Papers by Author: Yan Hua Zou

Abstract: In previous studies, it has been verified that the magnetic abrasive finishing process using alternating magnetic field can achieve higher finishing efficiency and surface quality, and nanolevel finishing of 5052 aluminum alloy material and SUS304 stainless steel material has been realized. In this study, the feasibility for ultra-precision finishing of polychlorotrifluoroethylene resin by this process was investigated, and the cutting mechanism of particles was discussed. As a result, the cutting depth of the particles is mainly affected by the size of the magnetic particles and abrasive particles. According to the experimental results, under optimized experimental conditions, the surface roughness of the workpiece can be improved from 112.83 nm Ra to 5 nm Ra within 15 minutes.

Abstract: Polychlorotrifluoroethylene material is used in industry as a material with excellent insulation, impact resistance and acid and alkali resistance. In this study, we used a magnetic abrasive finishing process with renewable abrasive particles to finish the surface of the polychlorotrifluoroethylene resin plate. Magnetic Abrasive Finishing (MAF) process is a technology that uses flexible magnetic brushes to improve the surface quality of materials. The performance of the magnetic brush is a key factor in surface finishing. In conventional MAF finishing, the number of abrasive particles in the magnetic brush is limited, and the position of the abrasive particles is relatively fixed, which will cause the cutting edge of the abrasive particles to gradually become dull and the finishing efficiency gradually decreases. This paper research the characteristics of the MAF process with renewable abrasive particles. This MAF process has a circulating system that uses a conveyor belt to renew abrasive particles. We use the polychlorotrifluoroethylene resin plate as the experimental processing object to conducted finishing experiment. And the surface roughness of the polychlorotrifluoroethylene resin plate is improved from 315 nm to 32 nm through this process.

Abstract: Magnetic abrasive finishing (MAF) is a precision surface polishing method. At present, most studies on planar MAF are focused on improving the surface roughness accuracy and the uniformity of roughness. In practical applications, the initial surface of the work piece is not only a rough surface, but also a flat surface without a uniform height. While the traditional processing method improves the surface roughness accuracy, the original surface is basically unchanged. In this paper, a processing method is studied. According to the uneven distribution of magnetic brushes, the reasonable distribution of processing speed and processing time can finally achieve the purpose of improving the surface flatness. At the same time, this paper analyzes the non-uniform characteristics of the magnetic pole and the magnetic brush itself, and verifies the effectiveness of the processing method through experiments.

Abstract: In this study, mainly researching the improvement of roundness of thick SUS304 stainless steel tube by interior magnetic abrasive finishing using a magnetic machining jig. The influence of reciprocating velocity of magnetic pole unit on the improvement of roundness of interior surface was studied by establishing the dynamic equation of magnetic machining jig. Experimental results showed that low reciprocating velocity of magnetic pole unit is conducive to the improvement of interior roundness of the thick SUS304 stainless steel tube. The reason is that the low reciprocating velocity of magnetic pole unit reduces the pitch of the helical motion and can produce greater finishing force of the magnetic machining jig.

Abstract: The traditional magnetic abrasive finishing (MAF) process, the magnetic flux density at the bottom of the magnetic pole is unevenly distributed, resulting in poor uniformity of the finished surface. Therefore, it is proposed to improve the surface quality by attaching a magnetic plate at the bottom of the workpiece to improve the magnetic field distribution. It is confirmed by simulation that the magnetic field distribution at the bottom of the magnetic pole is effectively improved after the magnetic plate is attached. It is proved through experiments that the magnetic plate-assisted MAF process can obtain a smoother surface. The experimental results show that the surface roughness of the glass lens improves from 246 nm Ra to 3 nm Ra through the magnetic plate-assisted MAF process within 45min.

Abstract: To further improve the finishing efficiency, it has been proposed to apply full-wave rectified current to the coil. In this paper, the effect of full-wave rectified current on the magnetic field and finishing force is studied. The effects of full-wave rectified current and alternating current on finishing characteristics were compared through experiments. The experimental results show that, with different magnetic particle sizes, the finishing efficiency shows different results. In the case of full-wave rectified current, when the average diameter of the magnetic particles is 30 μm, 75 μm and 149 μm, the finishing efficiency is higher than the alternating current, and when the average diameter of the magnetic particles is 330 μm, the finishing efficiency is lower than the alternating current.

Abstract: In this study, a new plane magnetic abrasive finishing method by using alternating magnetic field has been proposed to solve the problems such as the easy deformation and poorly restored of the magnetic brush in traditional magnetic abrasive finishing. Compared with the magnetic brush in traditional magnetic abrasive finishing, the magnetic brush can keep a relatively stable shape to finish the workpiece under the action of alternating magnetic field. In this paper, the variation of the finishing force in the alternating magnetic field is analyzed theoretically. In addition, in order to get the ultra-precision plane surface, the influence of the size of the magnetic particles, the size of the GC particles, and the frequency of the AC power on the finishing characteristics has been studied. The best experimental results show that the surface roughness of the workpiece is improved from 38 nm Ra to 6.33 nm Ra.

Abstract: Magnetic abrasive finishing technology has been known very well in finishing of stainless steel SUS304 pipes to mirror finish standard. However, the applications in softer metal such as aluminum A2017 were difficult due to soft metal characteristic itself. In 2002, Zou and Shinmura had developed a new method of magnetic field assisted machining process using magnetic machining jig for SUS304 pipe [. The development has since then expanded in many research. This research finds the optimum finishing condition for mirror finish standard in internal surface of aluminum A2017 pipe. We use a 100% polyester fabric that does not cause scratch on the material and found that the optimum pole-pipe gap to be 13mm to achieve the best surface roughness R_a of 0.020μm after finishing, from surface roughness R_a of 0.195μm before finishing.

Abstract: In this paper, a new plane magnetic abrasive finishing process by using alternating magnetic field is proposed to improve the efficiency and surface precision. In alternating magnetic field, the forced direction of magnetic particles is changing. Therefore, magnetic particles could produce the up and down movement, which promote the scatter of magnetic particles , improve the roll of abrasive particles and enhance the utilization of abrasive. In order to know well the magnetic intensity distribution in processing area, measured the magnetic flux density. Finishing force is important to understand the mechanism of material removal, investigated to the finishing force and contrasted to the movement changes of magnetic particles in water-soluble finishing fluid and oily finishing fluid. A set of experimental devices have been designed to realize surface polishing on C2801 brass plate, the results proved the feasibility of this method, which can improve the workpiece surface quality.

Abstract: To obtain an ultra-precision surface, this research developed a new type of magnetic finishing tool, “Ultra-precision Magnetic Abrasive Slurry”, for a magnetic field assisted internal finishing process. This ultra-precision magnetic abrasive slurry is made to mix simply the super-minute abrasive grains, super-minute globular iron particles, and oily grinding liquid. When the internal finishing was executed, the automatic mixing phenomenon of the Ultra-precision Magnetic Abrasive Slurry is caused, at the same time, super-minute abrasive grains and minute iron particles were uniformly distributed to the magnetic abrasive slurry. It was confirmed that a smooth mirror internal finishing for a SUS304 stainless steel tube is able to be achieved, by using the Ultra-precision Magnetic Abrasive Slurry that consists of the globular carbonyl iron particles (6μm in mean diameter) and diamond grains (0.25~0.75μm in mean diameter) and the oily grinding liquid. In this study, we examined the influence that the rotational speed of the magnetic pole exerted on the finishing characteristic. The results showed that the ultra-precision surface is successfully made, and the surface roughness has been improved from 320nm Ra to 3.37nm Ra .