Investigation on ultrasonic elliptical vibration boring of deep holes with large depth–diameter ratio for high-strength steel 18Cr2Ni4WA

An ultrasonic elliptical vibration boring device for deep hole parts was designed, and the modal analysis, harmonic analysis, and transient analysis of this device were analyzed using finite element method. The results of harmonic analysis proved the feasibility of the design scheme, and transient analysis results indicated that the design scheme could realize elliptical vibration of the tool tip. The structure parameters of this device were optimized based on finite element analysis. Impedance measurement results of the device indicated that the ultrasonic elliptical vibration boring device was reliable. Ultrasonic elliptical vibration boring experiments of deep hole parts for high-strength steel 18Cr2Ni4WA were performed on a high-precision machine tool. The experimental results indicated that increasing the excitation voltage could effectively reduce the cutting force and surface roughness, and improve the stability of the boring process. Decreasing the rotation speed, feed speed, and cutting depth could effectively reduce the cutting force and surface roughness, and improve the stability of the boring process. Compared with traditional boring, ultrasonic elliptical vibration boring can significantly reduce the boring force, surface roughness, cutting chip length, and vibration of the boring bar. This work is of great significance for achieving high-efficiency and precision machining of deep hole parts.