Piezoelectric active damper for surface roughness improvement in hard turning processes

Abstract

Surface roughness and profile accuracy on rolling or sliding surfaces are critical for the wear and fatigue of a component. A high roughness or poor profile accuracy results in higher friction and higher wear rate of the surface. One of the major factors affecting the surface roughness is chatter vibrations. This paper presents a novel design and development of an active damper for chatter suppression of hard turning processes using a piezoelectric actuator and strain signal for chatter detection. The active damper consists of a piezoelectric actuator with an embedded strain gauge for measuring the vibration displacement. In this work, the radial strain signal as a result of radial chatter vibrations from the strain gauge is used as a feedback signal to the actuator using a feedback controller. A fixture was designed using special stiffeners such that it limited the tool displacements in the tangential and feed directions to only 0.2 µm and 0.4 µm, respectively, while allowing for movement in the radial direction in the actuator’s force direction. The experimental results showed a significant suppression in chatter vibrations and improvement of surface roughness using the proposed active damper. A reduction of 83% in surface roughness (Ra) was observed during the cutting process. The details of the tool design, control design, hardware implementation and system validation are given hereinafter.