Journal of the Korean Society of Manufacturing Process Engineers (한국기계가공학회지)

The Korean Society of Manufacturing Process Engineers (한국기계가공학회)
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A Study on the Electrical Discharge Blind Hole Tap Machining of STD11 with Copper Electrode

구리전극봉을 이용한 합금공구강재(STD11)의 비관통 방전 탭 가공에 관한 연구

  • 박인수 (한국폴리텍대학 창원캠퍼스) ;
  • 왕덕현 (경남대학교 기계공학부) ;
  • 김기태 (한국폴리텍대학 창원캠퍼스)
  • Received : 2017.03.24
  • Accepted : 2017.04.23
  • Published : 2017.06.30
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Abstract

The technology of electrical discharge tap machining may be appropriate for making thread out of highly brittle material. Especially, it is very difficult to machine tap with the traditional method if the brittle material has been hardened by quenching. In this study, the shape of electrical discharge blind hole tap machining was analyzed by discharge time, discharge current, and the flushing hole condition after quenched the tool steel of STD11 has discharged the tap shape with a screw-shaped copper(Cu) electrode. An experimental design was planned and analyzed by Taguchi robust experimental design. The result showed that the shape of the blind hole discharge tap was influenced by the flushing hole, discharge time, and discharge current. The most important factor of the processing conditions was found to be the discharge current. When blind hole EDM with a copper electrode with a flushing hole was conducted, the discharged shape was found to be smooth and the angle of the discharged tapped thread was also found to be close to the thread angle of $60^{\circ}$. As the values of discharge time and discharge current increased, the EDMed surface coarsened due to the increase of the single discharge energy and the shape of the thread collapsing.

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References

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  1. Electron Discharge Machining (EDM) and Hole EDM of Cold Heat-treated Tool Steel Molds (STD11) by using Cu Electrodes vol.17, pp.4, 2018, https://doi.org/10.14775/ksmpe.2018.17.4.076