The Effects of Pulse on Time and Arc on Time on Surface Quality in Wire-EDM of ASSAB XW-42 and ASSAB 8407 2M Tool Steels

2016 ◽  
Vol 836 ◽  
pp. 173-178 ◽  
Author(s):  
Hasriadi ◽  
Bobby Oedy Pramoedyo Soepangkat ◽  
H. Subiyanto
Keyword(s):  
Surface Quality ◽  
Electrical Discharge Machining ◽  
Crack Density ◽  
Recast Layer ◽  
Work Piece ◽  
Tool Steels ◽  
Recast Layer Thickness ◽  
Pulse On Time ◽  
Wedm Process

In this study, the effects of cutting parameter on surface quality was investigated experimentally in wire electrical discharge machining (WEDM) process of ASSAB XW-42 and ASSAB 8407 2M tool steels. The surface quality of WEDMachined (WEDMed) was usually characterized by its roughness, recast layer and cracks. The experiments were conducted under different setting of pulse on time and arc on time on. It can be concluded that surface roughness, recast layer thickness and density of microcracks increased proportionally with pulse on time and arc on time. Thin recast layer and low crack density in the surface of ASSAB XW-42 tool steel was due to the low thermal conductivity of work piece material.

Performance analysis of Cu-W-B4C composite tool during electrical discharge machining of titanium alloy

2020 ◽  
pp. 095440622095159
Author(s):  
Anshuman Kumar Sahu ◽  
Siba Sankar Mahapatra
Keyword(s):  
Titanium Alloy ◽  
Boron Carbide ◽  
Electrical Discharge ◽  
Electrical Discharge Machining ◽  
Crack Density ◽  
Tool Material ◽  
Work Piece ◽  
Machining Parameters ◽  
Weight Percentage ◽  
Pulse On Time

Electrical discharge machining (EDM) is broadly used in machining of parts having intricate shapes made of difficult-to-machine materials. During EDM, tool fabrication time through conventional machining processes is generally excessively high. Therefore, alternate tool material and fabrication strategy is sought to reduce machining lead time. In this work, composite tools made of copper, tungsten and boron carbide have been prepared through powder metallurgy (PM) route. The performance of these tools is studied during machining of titanium alloy work piece. The input parameter considered are tool material parameters such as weight percentage of tungsten and boron carbide in the tool and machining parameters like peak current, pulse-on-time and duty cycle. The performance of these tools are evaluated considering the performance measures such as material removal rate (MRR), tool wear rate (TWR), average surface roughness (Ra), surface crack density (SCD), white layer thickness (WLT) and micro-hardness (MH). It is observed that the tool materials have been transferred onto the machined surface forming a hard layer with increased weight percentage of oxygen and carbon during machining. The PM tools exhibit similar performance as solid copper tool with respect to MRR, TWR and surface integrity.

Optimization and surface modification in electrical discharge machining of AA 6061/SiCp composite using Cu–W electrode

2015 ◽  
Vol 231 (3) ◽  
pp. 332-348 ◽  
Author(s):  
Balbir Singh ◽  
Jatinder Kumar ◽  
Sudhir Kumar
Keyword(s):  
Process Parameters ◽  
Electrical Discharge Machining ◽  
Removal Rate ◽  
Surface Characteristics ◽  
Electrode Wear ◽  
Material Transfer ◽  
Machined Surface ◽  
Recast Layer Thickness ◽  
Pulse On Time ◽  
Pulse Off Time

This paper presents the experimental investigation on the electro-discharge machining of aluminum alloy 6061 reinforced with SiC particles using sintered Cu–W electrode. Experiments have been designed as per central composite rotatable design, using response surface methodology. Machining characteristics such as material removal rate (MRR), electrode wear ratio (EWR), and surface roughness (SR) have been investigated under the influence of four electrical process parameters; namely peak current, pulse on time, pulse off time, and gap voltage. The process parameters have been optimized to obtain optimal combination of MRR, EWR, and SR. Further, the influence of sintered Cu–W electrode on surface characteristics has been analyzed with scanning electron microscopy, energy dispersive spectroscopy, and Vicker microhardness tests. The results revealed that all the process parameters significantly affect MRR, EWR, and SR. The machined surface properties are modified as a result of material transfer from the electrode. The recast layer thickness is increased at higher setting of electrical parameters. The hardness across the machined surface is also increased by the use of sintered Cu–W electrode.

