Method and apparatus for automatic construction of electrodes for rocking-motion electric discharge machining

An apparatus for designing an electrode for electric discharge machining of a workpiece, based on a reverse shape to a shape of the workpiece by use of a CAD system, comprising:

• (a) First-reverse-solid processing means operable to obtain a first reverse solid having a reverse shape to a shape of the workpiece, from a solid of the workpiece;
• (b) Second-reverse-solid processing means operable to uniformly offset an entire surface of said first reverse solid by a thickness necessary for a discharge gap to obtain a second reverse solid;
• and
• (c) Electrode-shape processing means operable to subject said second reverse solid and one or more swept reverse solids created by copying said second reverse solid while allowing a sweep movement by a small distance in a direction conforming to a rocking motion, to a logical product (AND) operation to obtain a shape of an electrode as a third reverse solid.