Experimental Investigation on Recast Layer and Surface Roughness on Aluminum 6061 Alloy During Magnetic Field Assisted Powder Mixed Electrical Discharge Machining

AbstractThe machinability information of Zr-based bulk metallic glasses (BMGs) are recently limited but essential to provide technological recommendation for the fabrication of the medical devices due to the material’s metastable nature. This study aims to investigate the material removal rate (MRR) and surface roughness under different current and pulse-on time of newly developed Ni- and Cu-free Zr-based BMG using sinking-electrical discharge machining (EDM). By using weightloss calculation, surface roughness test and scanning electron microscopy (SEM) observation on the workpiece after machining, both MRR and surface roughness were obtained to be increased up to 0.594 mm3/min and 5.50 μm, respectively, when the higher current was applied. On the other hand, the longer pulse-on time shifted the Ra into the higher value but lower the MRR value to only 0.183 mm3/min at 150 μs. Contrary, the surface hardness value was enhanced by both higher current and pulse-on time applied during machining indicating different level of structural change after high-temperature spark exposure on the BMG surface. These phenomena are strongly related to the surface evaporation which characterize the formation of crater and recast layer in various thicknesses and morphologies as well as the crystallization under the different discharge energy and exposure time.

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Experimental Research on Discharge Forming Cutting-Electrochemical Machining of Single-Crystal Silicon

Mathematical Problems in Engineering ◽

10.1155/2021/6024662 ◽

2021 ◽

Vol 2021 ◽

pp. 1-13

Author(s):

Bin Xin ◽

Wei Liu

Keyword(s):

Surface Roughness ◽

Single Crystal ◽

Electrical Discharge ◽

Electrical Discharge Machining ◽

Electrochemical Machining ◽

Single Crystal Silicon ◽

Recast Layer ◽

Movement Speed ◽

Crystal Silicon ◽

Wedm Process

During the wire electrical discharge machining (WEDM) process, a large number of discharge pits and a recast layer are easily generated on the workpiece surface, resulting in high surface roughness. A discharge forming cutting-electrochemical machining method for fabricating single-crystal silicon is proposed in this study to solve this problem. On the same processing equipment, single-crystal silicon is first cut using the discharge forming cutting method. Second, electrochemical anodic reaction technology is used to dissolve the discharge pits and recast layer on the single-crystal silicon surface. The machining mechanism of this process, the surface elements of the processed single-crystal silicon and a comparison of the kerf width are analyzed through experiments. On this basis, the influence of the movement speed of the copper foil electrode during electrochemical anodic dissolution on the final surface roughness is qualitatively analyzed. The experimental results show that discharge forming cutting-electrochemical machining can effectively eliminate the electrical discharge pits and recast layer, which are caused by electric discharge cutting, on the surface of single-crystal silicon, thereby reducing the surface roughness of the workpiece.

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Processing Characteristics of Micro Electrical Discharge Machining for Surface Modification of TiNi Shape Memory Alloys Using a TiC Powder Dielectric

Micromachines ◽

10.3390/mi11111018 ◽

2020 ◽

Vol 11 (11) ◽

pp. 1018

Author(s):

Ziliang Zhu ◽

Dengji Guo ◽

Jiao Xu ◽

Jianjun Lin ◽

Jianguo Lei ◽

...

Keyword(s):

Surface Roughness ◽

Surface Modification ◽

Shape Memory ◽

Electrical Discharge ◽

Electrical Discharge Machining ◽

Removal Rate ◽

Recast Layer ◽

Powder Concentration ◽

Micro Electrical Discharge Machining ◽

Machining Properties

Titanium-nickel shape memory alloy (SMA) has good biomedical application value as an implant. Alloy corrosion will promote the release of toxic nickel ions and cause allergies and poisoning of cells and tissues. With this background, surface modification of TiNi SMAs using TiC-powder-assisted micro-electrical discharge machining (EDM) was proposed. This aims to explore the effect of the electrical discharge machining (EDM) parameters and TiC powder concentration on the machining properties and surface characteristics of the TiNi SMA. It was found that the material removal rate (MRR), surface roughness, and thickness of the recast layer increased with an increase in the discharge energy. TiC powder’s addition had a positive effect on increasing the electro-discharge frequency and MRR, reducing the surface roughness, and the maximum MRR and the minimum surface roughness occurred at a mixed powder concentration of 5 g/L. Moreover, the recast layer had good adhesion and high hardness due to metallurgical bonding. XRD analysis found that the machined surface contains CuO2, TiO2, and TiC phases, contributing to an increase in the surface microhardness from 258.5 to 438.7 HV, which could be beneficial for wear resistance in biomedical orthodontic applications.

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Surfactant and graphite powder–assisted electrical discharge machining of titanium alloy

Proceedings of the Institution of Mechanical Engineers Part B Journal of Engineering Manufacture ◽

10.1177/0954405415579019 ◽

2016 ◽

Vol 231 (4) ◽

pp. 641-657 ◽

Cited By ~ 21

Author(s):

Murahari Kolli ◽

Adepu Kumar

Keyword(s):

Surface Roughness ◽

Titanium Alloy ◽

Electrical Discharge ◽

Material Removal ◽

Electrical Discharge Machining ◽

Removal Rate ◽

Graphite Powder ◽

Recast Layer ◽

Dielectric Fluid ◽

Recast Layer Thickness

Surfactant and graphite powder–assisted electrical discharge machining was proposed and experiments were performed on titanium alloy in this investigation. Analysis was carried out to observe changes in dielectric fluid behaviour, material removal rate, surface roughness, recast layer thickness, surface topography and energy-dispersive X-ray spectroscopy. It was found out that the addition of surfactant to dielectric fluid (electrical discharge machining oil + graphite powder) improved the material removal rate and surface roughness. It was noticed to have reduced the recast layer thickness and agglomeration of graphite and sediment particles. Biface material migrations between the electrode and the workpiece surface were identified, and migration behaviour was powerfully inhibited by the mixing of surfactant. Surfactant added into dielectric fluid played an important role in the discharge gap, which increased the conductivity, and suspended debris particles in dielectric fluid reduced the abnormal discharge conditions of the machine and improved the overall machining efficiency.