scholarly journals The Effect of Discharge Current and Pulse-On Time on Biocompatible Zr-based BMG Sinking-EDM

2020 ◽  
Vol 10 (1) ◽  
pp. 401-407
Author(s):  
Yanuar Rohmat Aji Pradana ◽  
Aldi Ferara ◽  
Aminnudin Aminnudin ◽  
Wahono Wahono ◽  
Jason Shian-Ching Jang
Keyword(s):  
Surface Roughness ◽  
Metallic Glasses ◽  
Electrical Discharge ◽  
Material Removal ◽  
Electrical Discharge Machining ◽  
Removal Rate ◽  
Surface Hardness ◽  
Recast Layer ◽  
Surface Evaporation ◽  
Pulse On Time

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.

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

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.

Analysis of Dimensional Accuracy (Over Cut) and Surface Quality (Roughness) in Electrical Discharge Machining of Inconel-718 Alloy

2019 ◽  
Vol 969 ◽  
pp. 644-649
Author(s):  
Rakesh Kumar ◽  
Anand Pandey ◽  
Pooja Sharma
Keyword(s):  
Inconel 718 ◽  
Electrical Discharge ◽  
Electrical Discharge Machining ◽  
Dimensional Accuracy ◽  
Work Piece ◽  
Tool Electrode ◽  
Affecting Factors ◽  
Inconel 718 Alloy ◽  
Electrical Discharge Drilling ◽  
Pulse On Time

Inconel-718 is a nickel based super alloy (difficult-to-cut material) used in aerospace industry. Analysis of machining performances viz. Over Cut (OC) & Surface Roughness (SR) for Inconel-718 through rotary Cu-pin tool electrode have been carried out. Peak current (Ip), pulse-on time (Ton), tool rotation (Nt) & hole depth (h) were used as input factors in Electrical Discharge Drilling (EDD) of Inconel-718 work-piece. Effect of input parameters on performance characteristics like OC & SR were found by Taguchi’s L9 (34) orthogonal array. It is reveals that Ip & h are most affecting factors that affects OC & SR. The Scanning Electron Microscope image was used to measure diameter of hole on work-piece after machining.

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

2016 ◽  
Vol 231 (4) ◽  
pp. 641-657 ◽  
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.

Modeling of Recast Layer in Micro-Electrical Discharge Machining

2010 ◽  
Vol 132 (3) ◽  
Author(s):  
P. C. Tan ◽  
S. H. Yeo
Keyword(s):  
Numerical Model ◽  
Electrical Discharge ◽  
Prediction Models ◽  
Electrical Discharge Machining ◽  
Performance Measure ◽  
Recast Layer ◽  
Micro Edm ◽  
Machined Surface ◽  
Functional Layer ◽  
Pulse On Time

The thickness of recast layers produced during electrical discharge machining (EDM) is an important process performance measure as it may indicate an extent of crack propagation in a machined surface or thickness of a functional layer alloyed onto a machined surface. Thus, the availability of the recast layer thickness prediction models is needed to allow better control of machining outcomes, which becomes more vital for micro-EDM due to the microscale of machined features. The proposed numerical model, based on a multiple discharge approach for recast layer prediction, is developed to fill an existing gap in micro-EDM. The multiple discharge approach accounts for the overlapping nature by which craters are generated on the machined surface and considers the recast layer to be a combination of individual recast regions from individual craters. The numerical analysis, based on finite element methods, is used to determine the melting isotherms due to heat inputs on overlapping crater profiles. Then, a hemispherical-capped crater profile is estimated by applying a recast plasma flushing efficiency to the amount of molten material bounded by the melting isotherm. Finally, the recast region is defined to be bounded by the melting isotherm and crater profile. The model, developed for a peak discharge current of 1.45 A and pulse on time between 166 ns and 606 ns, predicted recast layer thicknesses of between 1.0 μm and 1.82 μm. It is then validated at pulse on time settings of 244 ns and 458 ns, which generated average recast layer thicknesses of 1.18 μm and 1.56 μm, respectively. Thus, the numerical model developed using the multiple discharge approach is suitable for estimation of recast layer thicknesses in micro-EDM.

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