Research on WEDM finishing characteristics and parameter optimization of Cr12MoV material under ultrasonic water mist

Cr12MoV die steel is widely used in mold and aerospace fields due to its high hardness, high strength, and high wear resistance, often processed via wire electrical discharge machining. Currently, steam-water mist media used in near-dry wire electrical discharge machining suffer from low generation efficiency and uneven distribution, which limits the application and promotion. Research indicates that ultrasonic water mist shares similar physical properties with steam water mist while offering advantages such as high generation efficiency and uniform distribution, making it an ideal alternative medium. In this study, the effects of parameters on surface roughness and cutting speed were systematically analyzed by wire electrical discharge machining finishing in an ultrasonic water mist medium. The results show that cutting speed increases with the increase of pulse width, peak current, feed rate, and water mist concentration, and increases first and then decreases with the increase of offset, among which the feed rate has the most significant effect. Surface roughness increases with the aforementioned parameters, primarily influenced by peak current. After optimization by the multi-objective-improved gray wolf algorithm, the deviation between the predicted value and the experimental value of the model was 2.47% and 4.63%, respectively, which verifies the high accuracy of the model. Finally, compared with the steam water mist, the ultrasonic water mist medium reduces surface roughness by 4.97% and increases the cutting speed by 5.39%, indicating that the process can effectively improve the surface quality and improve the efficiency, which has important engineering application value.