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Journal ArticleDOI

Effect of micro double helical grooved tools on performance of electric discharge drilling of Ti-6Al-4V:

20 Feb 2021-Vol. 235, Iss: 11, pp 1832-1847
TL;DR: In this article, the authors proposed a method to mine high aspect ratio holes on Ti-6Al-4V superalloys, which is a topic of both industrial and academic interest.
Abstract: Machining of complex features and holes on superalloys is a topic of both industrial and academic interest. Though the demand for high aspect ratio holes on Ti-6Al-4V is high in aerospace, biomedic...
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Journal ArticleDOI
TL;DR: In this article , the authors proposed the use of a slotted tool with different cross-sections and calculated the dielectric flow field, debris trajectory, and cooling rate using computational fluid dynamics (CFD).
Abstract: In micro-electrical discharge milling (μED-milling), the rotation and forward feed motion of the tool is the key element responsible for evacuation of the debris particles. The inability to eliminate debris from the interelectrode gap (IEG) causes secondary discharge, short-circuit, and hampers removal rate. This problem is predominant in electrical discharge machining (EDM) where the tool is stationary. Various methods have been devised in the literature to boost debris removal from the IEG. In this paper, the use of a slotted tool with different cross-sections is proposed. The dielectric flow-field, debris trajectory, and cooling rate are calculated using computational fluid dynamics (CFD). Effect of different parameters such as tool rotation, gap size, jet velocity, the shape of slots on the dielectric flow is determined. The slots on the tool create turbulence which enhances the debris removal from the IEG. It also provides the space to accumulate the debris particles, thereby increasing the removal rate. The variation in the dielectric flow-field greatly affects the debris flushing from the IEG. The trajectory of the debris particles depends on their initial position in the IEG and they cool rapidly, which is validated using simulation and mathematical approach.

1 citations

Journal ArticleDOI
TL;DR: In this article , the three-step drill has changed the main cutting-edge structure, which is more conducive to chip breakage, and the results show that the improved drill has good chip breaking performance, low thrust force, and better machining performance compared with the twist drill.
Abstract: As the research progresses, titanium alloy materials have more applications in aerospace and other fields. However, problems such as chip winding and serious tool wear are easy to occur in the machining process. In this research, the three-step drill has changed the main cutting-edge structure, which is more conducive to chip breakage. Firstly, the drilling force of the three-step drill bit is analyzed, and the alternating stress that makes the chip thickness change is obtained by the cutting-edge structure of the three-step drill bit. The simulation and experiment are verified by each other, and the feasibility of three-step drilling to improve the processing quality is obtained. The results show that the improved drill has good chip breaking performance, low thrust force, and better machining performance compared with the twist drill. In addition, the improved drill can obtain a more complete inner wall of the hole and reasonably improve the surface quality. Through experiments, it is found that changing cutting parameters such as feed rate has different effects on chip thickness, thrust and tool wear. It was found that the drilling force was reduced by drilling Ti6Al4V material with the three-step drill. Moreover, the three-step drill can produce smaller chip thicknesses and make the chip more prone to breakage when compared with the twist drill. The high wear of three-step drill bits can also be better weakened by coating materials.
References
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Journal ArticleDOI
01 Nov 2008
TL;DR: In this paper, the authors present an extensive experimental analysis of the micro-EDM process to explore the relationship between accuracy as a function of depth of micro-holes drilled using micro-electric discharge machining.
Abstract: Micro-electric discharge machining (micro-EDM) has evolved as one of the prominent processes to generate high-aspect-ratio and accurate micro-structures in many industrial applications. This paper presents an extensive experimental analysis of the micro-EDM process to explore the relationship between accuracy as a function of depth of micro-holes drilled using micro-EDM drilling. It is shown that a depth of 5.0 mm can be achieved by a 200 μm diameter tool electrode while controlling the regular process parameters, but beyond this length, the process is governed by a number of derived phenomena such as secondary sparking, debris accumulation, etc. instead of the regular processing parameters. The optimum depth of the hole that could be achieved with a good accuracy i.e. a minimum oversize lies between 2.5 and 5.0 mm, the largest depth that could be achieved was 8.33 mm. The highest aspect ratio achieved in this experiment was 15.63.

