Papers by Author: Xi Peng Xu

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Authors: Q.L. Han, Yuan Li, Xi Peng Xu
Abstract: In this paper, an experimental study was conducted to compare the sawing of granite with thin and normal blades. The power drawn by the spindle and horizontal and vertical forces were measured. The width of sawing slot on the granite was examined after sawing. For both blades, power and forces increase with the depth of cut. The width of sawing slots for the thin blade was about 75% of the normal blade. The width of sawing slots for either thin or normal blade sawing became narrower in larger depth of cut.
Authors: Yi Qing Yu, Yuan Li, Xi Peng Xu
Authors: Shu You Zheng, Xi Peng Xu
Abstract: Ultrasonic machining has been proven to be a promising machining method on hard and brittle materials. However, due to the absence of high power ultrasonic machine tools, reported studies on ultrasonic machining were mainly concerned of relatively small hole drilling of the given materials. In the present work, with the development of the higher power Rotary Ultrasonic Machine Tool, two kinds of ultrasonic face machining with free abrasives, namely, Non-rotating Ultrasonic Machining with Free Abrasives (NRUSM) and Rotary Ultrasonic Machining with Free Abrasives (RUSM) are designed and comparatively conducted for the red granite, which is a typical hard-to-machine natural material. The effects of static force, spindle speed and amplitude of ultrasonic vibration on the performance of the machining are evaluated in terms of the material removal rate and surface quality. Experimental results indicate that ultrasonic machining is effective for face milling of the stone material with the designed machine tool. Furthermore, machining performances in RUSM are superior to those in NRUSM.
Authors: Jun Feng Gong, Xi Peng Xu
Abstract: In this paper, the 3D morphology of a grinding wheel was modeled by the depth from focus. Firstly, the picture information of different heights was extracted by the up-down moving of the microscope. The operator Laplacian was adopted to distinguish the distinct and fuzzy areas in a picture. Then, the distinct image and height information was obtained. The information of height was distorted due to the occurrence of noise. In order to reconstruct 3D surface, a method based on Min/Max curvature flow was developed to remove noises. In the end, an abrasive grain in the image of a grinding wheel was segmented by the Mumford-Shah model. The results could be further developed to evaluate the worn status of grinding wheels. Introduction The examination of the wear of abrasive grain in the grinding wheel is very important for evaluation of performance of diamond grinding wheel. The three-dimensional (3D) reconstruction of grinding wheel topography can provide more information about wear of abrasive grains than common ways such as observation by optical microscope. Nowadays, there have been many techniques to be considered to obtain 3D data, for example, profilometry, the scanning electron microscope (SEM), the scanning laser microscope (SLM), stereo vision and so on. SEM is a powerful measuring tool, but the time needed for sample coating process and chamber air pumping is considerable. SLM is promising tool for 3D shape modeling, but still expensive for most of users. Stereo vision is simple and quick method to obtain the height information, but only the height of points which match in two corresponding images could been obtained. In this paper, a new method based on depth from focus (DFF) [1] is presented for 3D modeling. Compared with SEM and SLM, it is easy and not very expensive equipments are needed. Meanwhile, it can provide more real 3D model than stereo vision method. In order to measure the abrasive grains, a segmentation Algorithms based on Mumford-Shah model [4] is introduced to divide the grains from image of grinding wheel.
Authors: Fang Yi You, Jian Yun Shen, Xi Peng Xu
Abstract: In the present study, grinding temperature was measured by using a foil thermocouple when granite was ground by SiC wheel. De-noised the temperature signals with soft threshold method base on wavelet transform was conducted to analyze the grinding process. Energy partition to workpiece was estimated to be about 10%~30% by matching the measured temperature to analytically value. The number of active grains was determined by counting the high frequency impulses in the measured temperature signals. The ratio of active grains to total grains was about 4.5%~6.1%. Based on the results, a formula was deduced for calculating the temperature of single grain in the grinding process.
