Abstract
Ultrasonic machining (UM) is considered to be a very effective and relatively accurate way to engrave fine patterns and drill holes on brittle materials. This study aimed to investigate the feasibility of utilizing UM technique to fabricate parts of brittle materials in micrometers scale. Although brittle fracture (micro chipping) is the dominant material removal mechanism involved in the micro-ultrasonic machining process, poor surface roughness and deep penetrated cracks are the consequences if the machining parameters are not properly controlled. To ensure the quality of the generated surface and to improve the process efficiency, efforts have been made in this study to correlate the material removal mechanisms, surface integrity and tool wear involved in the micro-ultrasonic machining process to the machining conditions. The ultrasonic vibration frequency was kept at 20kHz and the feedrate was kept ranging from 0.1mm/min to 0.5mm/min. The effects of machining parameters such as types of abrasives, grit sizes and feedrate were investigated. It is found that by dividing the machining process into several stages, from coarse to fine, good surface integrity can be achieved without surrendering too much efficiency. Micro-components of various brittle materials such as glasses, Zerodure, fused quartz and silicon with dimension smaller than 100μm and surface roughness better than 0.15μm were successfully produced in this study.
