Simulation of Wire EDM (3rd Report)

In the present study, the accuracy of the finish cut for Wire EDM is analytically and experimentally investigated. In order to simulate the finish cut, the explosive force, electrostatic force and electromagnetic force are estimated based on the wire deflection. The simulated wire deflection on the finish cut is compared to the measured value. Problems associated with the finish cut that were revealed by the simulated results are described. The effect of electrostatic force on the cut wall straightness and countermeasures to prevent this effect on the finish cut are described. The results of the present study are as follows; 1) the explosive force of the finish cut decreased to 30-60% of the rough cut, depending on the skimmed depth, 2) the dielectric constant of the water in the gap decreases to 20-30% of the nominal value during the finish cutting, 3) the electrostatic force may cause irregular wire movement, and for thick work pieces may overcut at the corners, 4) the electrostatic force results in concave cut walls, and 5) the finish cutting in air is useful for decreasing the electrostatic force and obtaining good wall straightness.