Papers by Keyword: Electrochemical Machining (ECM)

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Authors: Fatih Sahin, Fırat Kafkas, Cetin Karatas
Abstract: Residual stresses play an important role in the performance of materials and the components produced from them. All manufacturing processes introduce residual stresses. These stresses can have a positive effect, for example by increasing the fatigue limit in the case of compressive surface residual stresses. Layer removal by electrochemical machining (ECM) can be used for measurement of the residual stresses in the PM parts. The device removed the layers by aid of electrochemical machining for this purpose is designed and developed. The device setup for residual stress measurement is based to the changes on deformation quantity. Since ECM is a non-mechanical metal removal process, ECM is capable of machining any electrically-conductive material with attendant high removal rates, regardless of mechanical properties. In particular, the removal rate in ECM is independent of the hardness, the porosity and toughness of the PM parts being machined. The micro constituents in PM steels resulting from different processing routes exhibit different thermal and mechanical behavior. This will lead to the formation of residual stresses around these micro constituents. Here we give the results of the first work carried out on PM steels in relation to residual stress measurements by the electro-chemical layer removal technique. The device works as follows. As a layer of thickness is removed, a certain amount of stress is removed from the sample. Equilibrium is violated and the sample deforms elastically to compensate for the stress removed. This elastic deformation in the sample is measured by the linear displacement gauge. This gauge pushes on the end of sample and deformation is recorded by this gage. The linear gauge send a signal to a display and then to the data converter. As simultaneous, this signal sent to the computer from the data converter for further calculations by RS 232.
Authors: Yuan Yuan Ge, Fu Yuan Wang, Ai Mei Zhang, Su Tao Zhuang
Abstract: In this paper, in order to make the simulation of the whole process of electrochemical machining(ECM), the characteristic of electric field and flow field is made detailed analysis in the gap of ECM. Mathematical-physical models of ECM simulation is set up based on the basic theories of electrochemistry, electric field and flow field. And the method of model solution is discussed and researched. So the theoretical base is established of the full process of ECM simulation.
Authors: Ji Hua, Zhi Yong Li
Abstract: Cathode design is a difficult problem must be faced and solved in ECM. We develop a new numerical approach for cathode design by employing a finite element method and this approach has been applied in the cathode design of aero-engine blades in ECM. The mathematic models of the electric filed and electrolyte flow filed distribution in EMC process are described primarily. Then the realization procedure of this approach is presented,in which the effects of electric filed and electrolyte flow filed distribution within the inter-electrode gap domain are concentrated. In order to verify the machining accuracy of the designed cathodes, the experiments are conducted using an industrial scale electrochemical machining system. The experimental results demonstrate that the machined blade have high surface quality and dimensional accuracy which proves the proposed approach for cathode design of aero-engine blades in ECM is applicable and valuable.
Authors: Dan Dan Li, Zhi Jian Fan
Abstract: The long spiral tube with its deep rifle groove make a long duration for Electrochemical Machining (ECM) and mass of floccule precipitate, esulting in bottleneck to maintain cleanliness of electrolyte in sedimentation basin at machining. The design scheme of duplex vertical flow electrolyte basin was proposed. The surface hydraulic power, available cubage, flooding area, sludge blanket level (SBH) and sludge tank height were calculated in terms of the electrical current, sinking speed of Fe(OH)3, flux of electrolyte. The streamline in the basin were simulated by COMSOL based elementary draft. The flow speed at intake of sludge blanket and the exit of clarified were analyzed with diameter of cone-meatus of center tube being altered and the space between it and baffle-board shifted, and the sedimentation basin is optimized.
Authors: Fırat Kafkas, Çetin Karatas, Suleyman Saritaş
Abstract: The characteristics of residual stresses occurring in PM steel based nickel (FLN2-4405) was investigated. Residual stresses were measured by electrochemical layer removal technique. The values and distributions of residual stresses occurring in PM steel processed under various densities (6.8, 7.05, 7.2 and 7.4 g/cm3) and heat treatment conditions (sintered at 2050 ºF, sintered at 2300 ºF, quenching-tempered, and sinter-hardened) were determined. In most of the experiments, tensile residual stresses were recorded on the surface of the samples. The residual stress distribution on the surface of the PM steels was found to be affected by the heat treatment conditions and density. The maximum values of residual stresses on the surface showed sinter hardened condition and a density of 7.4 g/cm3. The minimum level of recorded tensile residual stresses are150 MPa and its maximum level is 370 MPa.
