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Jia Y.,Beijing Institute of Electro Machining | Jia Y.,Beijing DMBEST Tool Technology Co.
Advanced Materials Research | Year: 2012

The electrode material is playing the very important role in the electrical discharge machining. Two kinds of electrode materials common used in EDM are compared and analyses similarities and differences in structure and physical characteristics. Combined with PcBN tool machining tests, from the electric discharge machining efficiency, electrode wear, tool surface quality, tool surface degenerating layer, machining results are in analysis and comparison, and then different electrode materials machining technics in electrical discharge machining process are summarized. Through the cutting tool electric discharge machining experiments, we can know that the graphite electrode easy to take shape, suits in the complex edge's cutting tool electric discharge machining, under the same electric discharge machining parameter condition, its processing efficiency must be higher than the copper electrode, but the electrode loses, the cutting tool surface quality and affect layer thickness are to be worse than the copper electrode.


Zhang H.,North China University of Technology | Wang L.,North China University of Technology | Liu J.,Beijing Institute of Electro Machining
Zhongguo Jixie Gongcheng/China Mechanical Engineering | Year: 2016

For the problems of the low energy utilization of conventional pulse generator, the resistors overheating and huge cooling equipments, a kind of EDM pulse generator was presented herein, which cancelled the current limiting resistors. The pulse generator was made up of a PWM controller, a DC/DC converter, a machining pulse sequence generator and so on. It could automatically adjusting the output voltages, and the no load voltages, pulse width and pulse interval were adjustable in a wide range. The bulky frequency transformer was cancelled in the pulse generator. The experimental curves of the electrode wear rate, small holes' ovality and one-side discharge gaps were obtained by the multiple small hole machining experiments. The experimental curves were closely related to the stability of the pulse generator. These data show that the pulse generator has good stability and reliability. © 2016, China Mechanical Engineering Magazine Office. All right reserved.


Jia Y.H.,Beijing Institute of Electro Machining
Applied Mechanics and Materials | Year: 2014

The electrode material plays a very important role in the electric discharge machining, affects the electrical discharge machining efficiency and machining surface quality. Experiment testing and materials analysis as the primary method, affect layer thickness and workpiece surface roughness value as evaluation indexes. PCD cutting tool samples were electrical discharge machined using copper electrodes and graphite electrodes respectively. After machining, the PCD cutting tool samples' surfaces were analyzed by X ray diffraction, the surfaces appearances were observed under the scanning electron microscope, and the surface roughness values were measured by roughness measuring instrument. PCD samples' surface effect layer thickness values and surface roughness values, affect layer distribution structure was statically analyzed in typical EDM process conditions with different electrode materials. Summary electrode material effect on PCD cutting tools in EDM processing. Provides an important experimental basis for designing technics of precision and highly efficient electrical discharge machining PCD cutting tools. © (2014) Trans Tech Publications, Switzerland.


Jia Y.H.,Beijing Institute of Electro Machining | Guan C.Z.,China Unicom
Industrial, Mechanical and Manufacturing Science - Proceedings of the 2014 International Conference on Industrial, Mechanical and Manufacturing Science, ICIMMS 2014 | Year: 2015

Electrical discharge grinding is one of the most widely used methods to machine polycrystalline diamond compact cutting tool. It is a type of self-excited pulsed electric discharge machining process based on the principle of discharge erosion. Polycrystalline diamond compact samples with different crystal granularity are the research object. Electrode rotating speed, open-circuit voltage, peak current are selected as the main process parameters. The material removal volume and electrode loss set as the evaluation index of productive efficiency;workpiece surface roughness value sets as an evaluation standard of processing quality.With electrical discharge grinding experiments, combined with scanning electron microscopy observation and roughness tester, the influences of the main process parameters on electrical discharge grinding are analyzed. Polycrystalline diamond compact electrical discharge grinding process is summarized. © 2015 Taylor & Francis Group, London.


Jia Y.,University of Science and Technology Beijing | Jia Y.,Beijing Institute of Electro Machining
Applied Mechanics and Materials | Year: 2012

Multi-plate wet friction clutch is one of key components of duty truck hydrodynamic-mechanical transmission. Super-heated burn and warping deformation are main invalidation forms of wet friction clutch. It is one of effectual methods to augment friction coefficient and prolong natural life of wet friction clutch that friction disks' surface temperature and radial temperature are reduced. Compute method of friction disk surface temperature is obtained using theory analysis and confirmed correctness using finite element analysis. It is salience character of wet friction clutch that there are some oil grooves in friction disk surface. These oil grooves can increase friction coefficient and emanate heat quantity. Confirming conformable friction disk's surface oil groove configuration by experiment research is received. It confirmed that the appropriate surface oil groove configuration of friction disk should be double-arc groove. © (2012) Trans Tech Publications, Switzerland.


