Ultrasonic vibration assisted electrical discharge (UVE)

as a special composite machining technology

is one of the effective methods to improve the micro-holes machining performance of difficult-to-cut materials. In UVE micro-holes processing

according to the different forms of ultrasonic vibration

it can be divided into three modes: electrode vibration

workpiece vibration and dielectric vibration. In the UVE micro-hole processing of electrode vibration

the ultrasonic frequency is generally 20–40kHz

and the ultrasonic amplitude is about 5μm

which can improve the material removal rate by 40%–60%

and can machine the micro-hole with an aspect ratio of up to 30. In the UVE micro-hole processing of workpiece vibration

the ultrasonic frequency is mostly less than 30kHz and the ultrasonic amplitude is less than 10μm

and the material removal rate can be increased by about 40% and the micro-hole taper reduced by about 30%. In the UVE micro-hole processing of working fluid vibration

the ultrasonic frequency is generally greater than 40kHz

and the ultrasonic amplitude is greater than 5μm

which can increase the material removal rate by up to 33 times

and the hole wall roughness can reach R a 0.2μm. The research result of the three types of UVE micro-hole processing are summarized and analyzed

the three types of UVE micro-hole processing mechanisms and existing problems are discussed

and the characteristics and scope of application of the three types of UVE micro-hole processing are compared

and the development trends of UVE micro-hole processing were prospected.