Papers by Author: Wen Ji Xu

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Authors: Wen Ji Xu, Gui Bing Pang, Jian Cheng Fang, Xieeryazidan Adayi, Xu Yue Wang
Abstract: Taking plate as the example, this paper studies the effect of tool’s shape and movement on the electrochemical as well as mechanical lapping characteristics in Electrochemical Abrasive Lapping (ECAL). It is assumed that the removal size of electrochemical action at a random point is in direct proportion to the electrical amperage through this point and the removal size of the lapping action is in direct proportion to the relative frictional distance. Based on the assumption above, electrochemical and mechanical lapping characteristics with different tools shape are studied theoretically. The results show that the diameter of the tool should be larger than the width of the workpiece when a discal tool is used and the inner diameter of the tool should be larger than the width of the workpiece when a ringed tool is used, on the other hand the ratio of the revolving radius of the tool to the diameter of the tool as larger as possible avails to improve the precision and so does the ratio of the angular velocity of the workpiece to the rotating angular velocity of the tool.
374
Authors: Wen Ji Xu, Jian Cheng Fang, T. Wang, F. Liu
Abstract: To solve the difficult problem of selecting processing parameters of plasma arc cutting ceramic (PACC), the heat conduction model of PACC has been established and the calculating formulations of temperature field have been derived. Then, the distributions and influence factors, such as arc power, cutting speed and workpiece thickness, of temperature field of the ceramic plate and the anode plate have been studied. Based on the work above, the required arc power can be calculated. Moreover, the relation between thickness of ceramic plate and anode plate can be determined, which provides a helpful reference for selecting the thickness of additional anode plate.
1811
Authors: Jian Bing Meng, Wen Ji Xu, Jing Sun, Xu Yue Wang, L.J. Wang
Abstract: A theoretical analysis was carried out to investigate the characteristics of plasma arc injected transverse to a transverse-alternating magnetic field. Two mathematical models were developed to describe both the oscillating amplitude of the plasma arc root and the heat flux density distribution of plasma arc on the workpiece surface. The characteristic of plasma arc under the external transverse-alternating magnetic field imposed perpendicular to the plasma current was discussed. The effect of processing parameters, such as working gas flux, arc current, magnetic flux density and the standoff from the nozzle to the workpiece, on the oscillation and heat flux distribution of plasma arc were also analyzed. The results show that it is feasible to adjust the shape and heat flux density of the plasma arc by the transverse alternating magnetic field, which expands the region of plasma arc thermal treatment and uniforms the heat flux density upon the workpiece. Furthermore, the oscillating amplitude of plasma arc decreases, and the heat flux density gradient upon the workpiece increases with decrease of the magnetic flux density. Under the same magnetic flux density, more gas flux and more arc current cause the oscillating amplitude to decrease. The researches have provided a deeper understanding of adjusting of plasma arc characteristics.
1222
Authors: Wen Ji Xu, Jian Cheng Fang, F. Liu, Gui Bing Pang
Abstract: For the development of flexible forming using plasma arc (FFUPA), it is extremely necessary to investigate the forming rules of curvilinear scanning and multipath combined scanning. In this paper, the difference between circular scanning and linear scanning and the influence of sheet metal geometry on forming effect have been discussed. In the experiments, circle, ring and rectangle mild steel sheets with thickness of 0.8mm are taken as workpieces and the experimental results show that nonlinear prolonged surface can be obtained by curvilinear scanning and there exists the obvious difference between circular scanning and linear scanning. Afterwards, the reason of the difference mentioned above is concisely analyzed. Finally, some suggestions are presented for the future investigation.
3943
Authors: Ze Fei Wei, Wen Ji Xu, Gui Bing Pang, Xu Yue Wang
Abstract: In this paper, surface topography characteristics of electrochemical mechanical finishing (ECMF) for steel was investigated. The scanning electron microscopy (SEM) was used to observe the surface topography. And the microcosmic geometry parameters were measured by Talysurf SLI2000. Compared with original surface, the surface topography characteristics of the workpiece machined by ECMF have been analyzed with altitude density function (ADF) and auto correlation function (ACF). The results show that there exist periodicity component in surface profile before and after finishing. The auto correlation curves of ECMF surface have a smaller average period compared with grinding surface. The low-frequency component and the mean ripple peak distance of original surface profile are obviously decreased. Furthermore, the ripples and peak density are increased, and the surface roughness Ra is decreased from 0.231μm to 0.023μm. The results indicate that surface quality, material ratio of the profile and wear resistance machined by ECMF are improved obviously.
