| Cermet has a wide application prospects in Aeronautics and Astronautics, manufacturing, temperature measurement, petrochemical industry and so on due to their excellent material properties. Its application and promotion depend mostly on its process technology. However the application of the cermet has been greatly affected because of its character of high strength, high hardness and vulnerability. So it is urgent to settle the problem of cermet processing technology and significant to study the electrical discharge machining(EDM) technology of the cermet. On the basis of reviewing the status of research on cermet material and the EDM technology, from the aspects of processing surface microscopic characteristics, temperature field simulation and process test research, theoretical simulation and process experiment verification methods were applied in the study on the EDM of Ti C/Ni cermet in this paper.By analyzing the surface morphology and chemical composition of the EDM of Ti C/Ni cermet, the surface microstructure properties of Ti C/Ni have been researched, the influence of processing parameters on the erosion methods has been studied. It can be concluded that there is a significant differences on material erosion mode when the peak current is different, while pulse width changing only the degree of erosion effects without changing the type of erosion. Besides the formation of the surface melting solidified layer and surface crack of different processing regions have been analyzed and the measures to reduce cracks have been proposed.Build the randomly distributed simulation model of titanium carbide particles, through the temperature field simulation of Ti C/Ni cermet EDM single pulse discharge, the influence of peak current and pulse-on time on the pitting size of material is studied; The correctness of the simulation of the particle distribution model is verified by comparing the results of the simulation results with the unifo rm distribution of the materials. The material erosion rate and surface roughness model based on the single pulse discharge erosion were established, and it has been verified by relevant experiments.Influence rules of different process parameters such as positive and negative polarity, peak current, pulse-on time, pulse-off time on material removal rate, side gap and surface roughness of influence of is obtained by Ti C/Ni cermet single factor EDM process test. Conduct orthogonal test using peak current, pulse-on time, pulse-off time, servo voltage, servo speed and cycle of tool retraction as process parameters, and material removal rate, the side gap and surface roughness as the target of research process. By means of combination method of the signal-to-noise ratio and grey relational analysis, the orthogonal experiment results of the single objective and multi-objective were optimized and analyzed, and the optimal machining parameters combination scheme which met the requirements of various process objectives was obtained. It is indicated by the experimental results that work piece material erosion rate is increased by 3.76%, side clearance is reduced by 29.34%, surface roughness is decreased by 5.31% after a single objective optimization; the work piece material erosion is reduced by 13.95%, the side gap is decreased by 17.99%, the surface roughness is reduced 3.58% after a multi-objective optimization. |
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