Simulation of Die-Sinking EDM by Discharge Location Searching Algorithm

本研究使用一种新开发的仿真算法来模拟模切电火花加工对工件几何形状的侵蚀，以忠实地模仿在间隙中发生的实际现象。该算法是一个简单的重复过程，包括：1。2.确定介质击穿强度最低的下一个放电位置；2、去除工具和工件电极；3 .分散碎片颗粒；给工具电极送料。该仿真考虑了刀具电极磨损、间隙宽度分布、刀具电极曲率和倾角以及碎屑颗粒浓度等多种影响因素，这些因素之间的相互影响非常复杂。对加工后的刀具电极和工件几何形状及间隙宽度分布的仿真结果与加工平面和方形表面的实验结果吻合较好。本研究的另一个目的是开发一种求解逆问题的仿真方法，在该方法中可以获得刀具电极形状以实现工件的最终形状。在此逆仿真中，考虑到工件和工具电极的初始形状等于其在正演仿真中的最终形状，使用了与上述正演仿真中使用的相同算法。此外，工件以与工具电极相反的方向馈送，并且分别与工具电极和工件有关的每次脉冲放电的去除体积的数据相互交换。反向仿真的结果使刀具电极和工件的形状恢复到正向仿真的初始形状。

This research deals with simulation of workpiece geometry eroded by a die-sinking EDM using a newly developed simulation algorithm for faithful imitation of the actual phenomena which are occurring in the gap. The algorithm is a simple repetition of the procedure which is comprised of : 1. determining the next discharge location where the dielectric breakdown strength is lowest, 2. removing the tool and workpiece electrodes, 3. distributing the debris particles, and 4. feeding the tool electrode. The simulation takes into account a variety of influential factors such as tool electrode wear, gap width distribution, curvature and inclination of the tool electrode, and debris particle concentration, all of which affect each other in a very complex manner. The simulation results for the geometries of the tool electrode and the workpiece after machining and for the gap width distribution agree well with the experimental results for machining of a flat and square surface.Another aim of this research is to develop a simulation method to solve the inverse problem in which the tool elctrode shape to achieve the final shape of the workpiece can be obtained. In this inverse simulation, the same algotithm as used in the forward simulation which is described above is used considering the initial shapes of the workpiece and tool electrode as equal to their final shapes in the forward simulation. Moreover, the workpiece is fed in the opposite direction toward the tool electrode, and the data concerning the removal volumes per pulse discharge pertaining to the tool electrode and workpiece, respectively, are exchanged each other. As result of the inverse simulation, the shapes of the tool electrode and workpiece were restored to the initial shapes in the forward simulation.