| dc.description.abstract | The main purpose of this study is to develop innovative continuous flow wire electrochemical discharge machining (WECDM) and wire electrophoretic deposition polishing methods for quartz wafer materials. This thesis is divided into two major parts. The first part focuses on the research of ultrasonic vibration assisted wire electrochemical discharge machining with continuous electrolyte flow. When processing quartz wafers, a micro area with a dense insulating gas film structure can be formed between the wire electrode and the quartz workpiece to create a micro area for WECDM. Unstable discharge phenomena and excessive heat generation can be significantly reduced by using pulse power sources and ultrasonic-assisted processing, which prevents wire electrode breakage and extensive electrode wear. Furthermore, it can also improve processing accuracy and cutting speed to overcome the challenges of processing quartz wafer materials. This study employs a KOH electrolyte for parameter experiments to investigate the impact of processing parameters, such as working voltage, duration time, duty factor, feed rate and ultrasonic power on processing quality characteristics. These quality characteristics include average slot width and surface morphology. Experimental results indicate that under the influence of pulse power and ultrasonic vibration, with the following combination of processing parameters: working voltage of 44V, duration time of 100µs, duty factor of 40%, feed rate of 5µm/s, and ultrasonic power of 2 level, a smaller slot width of 0.208mm can be achieved after WECDM.
The second part involves the study of ultrasonic-assisted electrophoretic deposition for polishing the sidewalls of quartz wafers. After ultrasonic-assisted WECDM with continuous electrolyte flow, the sidewall polishing of the slots is performed by a coated electrode using electrophoretic deposition in a confined area. In this experiments, the mechanism of the original WECDM machine was used. After slicing the slot with WECDM, the fixture was replaced to perform electrophoretic deposition and polishing on the slot sidewalls. Zinc-coated brass wire was used as the tool electrode, and a cylindrical brass structure was used as the auxiliary electrode. Electrophoretic deposition was performed using a NaOH electrolyte containing silicon carbide (SiC) particles. The quartz sidewalls after cutting were polished by rotating the winding mechanism to feed the wire electrode. The study investigates the effects of processing parameters, such as working voltage, SiC particle concentration, feed rate, polishing times and ultrasonic power level on the quality characteristics of polished sidewalls in quartz wafers. The quality characteristics include surface roughness and surface morphology. Experimental results show that the lowest surface roughness value of 0.112μmRa was achieved in this study when process with a working voltage of 12V, a SiC particle concentration of 13wt.%, a feed rate of 10μm/s, 4 polishing times, and ultrasonic power level of 2-stage. The surface roughness improvement rate was 87.2%. | en_US |