Study On Mechanism Of Low-Speed Wire Electrical Discharge Finishing In Gas

Wire Electrical Discharge Machining (WEDM) has important effect in a lot of industry stages. Nowadays the developing trends of WEDM are precise-microlization, intellectualization, individualization, environmental protection and high efficiency. WEDM in gas is a kind of newly developed technology, in which gas has been used as a dielectric. Comparing with the conventional WEDM, the new method has the features of better WEDMed surface straightness, smaller gap length, no electrochemical corrosion and no pollution in machining, so it is suitable for WEDM finishing. This paper summarized the mechanism and processing rules of WEDM, and theoretically explained the reasons for better WEDMed surface straightness with gas dielectric. Besides, the Low-Speed WEDM machine DK7632 and the 2302 surface surveying instrument were briefly introduced. The comparison experiments of finishing WEDM were conducted with mould steel Cr12MoV in water and atmosphere under the same machining parameters, and the following conclusions were obtained: 1. Under the same conditions (except the dielectric), the straightness of surfaces WEDMed in atmosphere is significantly better than that in water, and the discharge gap in atmosphere is smaller than that in water, and the surface roughness in atmosphere is nearly the same with that in water. 2. Under the same conditions (except the dielectric), the removal rate in atmosphere is lower than that in water. And the removal rate can be increased when higher winding speed is utilized. 3. With the decreasing of servo feed, the available value limits of servo voltage became smaller for both dielectrics, and the value limits in atmosphere is larger than that in water. 4. Comparing with traditional WEDM, the changing of servo voltage had less influence on evaluate parameters for WEDM in atmosphere.