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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. Source


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. Source


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. Source


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. Source


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. Source

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