Development of Fabrication Method of Holes inside a Hole by Means of Electrical Discharge Machining

--- Feasibility of Reduction of Machinable Hole Inner Diameter ---

Abstract

Removal machining cannot generally fabricate a hole on the inside wall of another hole. In other words, removal machining has the limitation for its fabricatable hole shape. To overcome the limitation, our research group has developed the devices which can fabricate such holes. The devices developed in the previous studies could machine a hole of 3.1 mm in inner diameter inside another hole of 21 mm in inner diameter, and could expand the inner diameter of the hole to 15.4 mm. However, the hole with inner diameter less than 3.1 mm cannot be machined. Therefore, this study has developed a new device which can machine such holes with small inner diameter. The basic experiment proves that the new device has the ability to machine the holes.