Authors: Manabu Iwai, Wen Qiu Wei, Shinichi Ninomiya, Sadao Sano, Tetsutaro Uematsu, Kiyoshi Suzuki
Abstract: In order to realize electrochemical finishing in tap water, an ultrasonic vibration using a transducer enabling three kinds of vibration modes, i.e., axial, bending, and complex, was given to the electrode. During the test finishing, it was observed that with electrode without ultrasonic vibration, the workpiece surface was simply covered with the rust. On the contrary, by applying the ultrasonic vibration of bending vibration mode or complex vibration mode with an appropriate amplitude, the material removal rate was increased and the surface roughness was improved.
Authors: Ping Mei Ming, Di Zhu, Zheng Yang Xu
Abstract: The electro discharge machining (EDM) process is widely applied to produces surfaces of difficult-to-machine materials that require some form of grinding or finishing operation. This is conducted so as to improve the surface texture and appearance of the component’s surface. However, it is also desirable to remove the white uppermost recast layer or damaged surface layer (produced by the EDM process) in order to improve the functional performance of the surface. The finishing of the surface by traditional manual methods, especially in the operation of small and long internal cylinder surface, is both tedious and time-consuming. A novel electrically conductive diamond mounted point electrochemical grinding (DMP-ECG) process is being developed for hard passive alloys unclosed internal cylinder surface grinding. The process mechanism of DMP-ECG is introduced; the influence parameters of the surface roughness, machining accuracy, and diamond tool wear are investigated experimentally for nickel-based super alloys materials. An application of the DMP-ECG to aircraft engine component is verified in term of the optimized process parameters.
Authors: Ming Huan Wang, C.Y. Yao, Qiao Fang Zhang, Wei Peng
Abstract: Electrochemical machining (ECM) technology has the advantage of machining the workpiece with complex profile on the basis of electrolysis. In this study, turbulated holes with the rib’s shape of spiral and annular were processed by ECM by using the shaped cathodes. Experimental system was built which consists of electrolyte supply module, power supply unit and workpiece holding device. Machining experimentations were carried out on the built system. Analysis and discussions were done according to the experimental results. It indicated machining efficiency is high by using the shaped cathode. Machining error could be controlled within 10-20%.
Authors: Zhuang Liu, Z.J. Qiu, C. Heng, Ning Song Qu
Abstract: ECM micro drilling with tool electrode jump motion in cycles is introduced in this work. A linear motor is employed to carry tool to jump with high acceleration in cycles. Due to the high accelerating motion of tool electrode, the electrolyte within machining gap is able to be refreshed. The Z-axis feeding motor, linear motor and DC supplier are coupled in the experimental setup and a series of micro-holes are drilled on stainless steel (1Cr18Ni9Ti) plate with thickness of 0.5mm to investigate the presented process. Experimental results shows, cycle jump motion of tool electrode, higher jump acceleration, longer jump height and shorter cycle machining time lead to better machining accuracy.
Authors: Li Xin Yuan, Jia Wen Xu, Jian She Zhao
Abstract: Laser beam machining is often associated with the metallurgical defects related with spatter, recast layer and heat-affected zone. In order to overcome the defects, this paper presents a process of jet electrochemical machining and guided laser beam machining (JECM-GLBM). On the explain of experimental principle and apparatus, jet electrochemical machining and laser beam machining(JECM-LBM) and JECM-GLBM experiments have been performed on 0.5mm thick 321S20 stainless steel under the same experimental condition respectively. The experimental results show that the entry circularity, repeatability and the surface quality of JECM-GLBM are significantly better than JECM-LBM, and the spatter and the recast layer of hole-wall has been mostly removed in JECM-GLBM. In addition, increasing the IEG leads that the taper and overcut are decreased in JECM-GLBM. By analyzing the experimental results, the best IEG is 10mm, which is unusually beneficial for the design of equipment in engineering application.
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