Experimental investigation of brittle material removal fraction on an optical glass surface during ultrasound-assisted grinding

摘要

Ultrasound-assisted grinding (UAG) is generally considered as one of the most efficient and cost-effective techniques to machine optical glass. To understand the influence of the UAG parameters on the surface quality of optical glass, a series of experiments was conducted on a precision grinder machine assisted with an axial ultrasonic vibration device. On the basis of the mechanism of removal of hard, brittle materials, we propose a new surface-quality parameter for optical glass subjected to UAG: the brittle material removal fraction (BRF), which is related to the area fraction of brittle material removed from a machined surface. To calculate the BRF, an image-processing algorithm was developed by analyzing microtopographic images of the machined optical glass surface. The BRF was determined for different machining parameters (cutting depth, wheel speed, feed rate, and ultrasonic vibration amplitude) and was found to be dependent on the surface roughness. The grinding force measured in the UAG experiments exhibited a similar trend to the BRF with respect to the different machining parameters. Therefore, the BRF is a reasonable variable for estimating the surface quality of optical glass subjected to UAG.