关键词: 电火花铣削, 超声振动, 间隙流场, 空穴作用

Abstract:

To study the effects of ultrasonic vibration on flow field in the interelectrode gap of electro-discharge milling,a theoretical model was built based on fluid
dynamics theory where the dynamics equation in the flow field was established and the pressure equations along x and y directions were derived as well by simplifying the flow field to a two-dimensional (2D) one.These models were verified by an axisymmetric rotate 2D simulation model developed by the finite element analysis software FLUENT.The effects of alternative pressure in the flow field were analyzed and the verification experiments were carried out. Results show that the pressure of liquid along x and
y directions in the flow field changes periodically at ultrasonic frequency because of  the effects of ultrasonic vibration,which makes cavitation effect enhanced.Meanwhile the liquid flow behavior is improved substantially,the probability of short circuit and arc discharge is reduced,the machining stability and efficiency are improved,and thus the material removal rate of workpiece is enhanced.At the same time electric erosion pit depth is reduced,which in turn makes the molten metal on workpiece spread out more evenly,and finally the surface roughness of workpiece is decreased correspondingly.

Key words: electro-discharge milling, ultrasonic vibration, gap flow field, cavitation effect