In recent years, in addition to high-speed and high-precision machining, it has become important that the machined surface has high quality. However, the evaluation method of surface quality is not fixed, and it is usually evaluated by comparative photographs or appearance of the machined surface. In this research, we propose a method to evaluate surface quality by correlating the index of luminance measured by a luminance meter and the index of surface roughness measured by a laser microscope to the machined surface. The surface quality was evaluated for the machined surfaces with different conditions such as pick feed.

Machining conditions in float polishing method have been determined empirically and there is a need to elucidate the levitation principle of the workpiece and to propose a theoretical method to determine the machining conditions. In this research, the levitation quantity of the workpiece was measured by the displacement sensor and found to be about 4 µm. The order of this value agreed with the prediction in the literature. From the FEM simulation of the thin film fluid based on the Reynolds equation, it was predicted that the pressure distribution under the workpiece was non-uniform and cavitation was generated.

The scheduling of feed-rate is an important procedure in CNC finishing of high-precision optical surfaces. Since the polishing process is described as the convolution operation between a tool influence function and a dwell-time map, deconvolution operation gives an optimal dwell-time map. However, physical achievability of the obtained dwell-time map is not considered. This research elucidates the effect of the bulk removal, a constant removal layer across the surface, on the convolution process in spatial domain and time domain. Based on this investigation, we propose a theory that has the potential to analytically adjust dwell-time, feed-rate, and acceleration without compromising the surface accuracy, and to predict the total machining time as a function of the bulk removal.

The magnetic abrasive finishing (MAF) process is one of the ultra-precise surface finishing processes, but the traditional MAF process will reduce the finishing efficiency due to abrasive wear during processing. Therefore, in order to improve the finishing efficiency and surface quality, we proposed the MAF process using an alternating magnetic field. The effectiveness of this method has been confirmed in previous studies. However, during the fluctuation of the magnetic cluster, due to changes in its angle to the workpiece and the strength of the magnetic field, it will cause changes in the finishing force, which will affect the material removal. Therefore, in order to further improve the finishing efficiency, this study used full-wave rectified current (F-AC) to change the fluctuation behavior of the magnetic cluster. Specifically, the effect of changing the current waveform on the fluctuation behavior of the magnetic cluster is observed. Simultaneously, the effects of current waveform changes on finishing characteristics are analyzed in combination with experiments. As a result, using F-AC can make the fluctuation range of the magnetic cluster smaller, and the average finishing force can be improved. In addition, F-AC is very helpful to improve the finishing efficiency when smaller magnetic particles are used.

In order to improve processing efficiency of the magnetic abrasive finishing (MAF) process, the magnetic abrasive finishing combined with electrolytic (EMAF) process was proposed and the feasibility was proved in previous study. Because the relation among the flow field (electrolyte), the electric field and the magnetic field is very complicated during the EMAF processing, the processing mechanism that has not been fully explored. In this study, the interaction between the amount of electrolytic iron powder and the electrolytic reactions was preliminarily explored. The stability of the EMAF processing is evaluated by the measured processing current value curve. By observing the status of electrolytic iron powder and comparing the processing results, the factors that affect the processing stability were found out. Through a series of exploratory experiments and analysis, the results show that excessive iron powder will cause unstable processing current and weaken the processing effect of the electrolytic reactions in EMAF Processing. At the same time, the changes of iron powder particle size before and after processing was further observed. The best results were obtained when using the electrolytic iron powder of 330 μm (in mean diameter) and the supply amount of 0.6 g.

Magnetic abrasive finishing (MAF) is a precision surface polishing method, and it has been widely used in semiconductors, optics, aerospace industry, etc. At present, most studies on planar MAF are focused on improving the surface roughness accuracy. In practical applications, the initial surface of the workpiece is both rough and convex or concave. While the traditional processing method improves the surface roughness accuracy, the original surface is hardly unchanged. This paper proposes a finishing method of variable speed in different regions based on the initial surface of workpiece. According to the characteristics of the magnetic brush is distributed on the edge of the magnetic pole, it is regarded as composed of two left and right half circles. During the processing, the left and right parts will process twice at the same position of the workpiece. The finishing method in this paper makes the total processing time longer where the initial surface is high, while the total processing time is shorter where the initial surface is low, thereby achieving the purpose of improving the surface smoothness. This paper also verified the feasibility and effectiveness of this method through simulation and experiment.

In order to solve the problems such as the easy deformation and poor recovery of magnetic brush in conventional magnetic abrasive finishing method, a new magnetic abrasive finishing method has been proposed in this study. By using alternating current, the coil can produce alternating field in magnetic circuit. Since alternating magnetic field, the magnetic particles can form magnetic brush periodically that can keep it having a good shape during finishing process. From theoretical formulas, the relationship of the frequency between alternating current and alternating magnetic force is investigated. The results are the same with the measure results. At last, a multi-stage finishing experiment is performed with the alternating magnetic field abrasive finishing process. There are two steps in this finishing, rough finishing and ultra-precision finishing. The results show that surface roughness can be improved from 230 nm Ra to 19 nm Ra in 60 minutes.

In previous studies, it has been proved that the process of interior magnetic abrasive finishing using a magnetic machining tool is effective in improving the shape accuracy (roundness) of thick SUS304 stainless steel tube. But the mechanism of the improvement is undefined. In this paper, mainly discussing the improvement of interior roundness of the thick SUS304 stainless steel tube by dynamic and trajectory analysis. In particular, the factors affecting the improvement of interior roundness of the thick tube was studied by discussing the reciprocating velocity of magnetic pole unit. Firstly, the force analysis diagram of the magnetic machining tool in the model doing uniform rotational motion was performed. Secondly, according to the dynamics, dynamic equation of the magnetic machining tool was discussed. And then, the motion model of trajectory of the magnetic machining tool was discussed. Finally, the three reciprocating velocities of magnetic pole unit were compared in the experiments. The results correspond to the discussion that lower reciprocating velocity of magnetic pole unit is beneficial to the improvement of interior roundness.