Effects of axial ultrasonic vibration on grinding quality in peripheral grinding and end grinding of ULE

Axial ultrasonic vibration-assisted grinding has been widely proved to be effective on the ground quality as well as efficiency for hard and brittle materials. However, the deference of two typical modes, axial ultrasonic vibration-assisted peripheral grinding (AUPG, vibration directions are parallel to the ground surface) and axial ultrasonic vibration-assisted end grinding (AUEG, vibration directions are vertical to the ground surface), exerting on the grinding process has not yet been thoroughly investigated. In this paper, the single grain kinematic functions corresponding to AUPG and AUEG have been created to theoretically analyze the interactional mechanism of peripheral grinding and end grinding respectively. For AUPG and AUEG, their axial ultrasonic vibrations are capable of increasing the dynamic contact length, decreasing the chip thickness, but their different effects on grinding behavior need further investigation. A series of comparative experiments have been conducted subsequently, and the results show that under the identical material removal rate, axial vibration in AUPG and AUEG can decrease the grinding forces, while AUEG is with a lower one than AUPG with a factor of 39.80%. With regard to the ground surface quality and subsurface damage, AUPG shows a positive effect while AUEG shows a negative role. The grinding kinematic, grinding force, ground surface quality, and subsurface damage have been analyzed in terms of the axial ultrasonic vibration effect on the peripheral grinding and end grinding behavior theoretically and experimentally, the conclusion will be meaningful for researchers to choose the appropriate approach in applying axial ultrasonic vibration to grinding optical elements.