Abstract
BK7 glass is an important engineering material with extensive applications in high-quality and precision transmissive optical components. However, BK7 glass is considered to be a difficult-to-cut material due to its high brittleness and nonconductivity. This article presents the use of rotary ultrasonic machining process for drilling holes in BK7 glass. No previous reports have been found in the literature to experimentally investigate the response of the BK7 glass to rotary ultrasonic drilling. The experimental investigations take into account the effect of the key rotary ultrasonic machining input parameters including the ultrasonic power, spindle speed and feed rate on the output responses of cutting force, exit chipping, surface roughness, hole cylindricity and overcut errors, and surface integrity. The results show that the input parameters within the current ranges can significantly affect the quality of the drilled holes. Moreover, the selected level of any input parameter has the ability to significantly affect the influence of the other input parameters on the output responses. Through proper selection of input parameters, holes could be drilled in BK7 glass with less fractured topography, low surface roughness (1.32 mu m), low exit chipping size (0.85), and very low cylindricity (3 mu m) and overcut (73.6 mu m) errors.