Analysis of vibration signals to quantify displacement amplitude in the monitoring of vibration-assisted turning

Abstract

Vibration-assisted machining combines precision machining with small-amplitude tool vibration at high frequency to improve the fabrication process. It has been applied to a number of processes from turning to drilling to grinding. This work presents the validation of tool condition monitoring system based on vibration parameters. For this purpose, an experimental investigation is planned to acquire vibration signal data during the machining. This work primarily focuses on quantifying the presence of relative vibrations between the cutting tool and a workpiece during vibration-assisted turning process which helps in predicting tool life. For this purpose, an online acoustic optic emission-based vibration transducer, i.e. Laser Doppler Vibrometer, is used as a component of a novel approach. Cutting force and vibration signals were recorded and analyzed. Machine dynamic effects such as cutting force and tool wear are taken into account during the dry machining of Ti-6Al-4V alloys specimens. Identifying the correlation among tool wear, cutting forces and displacement due to vibration is a critical task in the present study. Real-time experimental findings are used to predict the evolution of displacement and tool wear in the experiment. Efficacy of a logical relationship among the process variables such as displacement, feed rate, spindle rotational speed, and depth of cut is critically examined. Results of the present study are used to establish a strategy for real-time efficient tool monitoring systems for vibration-assisted turning operation. The wear mechanisms of DNMA 432 coated carbide and uncoated carbide insert tools were examined at different combinations of feed rate, spindle speed, and depth of cut for turning of Ti-6Al-4V workpiece material.