Investigation of Damping Characteristics on Copper-Based Shape Memory Alloy Frictional Damper in Boring Process

Abstract

Chatter is a self-excited phenomenon in machining, especially in boring and end milling processes due to the slender nature. A passive approach of copper-based shape memory alloy frictional damping has been provided to suppress the tool chatter. Boring tools made of EN31 material have been chosen and damped with frictional dampers made of copper-based shape memory alloy such as naval brass, Muntz metal and leaded brass. Characterization study of shape memory alloys was performed using the X-ray analytical microscope, differential scanning calorimetry and impact hammer test for element confirmation, transition temperature and modal analysis, respectively. Machining performance of the proposed damping bars was investigated through logarithmic decrement, damping ratio and resonance gap of the machining system, as well as the displacement, temperature, tool wear and surface roughness in the boring process. The comparative study was reported between the damped and undamped boring bars. The comparative study revealed that better results were obtained from the boring bar damped with leaded brass. A 19.2%, 55%, 59.9% and 78.1% of reduction was witnessed in terms of temperature, displacement, surface roughness and tool wear of the boring bar damped with leaded brass compared with the unchanged boring tool holder.