Study on the surface modification system with electrical discharge machine in the practical usage

Moro, Toshio

doi:10.1016/s0924-0136(04)00131-1

Cited by 3 publications

(4 citation statements)

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“…A combination of negative tool polarity, high gap voltages, short pulse on-times and long pulseoff times acts to intensify material adhesion. The high temperatures associated with sparking allow a large range of difficult to process materials to be deposited, including ceramics, and rapid quenching facilitates the production of hard coatings [1,2]. The next generation of ED machining may exploit the phenomena associated with EDC and attachment of desirable materials to neutralise and enhance the properties of the undesirable recast layer.…”

Section: Introductionmentioning

confidence: 99%

Defect-free TiC/Si multi-layer electrical discharge coatings

Murray

Cook²,

Senin

et al. 2018

Materials & Design

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The process of electrical discharge coating (EDC) may be used to deposit hard materials on conformal substrate surfaces. Next generation EDM'd components may exploit attachment phenomena to enhance recast layer properties, to avoid the need for recast layer removal. Here, a ceramic based composite layer was developed without cracking and porosity for the first time, using sequential coating using sacrificial TiC and Si electrodes. Attenuation of the discharge process by gap widening using Si debris in the gap explained improved layer properties. Composite coatings combining WC and TiC were also demonstrated, with good elemental intermixing. Attachment level was correlated strongly with melting point, with high melting point materials resisting ejection due to more rapid solidification. Nanoindentation showed the TiC and WC/TiC layers possessed the highest mean hardness

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Section: Introductionmentioning

confidence: 99%

Defect-free TiC/Si multi-layer electrical discharge coatings

Murray

Cook²,

Senin

et al. 2018

Materials & Design

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“…On the other hand, recent EDM finishing technology shows a remarkable progress, in which lower surface roughness like a mirror can be obtained by optimizing discharge conditions or by mixing metal powders into the working fluid [1][2][3][4][5][6]. Then, it is highly expected that EDM finishing will be applied as a final finishing method.…”

Section: Introductionmentioning

confidence: 99%

Improvement of Surface Characteristics for Long Life of Metal Mold by EDM in Chromium Powder Mixed Working Fluid

Wang

Kitada

Toshimitsu

et al. 2017

IJEM

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This paper aims to form a chromium carbide containing layer on metal mold steel by EDM finishing in chromium powder mixed working fluid in order to improve the surface characteristics for long life of metal mold, such as surface hardness, corrosion resistance and releasability of molded resin. The surface characteristics of carbon tool steel with low chromium content finished by EDM in chromium powder mixed working fluid were compared to those of alloy tool steel SKD11 with high chromium content. Experimental results shows that surface hardness, corrosion resistance and releasability of molded resin could be significantly improved to the same high level for both kinds of steel by EDM finishing in chromium powder mixed fluid.

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“…Generally, the tool electrodes are made up of microsized powder additives having powder material that is intended to be deposited onto the machined surface. The selected material and a binder material, both in powder form, are mixed together and sintered or partially-sintered to form powder-compacted electrodes [170][171][172][173][174][175]. Then during the PCT-EDM process, the alloying powders are released into the dielectric through the disintegration of the tool electrode by electro-thermal effects.…”

Section: Powder-compacted Tool Edm (Pct-edm)mentioning

confidence: 99%

“…As in the case of surface modification with PMD-EDM, PCT-EDM may be performed with material removal or without material removal. The combined mode of machining and material deposition by PCT-EDM is called electrical discharge alloying (EDA) by some researchers [171,172] while material deposition by PCT-EDM is called electrical discharge coating (EDC) [173,174]. With reference to In an EDA study that used copper powder with 50 µm granularity to produce electrodes at various forming pressures [176], their performance compared to a solid copper electrode currents in the range of 3 A to 16 A and pulse on time durations in the range of 50 µs to 400 µs, it was shown that the electrode wear rate was more than three times the surface deposition rate.…”

Section: Powder-compacted Tool Edm (Pct-edm)mentioning

confidence: 99%

Advancing the micro-EDM technique with powder-mixed dielectric and process modelling

Tan¹

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The electrical discharge machining (EDM) process possesses inherent characteristics that make it a promising micro-machining technique. However, micro electrical discharge machining (micro-EDM) is only used in niche applications due to the lack of an established knowledge base to facilitate process planning. The stochastic nature of material removal, sensitivity of process performance to process parameters and conditions and numerous process parameter permutations available for machining contribute to the difficulties in building a knowledge base for micro-EDM. Compounding to this complication, the process parameters and conditions in EDM and micro-EDM are distinctly different, thereby rendering limited transferability of knowledge base. Thus, focused studies on micro-EDM are needed to improve process reliability and controllability as well as to enhance process capabilities. This research has endeavoured to achieve advancement of the micro-EDM technique through a two-pronged approach of process performance enhancement and process modelling. The proposed use of powder-mixed dielectric in micro-EDM (PMD micro-EDM) is a novel initiative to adopt this established technological development in EDM (PMD-EDM) for micro-EDM. By reproducing the effects of improved machined surface quality and enhanced machined surface functional properties of PMD-EDM in PMD micro-EDM, advancements to the micro-EDM process has been achieved. The realisation of PMD micro-EDM has been achieved through employing discharge energies less than 25 µJ with sub-microsecond pulse on time durations and complemented by the use of nanopowder additives of semi-conductive and non-conductive materials in concentrations below 1 g/l. Initial investigations on the unit removal characteristics of PMD micro-EDM have shown a distinct difference in the morphology of craters produced in a powder-free and powder-mixed dielectric, thereby proving the feasibility of PMD micro-EDM. Furthermore, the observation of craters having smaller peak-to-valley heights when generated under single electrical discharge conditions has been exhibited as reductions in arithmetical mean surface roughness of 14 % to 24 % when processing with PMD micro-EDM. Improvements in machined surface quality have also been displayed through reductions in recast layer thickness of between 15 % and 35 %.

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Study on the surface modification system with electrical discharge machine in the practical usage

Cited by 3 publications

References 0 publications

Defect-free TiC/Si multi-layer electrical discharge coatings

Defect-free TiC/Si multi-layer electrical discharge coatings

Improvement of Surface Characteristics for Long Life of Metal Mold by EDM in Chromium Powder Mixed Working Fluid

Advancing the micro-EDM technique with powder-mixed dielectric and process modelling

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