Wire EDM cutting of PCD

報告者：陳思懿指導教授 : 戴子堯 博士

Outline

• INTRODUCTION

• Influence of PCD machining

conditions

• Conclusions

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INTRODUCTION

• polycrystalline diamond is a synthetic composite cutting tool material produced by sintering together carefully selected diamond particles under conditions of high temperature and high pressure. the interstitial spaces in the diamond matrix are predominantly filled with cobalt, PCD is usually offered with a tungsten carbide (WC-Co) substrate.

• Electrical discharge machining (EDM) offers advantages over conventional techniques such as grinding and lapping in the machining of polycrystalline diamond tools in terms of process reliability and the flexibility offered by the technique for machining different shapes.

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Quality characteristics

Fig 1 PCD/carbide offset(dimensional difference ).PCD undercut and PCD/carbide notch.

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Influence of PCD grade 1/2

Fig 2 Cutting rate and surface finish as a function of pulse frequency for various PCD grades and tungsten carbide.

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Influence of PCD grade 2/2

Fig 3 SEM photographs of the cut surfaces of different PCD grades and tungsten carbide.

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Fig 4 Cutting rate and surface quality as a function of wire characteristics.

Influence of wire material

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Influence of the working Medium 1/2

Fig 5 Cutting rate and surface quality depending on the dielectric fluid.

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Influence of the working Medium 2/2

Fig 6 comparison of the surface topography of PCD samples eroded in a water bath and in an oil bath.

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Conclusions

• PCD can be machined reproducibly to a high surface quality using the wire EDM technique.

• The machining results are largely determined by the type of wire material selected and the type of dielectric fluid .

• Wires with high electrical conductivity and a low concentration of zinc on the surface are to be preferred.

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Thanks for your attention！！

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