Study Of Electrical Discharge Milling In Jetted Mist

Electrical discharge milling in mist is a new EDM process that uses the gas-liquid two phase flow instead of oil based working fluid as its dielectric medium. Compared with traditional EDM, it produces less waste, and is more economical by saving the liquid recycling system and filtration system. But how to achieve a stable and high-efficiency process is the main problem to be settled presently.This paper designed a tool fixture which can hold and rotate the electrode. The rotation of the electrode can improve the gap condition by increasing the movement of the discharging point in the gap. The tool electrodes used in the experiments were made from copper pipes. The working dielectric mist was generated by MQL (Minimum Quantity Lubrication) equipment and it was transmitted to the discharge gap through the pipe electrode.Firstly, the experiments were carried out to choose the proper cutting layer depth, tool electrode wall thickness, mist pressure and tool rotation speed. Then the effects of the pulse duration, pulse interval, peak current, circuit open voltage and servo voltage on MRR(Material Remove Rate) and TWR (Tool Wear Ratio) was discussed based on the design of experiment(DOE). Then the empirical models were deducted based on the experimental data. After that, a series of comparing experiments were conducted to study the difference of the machining characteristics between EDMing of Ti-6Al-4V in oil and EDMing of Ti-6Al-4V in mist.The experimental results show that, the tool rotation can increase then machining speed by improving the machining stability. A higher rotation speed can lead to a higher MRR. The ANVOA results show that the pulse duration(Ton) is the key factor to improve the MRR, all of the machining parameters have slight influence on the TWR and the TWR remains at a relative low level. When machining Ti-6Al-4V,EDM in mist reviewed its potential advantage is achieving a higher MRR, lower Ra and nearly zero TWR.