| dc.description.abstract | This study aimed to observe of gap phenomena and develop the electrochemical discharge machining method for sapphire. It was found that the thickness of the gas film, the discharge spark, and the droplet sliding frequency in the electrochemical discharge affected the processing quality and efficiency. This study used a high-speed camera to photograph and observe the bubble formation, gas film coating, and the phenomenon between tool electrode and workpiece during electrochemical discharge processes. The formation mechanism and processing characteristics of the gas film were understood through experiments.
Furthermore, this study executed the sapphire electrochemical discharge machining parameter experiment and observed the electrode gap phenomenon during electrochemical discharge processes. The machining parameters include the liquid level, working voltage, electrode rotational speed, and duty factor. They analyzed and discussed the effect of each machining parameter on the gas film thickness, current value, electrode consumption, and droplet slip frequency. Moreover, this study aimed to obtain optimized processing parameters to overcome the difficulty of processing sapphire.
The results show that a high-speed camera could effectively capture the bubble formation and gas film coating situation during electrochemical discharge processes. In addition, a higher bubble incorporation rate can increase the machining capability and reduce the side discharge phenomenon. Therefore, this study could obtain better processing hole depth through observation and analysis to improve gas film stability and machining capability. Moreover, at liquid level of 700 µm, working voltage of 48 V, duty factor of 50 %, and tool electrode rotational speed of 200 rpm, better average hole depth of 86.7 μm and pore diameter of 129.5 μm could be obtained.
Keywords: electrochemical discharge machining; gas film; electrode gap; sapphire | en_US |