Jia Y.,Beijing Institute of Electro Machining
Applied Mechanics and Materials | Year: 2012

The samples of Polycrystalline cubic boron nitride (PcBN) cutting tool were machined by adjusting the main parameters of electrical discharge machining (EDM). After the machining, the phases were analyzed by X-ray diffraction analyzer and the surface layer microstructure was observed by scanning electronic microscope. The fundamental component of machined PcBN cutting tool affected layer was obtained and the reason of begetting affected layer was analyzed. The relationship curves between pulse width, working electric current and thickness of affected layer, blade surface roughness were summarized. The relationship between PcBN cutting tool's life that was machined by EDM and cutting tool flank width, workpiece surface roughness were analyzed. The results showed that to adjust electrical discharge machining parameters, such as decreasing pulse width or machining electric currents, can reduce the thickness of affect layer, improve blade surface roughness and extend the service life of PcBN cutting tool. These researches provide valuable test reference for drawing up electrical discharge machining technics of PcBN cutting tool and forecasting cutting tool's life.


Jia Y.,Beijing Institute of Electro Machining
Jingangshi yu Moliao Moju Gongcheng/Diamond and Abrasives Engineering | Year: 2015

Polycrystalline cubic boron nitride (PCBN) compact samples with different grain size are processed. Electrode running speed, open-circuit voltage, peak current, pulse width and pulse interval were selected as the main process parameters. The material removal volume and electrode loss were set as the evaluation index of production efficiency; workpiece surface roughness value was set as evaluation standard of processing quality. By electrical discharge grinding experiments, combined with scanning electron microscopy observation, energy spectrum analyzer and roughness tester, the influences of main process parameters on electrical discharge grinding were analyzed. So were polycrystalline cubic boron nitride compact electrical discharge grinding technics & mechanism. The research indicated that PCBN machining in EDG process was to melt bond at high temperatures, which resulted in PCBN particles falling off and realized material removal. This process was accompanied by element replacement and oxidation. PCBN particle size has less effect on efficiency and quality of electrical discharge grinding than electrical discharge process parameters. With the increase of the electrode rotation speed or open-circuit voltage, material removal volume of the workpiece and electrode loss both increased. With the increase of the peak current, material removal volume and surface roughness value of workpiece increased, but electrode loss decreased. ©, 2015, Zhengzhou Institute of Abrasives Grinding. All right reserved.


Jia Y.,Beijing Institute of Electro Machining
Advanced Materials Research | Year: 2011

High deformation hardening, low thermal conductivity, high built-up edge tendency of austenitic stainless steels were the main factors that make their machinablity difficult. For determination of the suitable cutting parameters in machining austenitic stainless steel by PcBN cutting tools, the samples which were prepared to be used in the experiment, 300 mm in length and 60 mm in diameter, were dry machined in a numerical control lathe. During experiments, dry turning parameters, such as feed rate, cutting speed and cut depth were investigated. The suitable cutting speed and feed rate were determined according to workpieces surface roughness, cutting tools flank wear. Finally, cutting speed of 160 to 200 m/min, feed rate of 0.06 to 0.08 mm/rev and cut depth of 0.10 mm gave the satisfied results. © (2011) Trans Tech Publications.


Jia Y.,Beijing Institute of Electro Machining
Advanced Materials Research | Year: 2012

High deformation hardening, low thermal conductivity, high built-up edge tendency of austenitic stainless steels were the main factors that make their machinablity difficult. For determination of the suitable cutting parameters in machining austenitic stainless steel AISI 304 by PcBN cutting tools, the samples which were prepared to be used in the experiment, 300 mm in length and 60 mm in diameter, were dry machined in a numerical control lathe. During experiments, dry turning parameters, such as feed rate, cutting speed and cut depth were investigated. The suitable cutting speed and feed rate were determined according to workpieces surface roughness, cutting tools flank wear. Finally, cutting speed of 180 to 200 m/min, feed rate of 0.05 to 0.06 mm/rev and cut depth of 0.10 mm gave the satisfied results. © (2012) Trans Tech Publications, Switzerland.


Jia Y.-H.,Beijing Institute of Electro Machining
Jingangshi yu Moliao Moju Gongcheng/Diamond and Abrasives Engineering | Year: 2013

The electrode plays a very important role in the electric discharge machining, affecting the electrical discharge machining efficiency and machining surface quality. Two kinds of electrode materials commonly used in EDM are compared and analysed on similarities and differences of the structure and physical characteristics. Taking tests and materials analysis as the primary methods, affect layer thickness and workpiece surface roughness value as evaluation indexes, PCD cutting tool samples were machined using copper electrodes and graphite electrodes respectively. After machining, the PCD cutting tool samples' surfaces were analyzed by X-ray diffraction. The surface appearences were observed under the scanning electron microscope, and the surface roughness values were measured by roughness measuring instrument. PCD samples' surface affect layer thickness, surface roughness values and affect layer distribution structure were statically analyzed in typical EDM process conditions with different electrode materials. The electrode material effect on PCD cutting tools in EDM processing are summaried, providing an important experimental basis for research on the mechanism of precision and high efficient electrical discharge machining PCD cutting tools.

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