Procedure in developing a longitudinal-torsional vibration-assisted micro-milling system

Abstract

Micromachining is an advanced microfabrication technique for micro-sized or micro-accuracy products through subtractive manufacturing such as micro-milling. Vibration-assisted machining (VAM) is a method in which small amplitude vibrations are applied to the tool or workpiece to enhance the fabrication process. Milling results could be improved by adding longitudinal and torsional vibration to the tool using piezoelectric components vibrating at the ultrasonic frequency with an amplitude of less than 1 μm is used. A slip ring is required to transmit electric power from a static structure to a rotating frame. After the power has been transmitted to the system, an ultrasonic horn, called an acoustic horn or sonotrode, amplifies the vibrations at the tool’s tip. Since the excitation vibration is only longitudinal, the magnification of the vibration at the tooltip is also only longitudinal. Grooves are added to the side of the ultrasonic horn to produce torsional vibrations. This vibration is then simulated through finite element analysis software, explicitly using explicit dynamics. A 3D simulation is run for a quarter cycle of micro-milling through a Ti-6Al-4V material. It could be concluded that the LTVAM application may improve machining quality, such as temperature reduction of up to 9%, cutting force reduction of up to 35%, and surface roughness improvement of up to 27%.