Abstract
A new method using a polishing slurry together with ultrasonic longitudinal and torsional vibrations from a source with a diagonal slit vibration converter is developed for the hole machining of brittle materials. We predict that removal rate and machining accuracy will be improved using ultrasonic longitudinal–torsional vibration when compared with using conventional longitudinal vibration machining. In experiments, soda-lime glass is used as the processing material, and hole roundness error and machining time are measured to assess the hole machining characteristics. We find that machining accuracy is improved using ultrasonic longitudinal–torsional vibration.