Research Themes

The EDM of submicron holes using ultrasmall diameter was carried out. It was possible to drill holes of approximately 0.5 µm diameter using silicon electrodes. These holes have the smallest reported diameter for holes drilled by EDM.

Paper Paper (KIT only) (Precision Engineering, Vol.34, No.1, 2010, pp.139-144)

The EDM of submicron-diameter zinc micropins was attempted using a relaxation-type pulse generator. A micropin of 0.3 µm diameter was processed, which is the smallest-diameter micropin fabricated by EDM.

Paper Paper (KIT only) (Key Engineering Materials, Vols.447-448, 2010, pp.238-241)

Chamfering and deburring by EDM were attempted using tool electrodes with the middle part thinner than the other parts. Chamfering was successfully carried out on the back sides of a microhole with a diameter of 60 µm, a deep hole with an aspect ratio of 5 and a noncircular hole.

Paper (Journal of the Japan Society of Electrical Machining Engineers, Vol.43, No.104, 2009, pp.172-178)

The possibilities for EDM at open-circuit voltages lower than 30 V are examined using a relaxation-type pulse generator. Although the material removal rate is very low, machining is possible even at an open-circuit voltage of 2 V.

Paper (International Journal of Electrical Machining, No.10, 2005, pp.21-25)

The possibility of EDM with ultralow discharge energy has been investigated using a relaxation-type pulse generator. The machining proceeded at open-circuit voltages lower than 15 V. The maximum discharge energy per pulse is as small as approximately 3 nJ under these conditions.

Paper Paper (KIT only) (Precision Engineering, Vol.30, No.4, 2006, pp.414-420)

The planetary EDM of microholes of less than 50 µm in diameter has been attempted. The planetary motion of the electrode improved the material removal rate and the volumetric wear ratio, reduces the overcut and enables the drilling of deep holes.

Paper (International Journal of Electrical Machining, No.11, 2006, pp.15-18)

The EDM of reverse-tapered microholes with a diameter of less than 100 µm and a high rate of taper. A hole 50 µm in entrance diameter and 115 µm in exit diameter was fabricated.

Paper (Proceedings of The 3rd International Conference on Leading Edge Manufacturing in 21st Century (LEM21), 2005, pp.757-760)

EDM of reverse-tapered microholes has been attempted using bent tool electrodes. Holes with a diameter of less than 100 µm and a cone angle of up to 90 degrees were successfully drilled. This technique was also used to chamfer one opening of a hole from the opposite opening.

Paper (International Journal of Electrical Machining, No.13, 2008, pp.15-20)

The bending strength of cemented tungsten carbide 10-µm-diameter micropins fabricated by micro EDM was investigated. Although the bending strength increased with a decrease in the electrical discharge energy at the finish machining of micropins, it decreased at lower discharge energy. This result was then applied for the EDM fabrication of cemented tungsten carbide ultrasmall-diameter cutting tools.

Paper (Journal of Japan Society for Abrasive Technology, Vol.56, No.6, 2012, pp.395-399)