design the experiments of controllable magnetic field magnetic abrasive finishing for inner surface. The abrasives are non-combined. The results demonstrate that the best surface roughness can be attained is 0.18μm.The research work above can overcome the deficiency of traditional processing methods. It has high processing efficiency and good effect on finishing quality and has guiding role on practical application.