Effect of ultrasonic vibration on the performance of deep hole drilling process

Abstract

Deep hole drilling process is extensively used in demanding applications, namely plastic injection moulding, oil and gas industry and automobile engines. This drilling process encounters problems such as improper chip evacuation, poor surface finish, roundness variation, and high tool wear, which affects the hole quality. To overcome these limitations, ultrasonic vibration-assisted deep hole drilling (UVADD) is performed in this work. The high-frequency vibrations were imparted into the ASTM A36 steel (workpiece) to induce reciprocating motion, which is mounted over a transducer. A special fixture arrangement was fabricated to hold the transducer in the drill bed. This helps to transfer the vibration to the workpiece. The machining performance of UVADD was analyzed by means of cutting force, tool wear, torque, hole quality, surface roughness, machining time and chip morphology, and the performances were also compared with the conventional deep hole drilling (CDD) process. Results suggested that a reduction in cutting force and torque was observed for UVADD. This is due to small discontinuous chips generated. Hole quality showed a drastic decrease in burr formation and surface roughness along with a uniform radius around the periphery. From the tool wear examination, it was also evident that no built-up edge formation occurred along the cutting edge owing to effective penetration of coolant and reduction in cutting temperature. This comprehensive analysis revealed that UVADD provided an enhancement in machining performance as compared to CDD.