Dynamic chip formation of ultrasonic-assisted micro-drilling on AISI 4340 steel

Ultrasonic vibration-assisted drilling technology has a wide range of applications in the field of precision manufacturing of difficult-to-process materials. Its principle is to combine high-frequency ultrasonic vibration with conventional drilling technology. Ultrasonic vibration-assisted drilling technology has unique advantages in reducing drilling force, improving surface quality and processing efficiency. In this paper, ultrasonic vibration-assisted drilling technology is used to process micro-holes on the surface of AISI 4340 steel. Through experiments and numerical simulation techniques, the whole process of the dynamic chip formation and the chip morphology are studied. The research results show that when the ultrasonic vibration is applied to the workpiece, the finely divided chips quickly move away from the processing area in a splashing manner. The wall defects of the micro-holes processed by the ultrasonic vibration-assisted drilling technology are suppressed and the surface roughness Ra is improved greatly.