Study on Surface Quality of BK7 Optical Glass by Longitudinal Torsional Composite Ultrasonic Vibration Milling

Abstract

BK7 optical glass has been widely used in modern high-tech fields such as aerospace, automotive, optical precision instruments, electronic information, etc. due to its excellent performance, but its gap between plasticity and hardness is huge, making traditional machining easy to appear sub-surface. Damage and other phenomena, surface quality is difficult to meet the requirements. In this paper, the ultrasonic milling dynamics model was firstly established, and then the multi-factor method was used to detect the longitudinal torsional composite ultrasonic milling and ordinary milling of BK7 optical glass, and the surface roughness and surface topography of different spindle speed, milling speed and milling depth were analyzed. Finally, the laws and mechanisms affecting the quality of the machined surface were obtained. It is found that the surface quality is best when the spindle speed is 3000r/min and the milling depth is 0.2mm; the surface quality of BK7 optical glass decreases with the increase of milling speed. The surface quality and processing efficiency of BK7 optical glass are improved by longitudinal torsional composite ultrasonic vibration milling, and the optimal process parameters for BK7 optical glass longitudinal torsional ultrasonic milling are provided.