Improving Productivity in an Ultrasonic-Assisted Drilling Vertical Machining Center

Ultrasonic-assisted machining, which is the application of ultrasonic vibrations to standard or “conventional” machine tools for processes such as drilling, milling, and turning, is a rapidly developing technology aimed at increasing the productivity of machining processes. While a solid foundation is being established through laboratory-based research studies, typically these processes have not yet progressed to fulfill the demanding requirements of the factory floor. The objective of the current work is to transition the ultrasonic-assisted drilling (UAD) process from the laboratory to a production system compatible with automated machining systems. This work details the design and development of an ultrasonic drilling module that has sufficient strength, stiffness, and accuracy for production demands, while maintaining powerful levels of ultrasonic vibrations that result in lowered drilling forces and faster feed rates. In addition, this work will review prior work in UAD, including the development of a module based on a vibration-isolating case using a standard tool holder. Performance of the system is shown to provide thrust force reductions, while maintaining or improving surface finish and drilling accuracy. The results from drilling several materials are presented.