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Experimental investigations on surface integrity issues of Inconel-690 during wire-cut electrical discharge machining process

Proceedings of the Institution of Mechanical Engineers Part B Journal of Engineering Manufacture ◽

10.1177/0954405416654092 ◽

2016 ◽

Vol 232 (4) ◽

pp. 731-741 ◽

Cited By ~ 7

Author(s):

M Sreenivasa Rao ◽

N Venkaiah

Keyword(s):

Surface Roughness ◽

Layer Thickness ◽

Process Parameters ◽

Electrical Discharge ◽

Electrical Discharge Machining ◽

Recast Layer ◽

Machining Process ◽

Micro Hardness ◽

Recast Layer Thickness ◽

Inconel 690

Nickel-based alloys are finding a wide range of applications due to their superior properties of maintaining hardness at elevated temperatures, low thermal conductivity and resistance to corrosion. These materials are used in aircraft, power-generation turbines, rocket engines, automobiles, nuclear power and chemical processing plants. Machining of such alloys is difficult using conventional processes. Wire-cut electrical discharge machining is one of the advanced machining processes, which can cut any electrically conductive material irrespective of its hardness. One of the major disadvantages of this process is formation of recast layer as it affects the properties of the machined surfaces. In this study, experimental investigation has been carried out to study the effect of wire-cut electrical discharge machining process parameters on micro-hardness, surface roughness and recast layer while machining Inconel-690 material. Interestingly, hardness of the machined surface was found to be lower than that of the bulk material. The micro-hardness and recast layer thickness are inversely related to the variation of process parameters. Recast layer thickness, surface roughness and hardness of the wire-cut electrical discharge machined surfaces of Inconel-690 are found to be in the range of 10–50 µm, 0.276–3.253 µm and 122–171 HV, respectively, for different conditions. The research findings and the data generated for the first time on hardness and recast layer thickness for Inconel-690 will be useful to the industry.

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Correlation of surface roughness and recast layer thickness in electrical discharge machining

Proceedings of the Institution of Mechanical Engineers Part E Journal of Process Mechanical Engineering ◽

10.1177/0954408915600949 ◽

2015 ◽

Vol 231 (3) ◽

pp. 414-424 ◽

Cited By ~ 4

Author(s):

Yakup Yildiz ◽

Murali M Sundaram ◽

Kamlakar P Rajurkar ◽

Ahmet Altintas

Keyword(s):

Surface Roughness ◽

Layer Thickness ◽

Electrical Discharge ◽

Electrical Discharge Machining ◽

White Layer ◽

Processing Technique ◽

Recast Layer ◽

Image Processing Technique ◽

Recast Layer Thickness ◽

Two Parameters

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 polishing method. The possible approximation of the recast layer thickness using a thermal model is also discussed.

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Surface Modification by Electrical Discharge Machining of Sintered NdFeB Magnet

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.139-141.390 ◽

2010 ◽

Vol 139-141 ◽

pp. 390-393

Author(s):

Li Li ◽

Li Ling Qi ◽

Xiao Qing Zhai ◽

Dong Wang

Keyword(s):

Surface Roughness ◽

Pulse Energy ◽

Electrical Discharge ◽

Electrical Discharge Machining ◽

Surface Characteristics ◽

Recast Layer ◽

Dielectric Fluid ◽

Machining Parameters ◽

Ndfeb Magnet ◽

Machining Parameter

In this study, the electrical discharge machining (EDM) of sintered NdFeB magnet was investigated. The surface characteristics were studied in terms of machining parameters. Correlation between the surface roughness, hardness, recast layer and the machining parameter were analyzed. Results show that an excellent machined finish can be obtained by setting the machine parameters at low pulse energy. Low pulse energy reduces the frequency of bursts of dielectric fluid and melt expulsions.

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Experimental investigation of the effects of tool initial surface roughness on the electrical discharge machining (EDM) performance

The International Journal of Advanced Manufacturing Technology ◽

10.1007/s00170-017-1399-2 ◽

2017 ◽

Vol 95 (5-8) ◽

pp. 2093-2104 ◽

Cited By ~ 9

Author(s):

Mohammadjafar Hadad ◽

Lan Quang Bui ◽

Cong Thanh Nguyen

Keyword(s):

Surface Roughness ◽

Experimental Investigation ◽

Electrical Discharge ◽

Electrical Discharge Machining ◽

Initial Surface

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Electrical discharge machining with graphene flakes in dielectric

Mechanik ◽

10.17814/mechanik.2017.3.38 ◽

2017 ◽

Vol 90 (3) ◽

pp. 186-187 ◽

Cited By ~ 1

Author(s):

Rafał Świercz

Keyword(s):

Surface Roughness ◽

Experimental Investigation ◽

Statistical Analysis ◽

Process Parameters ◽

Electrical Discharge ◽

Electrical Discharge Machining ◽

Graphene Flakes ◽

Analysis Of Results ◽

Edm Process

The article presents statistical analysis of results experimental investigation of EDM process with graphene flakes in dielectric. The relations between surface roughness and process parameters have been determined.

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