Reverse simulation of sinking EDM applicable to large curvatures

This paper describes the development of a reverse simulation method for sinking electrical discharge machining (EDM) which can obtain tool electrode shapes with which desired workpiece shapes can be machined precisely taking into consideration tool electrode wear. In the reverse simulation method developed, the tool electrode is machined using a workpiece with the same initial shape as the target workpiece shape, applying the discharge location search algorithm developed for forward simulation. The data on the removal volumes of the tool electrode and workpiece per pulse, obtained from experiments, was switched in reverse simulation. To compensate for error due to curvature, the removal volumes of the tool electrode and workpiece were divided and multiplied by the ratio of the workpiece area facing a unit area of the tool electrode, respectively. Experimental results showed that the workpiece shape after actual machining using the tool electrode obtained from reverse simulation was closer to the target workpiece shape than when the tool electrode shape was obtained by offsetting the target workpiece shape at a distance equal to the gap width.

► Reverse simulation method for sinking electrical discharge machining was developed.
► The tool electrode shape to machine the target workpiece shape can be obtained.
► Influences of tool electrode wear and curvature were taken into consideration.