Abrasive flow machining (AFM) is an efficient means of deburring, surface polishing, and removing recasting layers from machined components. However, a smoother surface is not easily created after polishing since one-way motion of abrasive media in the traditional AFM. Therefore, this study designs a novel helical passageway to perform multiple flowing paths of an abrasive medium in order to reduce the surface roughness. There are several helical cores with different machining parameters have been performed to finish the circular holes; surface roughness uniformity and roughness improvement rates (RIR) are evaluated after AFM. The results indicate that a helical passageway performs better in reducing RIR by approximately 76%compared with a RIR of nearly 60%from the original circular passageway. In addition, the optimal design of helical cores includes a four-helix groove, a 0.5mm gap, a 0.5mm thickness of the helical slot and one helical turn. Based on experimental results, it is found that abrasive media in the helical passageways creates notable efficiency for good surface roughness and uniformity in the AFM process.

Since only uni-direction motion is produced by traditional abrasive flow machining (AFM), so the polishing effects of the inner hole is not easy to achieve uniform roughness of the whole surface after polishing. Therefore, in this study, a rotating device with a DC servo motor was set up in the AFM to increase the tangential forces on the machining surface, and therefore, improve the uniform surface roughness and polishing efficiency. The rotating device was designed by a group of transmission gear set and a DC servo motor to create a rotational finishing path for the abrasive medium. The rotational motion of an abrasive can create different tangential forces on the working surface, inducing a more complex polishing path than that of traditional AFM. In addition to rotational speed, a servo motor can also change rotation directions in one working process, causing an abrasive medium to create many irregular finishing paths in the AFM. The experimental results showed that the surface roughness of the workpiece was significantly decreased with an increase in the rotational speed. Additionally, the results also showed that the surface roughness (SR) of the inner hole decreased from 0.61 μm Ra to 0.082 μm Ra after 20 machining cycles, the surface roughness improvement rate reached 87% at 15 rpm rotational speed, by applying a 1.5:1 silicone gel/abrasive concentration ratio and #60 abrasive mesh in the experiments. This study created excellent polishing efficiency by using a servo rotational device with AFM to produce good surface quality.

Magnetic abrasive finishing (MAF) is a fast, high efficiency and high-precision polishing method on the surface machining of the metals. Furthermore, MAF also can be utilized to polish the stainless tubes in industrial applications; however, stainless tubes are often a non-magnetic material that makes it difficult for the magnetic field line to penetrate into the stainless tubes, thus reducing the magnetic forces in the inner tubes polishing. That is why stainless tubes are not easy to finish using traditional MAF. Therefore, magnetic finishing with gel abrasive (MFGA) applies gels mixed with steel grit and abrasives that were developed to improve the polishing efficiency and surface uniformity of the steel elements. In this study, a guar gum or silicone gel mixed with steel grit and silicon carbides are used as the magnetic abrasive gel to polish the stainless inner tubes. A DC motor was used to control the rotation speed of the chuck and an AC induction motor connected with an eccentric cam to produce the reciprocating motion of the workpiece were utilized to finish the inner surface of stainless tubes in the polishing process. The parameters of abrasive concentration, abrasive particle sizes, rotation speeds of motor and electric currents were used to investigate the surface roughness and the removal of materials from the stainless tubes. The experimental results showed that since guar gum had better fluidity than the silicone gel did, guar gum created excellent polishing efficiency in MFGA. Furthermore, the surface roughness of the stainless tube decreased from 0.646 μm Ra to below 0.056 μm Ra after processing for 30 min with the parameters of current 3A, gel abrasive with guar gum, rotational speed 1300 rpm and vibration frequency 4 Hz.

Magnetic gel abrasive finishing is a high-precision polishing method that uses magnetic forces to attract and restrain a gel abrasive, composed of aqueous slime gel, steel grits, and silicon carbon (SiC), for polishing workpieces. However, the magnetic adsorption performance of the gel abrasive will drop quickly when polishing non-ferromagnetic material such as stainless-steel or brass. Moreover, centrifugal force will push out the gel abrasive from the machining surface reducing the stability of polishing. Therefore, this paper developed a rotating cylinder-based magnetic finishing setup to allow the gel abrasive and workpieces to tumble and rotate together during the polishing process. To make the gel abrasive produce irregular and complicated movement paths for improving the polishing performance, this study first analyzed and compared the average surface roughness and removed material weight of workpieces using three kinds of motor operating modes; a unidirectional trapezoidal wave mode, a bidirectional sine wave mode, and a bidirectional trapezoidal wave mode. After identifying the best motor operating mode, the study further compared the polishing characteristics using several SiC particle and steel grit sizes. The experimental results showed that the rotating cylinder driven using a bidirectional trapezoidal wave could obtain better results for average surface roughness and removed material weight than the other two operating modes, while use of the larger steel grit size also obtained improved results. However, different silicon carbide particle sizes did not have a significant impact on the polishing characteristics.

This article presents an intelligent surveillance system based on stereovision for dynamic tracking of moving objects with autofocus and lossless zoom capabilities. The core technology of the system combines a modified stereovision algorithm with an autofocus search method. First, in order to reduce the effect of changing the lens focal length, the modified stereovision algorithm provides an obvious advantage in accuracy of depth estimation. Then the estimated depth not only can be used for adjusting the appropriate zoom level of cameras but also for shortening the search range of focal points. Moreover, the autofocus search method can simplify the image sharpness curve to a single peak. Therefore, by using spline interpolation, the focus position can be efficiently and accurately estimated. Finally, experimental results show that the proposed scheme has the ability to improve the accuracy of depth estimation and provide more clear images of moving objects.