658
Authors: Jing Sun, Wen Ji Xu, Dian Long Wang
Abstract: All countries of the world carry forward progress in engineering education reform actively to meet the keen demand of innovative engineering talents which results from the global industry development, the source from which the global engineering excellence research project stems. Firstly, this paper reviews the origin and prophase research results of exemplary engineering innovators (EEI) research project. Secondly, this paper provides a systematic and comprehensive introduction to the industry-oriented EEI cultivation mode for bachelor’s degree engineering practiced in Mechanical Design & Manufacturing and its Automation of Dalian University of Technology based on an analysis of the cultivation actuality of EEI. Finally, this paper puts forward advices to form EEI cultivation mode with Chinese characteristics.
1671
Authors: Wen Ji Xu, Jian Cheng Fang, F. Liu, Xu Yue Wang, Zhi Yu Zhao
Abstract: Flexible forming using plasma arc (FFUPA) is a newly developed method of sheet metal forming. It makes the forming by means of thermal stress and thermal strain without mould and die, and is recognized as a promising forming method in developing new products. But the forming effect of FFUPA is determined by many factors, which compose a highly nonlinear system due to their complicated interact. As a result, it is difficult to predict the forming results and choose the processing parameters in FFUPA. In this paper, BP neural network is applied to solve this problem. After introducing the mechanism of FFUPA and analyzing the influence of processing parameters on the forming result, BP neural network is established, which include an input layer, an output layer and a hidden layer. When inputs and outputs are properly chosen, the BP neural network can be used to predict the forming results and to select the forming parameters. To verify the validity of this network, the results obtained by the BP neural network are compared to those obtained by experiments, and the results show that the former is close to the later, which indicates it is feasible to apply BP neural network in determining the processing parameters and forecasting the bending effects in FFUPA.
615
Authors: Jing Sun, Wen Ji Xu, Chun Yan Wang
Abstract: The image collecting devices, which consist of optical lens, neutral density filter, narrow-band interference filter, CCD and the other equipments are set up to collect the images of plasma arc column with and without external transverse alternating magnetic field (ETAMF). On the basis of de-noising and enhancing morphological characteristics to the collected images, the characteristics of plasma arc with and without ETAMF are analyzed comparatively. The results show that the application of ETAMF is capable to get oscillation of plasma arc, and change its location, shape and heat flux density distribution, which can get efficiently control in the width of heated area and flatten heat flux density of workpiece surface.
1812
Authors: Wen Ji Xu, Bin Tao, Gui Bing Pang, Xu Yue Wang, Xiao Hui Zhao
Abstract: This paper researches on the theory of the crown modification of cylinder-roller bearing raceway using electrochemical abrasive belt grinding (ECABG) technology, and establishes relevant experimental device. The range of processing parameters with a better surface roughness can be obtained through experiments. On this basis, a mathematics model of distribution of material removal of electrochemical machining bearing is set up. Considering the controllability of processing parameters and demand of the surface quality, the processing parameters such as interelectrode voltage, electrolyte, interelectrode gap and cathode geometry are invariable in the experiment, and processing time is changed to control the crown value. The experimental results show that ECABG can enhance the surface quality of raceway to a great degree, and obtain the ideal forming crown at the same time under the optimum technological parameters. This paper developed a new method for the crown processing and finishing of bearing raceway.
335
Authors: Jian Bing Meng, Xiao Juan Dong, Wen Ji Xu
Abstract: A theoretical analysis was carried out to investigate the characteristics of atmospheric pressure plasma arc injected transverse to a transverse alternating magnetic field and a mathematical model was developed to describe the heat flux density distribution of the plasma arc. The effect of processing parameters, such as flow rate of working gas, arc current, magnetic flux density and the standoff from the nozzle to the workpiece, on the heat flux density distribution of plasma arc were also analyzed. The results show that it is feasible to adjust the heat flux density of the plasma arc by the transverse alternating magnetic field, which can expand the region of plasma arc thermal treatment and flatten the heat flux density upon the workpiece. With the magnetic flux density enhancing, the heat flux density gradient upon the workpiece decreases. Under the same magnetic flux density, the more gas flow rate and arc current, the more heat flux density peak increase. Contrarily, more distance from nozzle outlet to workpiece descends the heat flux density peak.
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