Transactions of the Korean Society of Machine Tool Engineers (한국공작기계학회논문집)

The Korean Society of Manufacturing Technology Engineers (한국생산제조학회)
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Machining Characteristics of WEDM due to Electrical Conductivity of Dielectric

방전액의 전도율의 변화에 따른 와이어방전가공의 가공특성

  • 김창호 (동의대학교 대학원 기계공학과) ;
  • 강재원 (동의대학교 기계공학과)
  • Published : 2006.12.15
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Abstract

This work deals with the electrical conductivity of dielectric on output parameters such as metal removal rate and surface roughness value of a carbon steel(SM25C) and sintered carbides cut by wire electrical discharge machining (WEDM). Dielectric has several functions like insulation, ionization, cooling, the removal of waste metal particles. The presence of minute metal particles(debris) in spark gap contaminates and lowers the breakdown strength of dielectric. And it is considered that too much debris in spark gap is generally believed to be the cause of arcing. Experimental results show that increases of cobalt amount in carbides affects the metal removal rate and worsens the surface quality as a greater quantity of solidified metal deposits on the eroded surface. Lower electrical conductivity of the dielectric results in a lower metal removal rate because the gap between wire electrode and workpiece reduced. Especially, the surface characteristics of rough-cut workpiece and wire electrode were analyzed too. Debris were analyzed also through scanning electron microscopy(SEM) and surface roughness tester. Micro cracks and some of electrode material are found on the workpiece surface by energy dispersive spectrometer(EDS).

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References

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