Authors: Chang Biao Huang, Kai Yong Jiang, Xi Peng Xu
Abstract: In this paper COM+ based on Microsoft .NET is adopted to realize a Distributed Collaborative System (DCS). This system adopts a complex architecture combined C/S with B/S to reduce the remote communication and improve the performance. By means of IE or other browsers, a client can download client tool, register or login, search or publish information via the collaborative website. After installing the client tool, a client can automatically receive the collaborative requests or invitations from the collaborative server and collaborate with other participators. The system utilizes COM+ services to realize the Distributed Synchronous Communication (DSC) and Distributed Asynchronous Communication (DAC). Loosely Coupled Event (LCE) service can make DSC true easily and effectively. Transaction service, Queued Component (QC) service and Windows NT Service can be applied to realize DAC efficiently and reliably.
Authors: Juan Liu, Hui Huang, Xi Peng Xu
Abstract: In this paper, the influences of abrasive size, abrasive concentration and admixture way on the abrasive dispersing of the sintered ultra-fine diamond tool were systemically investigated. Then, a comparison of the abrasive dispersing was made between the sintered ultra-fine diamond tool and the newly developed ultra-fine diamond tool by gel technique. ESEM was applied to observe the abrasive dispersing of the sintered and gel-coupled ultra-fine diamond tools. The abrasive dispersing was quantitatively evaluated by the statistic laws of grit spacing in a certain area. Experimental results indicated that the dispersing was mainly influenced by the abrasive size. The ultra-fine abrasive tended to agglomerate with the decrease of grit sizes due to the increase of surface energies. The abrasive concentration and admixture way had few effects on abrasive dispersing. The abrasive dispersing of the sintered diamond tool was worse compared with the gel-coupled ultra-fine diamond tool.
Authors: Xin Xiang, Jiang Quan Wang, Jian Yun Shen, Xi Peng Xu
Abstract: An investigation is reported of the relationships of the temperatures and grinding parameter for grinding of ceramics with a brazed diamond grinding tool. During the experiments, the temperature distributions along the workpiece surface were measured using a foil thermocouples and the energy partition to the workpiece estimated using a temperature matching method. The results show that the grinding temperature increased with the increasing of worktable feed rate or tool velocity and depth of grinding. The measured temperature responses were found to be in good relation with the analytical results of a moving heat source with a rectangular distribution at the grinding zone.The energy partition ε is about 23%.
Authors: Yi Qing Yu, Yuan Li, Xi Peng Xu
Abstract: An investigation is reported of the characteristics of specific energy in grinding of granite using diamond abrasives. The effects of many parameters, such as the types of diamond tools, the types of abrasives, the properties of granite, the conditions of lubrication, and the working conditions of diamond tools, were studied. The power consumed in grinding was measured in order to obtain the specific energy, which is defined as the energy expended per unit volume of material removal. It is found that the specific energy for grinding of granite was closely related to the removal mechanisms of granite, the failure modes of diamonds and the interactions of the swarf with the applied fluid and bond matrix.
Authors: Guo Qing Zhang, Hui Huang, Xi Peng Xu
Abstract: An experimental investigation was carried out to braze diamond abrasives onto thin steel wires, in which case the brazing was conducted in the vacuum and under high temperatures by using a nickel-based powder as brazing alloy. The morphologies and microstructures of the brazed wires were observed and the comprehensive mechanical properties of the brazed wires were tested. The brazed wires were also used to cut such brittle materials as ceramics, glass, and natural stone. It is shown that a typical phenomenon of brazing alloy’s climbing around the diamond grains was observed in brazing the wires. Through observing the cross-section of brazed wires, it is observed that there is a good bonding between the brazing alloy and the body of steel wires. The crystal grains of the steel wires grew significantly after brazing. Through observing the morphologies of the diamond wires and the surfaces of four workpiece materials, few diamond pull-outs were found on the wires and the kerfs on the workpiece materials were basically flat.
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