Electrophoretic deposition characteristics of an electrical discharge machined micro-tool for micro-hole polishing in quartz

This paper examines micro-hole polishing in quartz by a micro-tool coated with SiC particles by electrophoretic deposition (EPD). Quartz is a hard and brittle material, difficult to polish and fractures occur easily. Moreover, micro-hole machining by micro ultrasonic machining (MUSM) often fills the micro-hole wall with micro-chips and micro-cracks, which necessitate further polishing for better surface quality. In this paper, a micro-tool was developed for polishing micro-holes in quartz. The micro-tool was fabricated by wire electrical discharge grinding (WEDG) and had a diameter of 100 μm. A layer of SiC particles was coated onto the micro-tool by EPD. To achieve better polishing results, optimal parameters for obtaining a uniform and stable layer by EPD were first explored. After EPD, the micro-tool was employed to polish micro-holes in quartz with the help of ultrasonic vibration machining (USM). Experimental results show that polishing for a duration of 30 min at a rotational speed of 2500 rpm using 0.25 μm SiC particles at an ultrasonic amplitude of 6.3 μm can improve the surface roughness of a micro-hole wall with R _max being reduced from 0.48 μm to 0.08 μm.