Abstract: In orbiting electrical discharge machining (EDM), the orbital motion of electrode makes the cavity dimension in the work piece deviate from the design objective. Combining with the basic NC machining theory of free surface electrode, a compensation method based on generalized offset of tool path is presented. The approach uses the generalized offset technique to modify the original tool paths of electrode machining, so that the deviation of electrode orbiting can be eliminated effectively. Self-intersection problem of generalized offset is also discussed. According to the different machining objects and manners of the orbital motion, some illustrative examples are provided. The inspection results show that the machining precision is improved, and the production cycle is shortened as well.

Key words: Electrical discharge machining(EDM), Electrode orbiting, General offset