31 citations


"Effect of micro double helical groo..." refers methods in this paper

  • ...5 and 5mm.(5) Using image processing techniques the thickness of the recast layer can be quantified and used to establish a correlation coefficient to map the thickness of recast layer from the data of surface roughness....

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Journal ArticleDOI
13 May 2019
TL;DR: Hybrid electric discharge machining (EDM) has been a promising technique for improving overall machining efficiency for hard-to-cut material as mentioned in this paper, which has been related to the c...
Abstract: Hybrid electric discharge machining (EDM) has been a promising technique for improving overall machining efficiency for hard-to-cut material. This, to some extent, has been related to the c...

17 citations


"Effect of micro double helical groo..." refers background in this paper

  • ...However, its high toughness and decreased thermal conductivity make it one of the most difficult to machine materials.(1) The ever-increasing demand for miniaturization is prompting the research community to develop methods to drill miniaturized holes with good quality....

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Journal ArticleDOI
01 Jun 2017
TL;DR: In this article, a correlation between recast layer thickness and surface roughness data obtained from an experimental study was analyzed and a correlation correlation between these two parameters has been established and the correlation has the potential to predict the recast-layer thickness on spark-eroded surfaces from simple roughness values instead of using the prevailing timeconsuming and tedious etching and polish.
Abstract: Electrical discharge machining (EDM) is an extensively used method in the machining of electrically conductive materials. Recast or white layer formation is undesirable, but inevitable, result of EDM and needs to be understood and accurately determined to efficiently perform post-treatment processes for removing the recast layer caused by EDM process. In this study, recast layer thickness and surface roughness data obtained from experimental study were analyzed and a correlation between these two parameters has been established. Image-processing technique has been used for obtaining of recast layer thickness data. It was observed that the correlation between recast layer thickness and surface roughness increases remarkably with the increase of working current and pulse time. The correlation obtained in this study has the potential to predict the recast layer thickness on spark-eroded surfaces from simple surface roughness values instead of using the prevailing time-consuming and tedious etching and polish...

16 citations


"Effect of micro double helical groo..." refers methods in this paper

  • ...Using image processing techniques the thickness of the recast layer can be quantified and used to establish a correlation coefficient to map the thickness of recast layer from the data of surface roughness.(6) One of the major challenges in EDM is debris removal....

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Journal ArticleDOI
Yao Sun1, Yadong Gong1, Xuelong Wen1, Guoqiang Yin1, F.T. Meng1 
TL;DR: In this paper, a low speed wire electrical discharge machining (LS-WEDM) is presented to prepare solid helical micro end milling with helical blades, which can realize visual predictability and provide theoretical basis for parameters selection.

16 citations


"Effect of micro double helical groo..." refers background in this paper

  • ...10mm.(14) To understand the debris transportation many researchers have modeled the fluid flow of the dielectric in the inter-electrode gap....

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Journal ArticleDOI
TL;DR: In this paper, a setup for high speed imaging in micro meter scale of a common EDM drilling process using electrode with multi-hole flushing is described, and the analysis of the erosion process is performed within two conditions: first, the initial contact of the electrode with the material surface and second, erosion inside a predrilled hole.

15 citations


"Effect of micro double helical groo..." refers methods in this paper

  • ...An observation of flushing behavior by particle velocimetry tracking and its confirmation by computational fluid dynamics (CFD) simulation showed that the prime factor affecting the debris trajectory was the outflow of dielectric from the electrode.(8) Modification of the EDM drilling tool is also an upcoming area for enhancing the debris removal from the machining zone with Wire Electric Discharge Turning (WEDT) being one of the prominent manufacturing methods to develop such tools....

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