Non-even wire tension in high-speed wire electricaldischarge machining

Abstract

This paper reports a study and analysis of non-even wire tension in high-speed wire electrical discharge machining (HSWEDM). This problem has been a challenge since HSWEDM was invented. The tensions of the wire electrode at both ends of a wire-winding cylinder become inconsistent when the wire electrode continues discharging for a certain period. Studies have suggested that the amount of dielectric fluid added into the discharging gap differs depending on the positive and negative moving directions of the electrode. The resistances experienced by the electrode differ because of the discharging explosion. Meanwhile, the elongations of the electrode differ according to positive and negative moving directions. Therefore, tensions are inconsistent, and non-even wire tension occurs. Factors that affect non-even wire tension are studied, and a new mode of variable wire speed reciprocating WEDM is designed. Experiments show that the machining effects in the new mode are better than those in the traditional mode under the same cutting conditions. Processing accuracy, surface quality, and cutting speed are increased. Moreover, the service life of the electrode is extended three times or more with the new mode compared with that in the traditional mode.