Ultrasonic vibration–assisted polishing of cylindrical groove arrays on silicon carbide

Abstract

Thanks to its superior mechanical and physical properties, silicon carbide is a promising mold material in glass molding of micro-structured optical elements. However, the high micro-structured surface quality can be hardly generated by means of conventional abrasive polishing because of the high hardness of silicon carbide. In this article, the ultrasonic vibration was introduced to assist abrasive polishing with an aim to improve the cylindrical groove arrays’ surface quality and also to increase the polishing efficiency. First, the comparison experiments between abrasive polishing and ultrasonic vibration–assisted polishing were conducted, and then, the factors affecting ultrasonic vibration–assisted polishing performance were investigated. The experimental results indicate that through conventional abrasive polishing, the surface roughness of silicon carbide cylindrical groove arrays decreases to 25.5 nm from the precision ground surface roughness ( Ra) of 115.6 nm, while through ultrasonic vibration–assisted polishing, the surface roughness decreases to 8.6 nm with a factor of three times improvement. Furthermore, a 35-kHz vibration frequency corresponds to a smaller surface roughness than a 25-kHz vibration frequency under identical processing parameters. In the vibration amplitude range from 1.0 to 2.5 µm, the surface roughness accordingly decreases linearly, while in the range of 2.5–4.0 µm, ultrasonic vibration presents no assistance in improving the surface quality.

Removal mechanism of 4H- and 6H-SiC substrates (0001 and 0001¯) in mechanical planarization machining

“…However, SiC is difficult to machine because of its extreme hardness and chemical inertness, which limit its application considerably. 12–15…”

“…However, SiC is difficult to machine because of its extreme hardness and chemical inertness, which limit its application considerably. [12][13][14][15] The operating performance of the Si face of SiC substrates differs from that of the C face due to the crystalline anisotropy. The majority of previous studies have investigated the polishing of the Si face.…”

Surface roughness study of polyamide in nano-metric polishing using low-frequency acoustic energy

“…Their experiments were focused on the effects of the input variables (ultrasonic power, spindle speed, and feed rate) on the output responses (edge chipping size, cutting force, surface roughness, and ultrasonic power consumption). Sun et al 40 compared the abrasive and ultrasonic vibration-assisted polishing and derived the factors affecting ultrasonic vibration-assisted polishing. They observed that ultrasonic vibration-assisted polishing enhanced the surface quality three times more than the abrasive polishing process.…”