Transient separation cutting characteristic of axial ultrasonic vibration–assisted cutting

Abstract

Axial ultrasonic vibration–assisted cutting has been proposed and proved preponderance on cutting performance; however, the transient separation cutting characteristic has not been clearly revealed. This paper focuses on the transient separation cutting characteristic of axial ultrasonic vibration–assisted cutting and its influence on the cutting performance. First, the separation cutting criteria, including feed coefficient and phase shift, are established and influence factors, such as feed rate, amplitude, and phase shift, are systematically analyzed. Subsequently, the duty ratio is deduced and calculated, and some features and a control mechanism are introduced. In addition, a transient separation cutting model with four stages is demonstrated. The reason for the average cutting force reduction by the transient separation cutting characteristic is also stated. Finally, the verification of the separation cutting and transient separation cutting model and the comparison of the feed thrust force and parameter influences on the cutting performance are experimentally performed. The transient signals of different duty ratios 0.55 to 1 are obtained, and 10 to 40% reductions of feed thrust are measured both by a PCB sensor and a Kistler dynamometer. The influence degree of the feed coefficient, spindle rotation speed, and cutting depth on the performance is analyzed. A parameter combination of smaller feed coefficient, moderate spindle rotation speed, and smaller cutting depth is suggested to obtain a better cutting performance by fully considering the cutting force, surface roughness, and tool life.