| Summary: | 碩士 === 正修科技大學 === 機電工程研究所 === 98 === In this study, according to electrical discharge machining method, and a mechatronical dynamic electrical EDC tester with the discharge supply electricity instrument, and the electrode covered with insulating sleeve, and way to change the cover sleeve, supply voltage, discharge time and gap distance is employed to investigate the effects of different process parameters on the surface mechanical and tribological properties of coating layer.
The experimental results, at the supply voltage 100V, 200V and 300V, the coating layer of covered sleeve of the coating thickness and hardness increases with increasing time, but decreases with increasing machining time after 142s. However, the coating thickness and hardness increases with increasing supply voltage at the same machining time, but decreases with increasing supply voltage after 200V. Furthermore, on the conditions of the supply voltage 200V, gap distance 100贡m and different machining time, the coating thickness, hardness and distribution of the covered and without covered sleeve increases with increasing time, but decreases with increasing machining time after 142 seconds. The coating thickness and hardness of covered sleeve were 17贡m and 1453Hv, that the coating thickness and hardness of without covered sleeve were 14.65贡m and 1020 Hv, and covered than without covered more 16% of the thickness and 42% of the hardness.
Correlation formula for coating thickness in terms of the coating method of covered sleeve will be different with the supply voltage, machining time and gap distance is obtained according to Least-squares method regression analysis. Correlation formula for coating hardness in terms of the coating method of covered sleeve with the machining time for 142s, gap distance for 100贡m and different supply voltage to predict the coating hardness of different parameters.
At the gap distance for 100贡m, machining time for 142s and different supply voltage, the friction coefficient of coating layer was found in the range of 0.2~0.3. The wear rate of coating layer at the supply voltage for 200V was the lowest, the supply voltage for 100V was the highest.
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