Print ISSN: 1681-6900

Online ISSN: 2412-0758

Keywords : EDM


Investigation the Effect of Negative Polarity of Surface Roughness and Metal Removal Rate During EDM Process

Shahd A. Taqi; Saad K. Shather

Engineering and Technology Journal, 2020, Volume 38, Issue 12, Pages 1852-1861
DOI: 10.30684/etj.v38i12A.1591

The Electro discharge machine that named (EDM) is used to remove the metal from the workpiece by spark erosion. The work of this machining depends on the multiple variables. One of the most influential variants of this machine is the polarity, the material of the electrode, the current and the time pulses. Essentially the polarity of the tool (electrode) positive and the work piece is negative, this polarity can be reversed in this paper was reversed the polarity that was made the tool (electrode) negative and the work piece was positive. The aim of this paper was focused on the influence of reversed the polarity (negative) with changing the electrode metal (copper and graphite) on the surface roughness and metal removal rate by using different parameters (current and pulses of time). Experiments show that: the copper electrode gives (best surface roughness 0.46 μm when the current 5 Am and Ton 5.5 μs) and (worst surface roughness 1.66 μm when the current is 8 A and Ton 25 μs). And give (best values of the MRR 0.00291 g/min when the current is 8 and Ton 25 μs) and (The lowest values of MRR (0.00054 g/min when current is 5 and Ton 5.5 μs). The graphite electrode gives (best surface roughness 2.07 μm when the current 5 Am and Ton 5.5 μs) and (worst surface roughness 4.17 μm when the current is 8 A and Ton 25 μs). And give (best values of the MRR 0.05823 g/min when the current is 8 and Ton 25 μs) and (The lowest values of MRR (0.00394 g/min when current is 5 and Ton 5.5 μs).

Effect of SiC-Cu Electrode on Material Removal Rate, Tool Wear and Surface Roughness in EDM Process

Yousif Q. Laibi; Saad K. Shather

Engineering and Technology Journal, 2020, Volume 38, Issue 9, Pages 1406-1413
DOI: 10.30684/etj.v38i9A.552

Electrical discharge machining (EDM) is one of the most common non-traditional processes for the manufacture of high precision parts and complex shapes. The EDM process depends on the heat energy between the work material and the tool electrode. This study focused on the material removal rate (MRR), the surface roughness, and tool wear in a 304 stainless steel EDM. The composite electrode consisted of copper (Cu) and silicon carbide (SiC). The current effects imposed on the working material, as well as the pulses that change over time during the experiment. When the current used is (8, 5, 3, 2, 1.5) A, the pulse time used is (12, 25) μs and the size of the space used is (1) mm. Optimum surface roughness under a current of 1.5 A and the pulse time of 25 μs with a maximum MRR of 8 A and the pulse duration of 25 μs.

Enhancement of EDM Performance by Using Copper-Silver Composite Electrode

Saad K. Shather; Abbas F. Ibrahim; Zainab H. Mohsein; Omar H. Hassoon

Engineering and Technology Journal, 2020, Volume 38, Issue 9, Pages 1352-1358
DOI: 10.30684/etj.v38i9A.1549

Discharge Machining is a non-traditional machining technique and usually applied for hard metals and complex shapes that difficult to machining in the traditional cutting process. This process depends on different parameters that can affect the material removal rate and surface roughness. The electrode material is one of the important parameters in Electro –Discharge Machining (EDM). In this paper, the experimental work carried out by using a composite material electrode and the workpiece material from a high-speed steel plate. The cutting conditions: current (10 Amps, 12 Amps, 14 Amps), pulse on time (100 μs, 150 μs, 200 μs), pulse off time 25 μs, casting technique has been carried out to prepare the composite electrodes copper-sliver. The experimental results showed that Copper-Sliver (weight ratio70:30) gives better results than commonly electrode copper, Material Removal Rate (MRR) Copper-Sliver composite electrode reach to 0.225 gm/min higher than the pure Copper electrode. The lower value of the tool wear rate achieved with the composite electrode is 0.0001 gm/min. The surface roughness of the workpiece improved with a composite electrode compared with the pure electrode.

Influence of Polarity of Electro Discharge Machine (EDM) on Surface Roughness (SR) and Metal Removal Rate (MRR) of Low Carbon Steel

Shahd Taqi; Saad K. Shather

Engineering and Technology Journal, 2020, Volume 38, Issue 7, Pages 975-983
DOI: 10.30684/etj.v38i7A.469

Electro discharge machining (EDM) is one of a thermal process that is used for remove of metal from the workpiece by spark erosion. The work of this machine depends on multiple variables. One of the more influential variants on this machine is the change of polarity and the use of this variable is not wide and the research depends on the polarity of the machinist. Essentially, the polarity of the tool (electrode) is positive and the workpiece is negative, this polarity can be reversed. This paper focuses on the influence of changing the polarity (positive and negative) on the surface roughness and metal removal rate by using different parameters (current, voltages, polarity and Ton). Experiments show that the positive electrode gives (best surface roughness = 1.56 μm when the current = 5 Am and Ton = 5.5 μs) and (best metal removal rate = 0.0180 g/min when the current = 8 Am and Ton = 25 μs). Negative electrode gives (best surface roughness = 0.46 μm when the current = 5 Am and Ton = 5.5 μs) and (best metal removal rate = 0.00291 g/min when the current = 8 Am and Ton = 25 μs).

Influence of EDM Parameters on the Appearance of Recast Layer

S.K. Shather; A.F. Ibrahim; N. Jammal

Engineering and Technology Journal, 2017, Volume 35, Issue 7, Pages 694-700

Electrical discharge machining (EDM) is one of non-traditional methods employed to produce complicated forms of electrical conductive materials. This process can be applied to materials difficult to machine with traditional methods. Thus, the study and analysis of EDM variables play an important role to improve the yield, and safety of a surface. This research aims at study and analyze influence of pulse current (Ip) (10, 16, 22) Amp, pulse on time (Ton) (50, 100,150) μs and pulse off time (Toff) (25, 50, 75) μs, (keeping other parameters fixed) on a Recast Layer Thickness (RLT) for machining (AISI 1018 mild carbon steel) using Response Surface Methodology (RSM) within “Minitab 17” for designing of experiments. Optical microscopy and scanning electron microscopy (SEM) was used. Experiments proved that minimum RLT was 5.2 μm at Ip, Ton and Toff at 10Amp, 50 μs and75 μs, respectively. The results also indicated that RLT increased with the increased (Ip and Ton) and decreased in Toff.

Optimization of MRR and Surface Roughness for 7024 AL-alloy in EDM Process

M.M. Abdulrazaq; S.K. Ghazi

Engineering and Technology Journal, 2017, Volume 35, Issue 5, Pages 546-553

Electro discharge machining is major non-traditional operations for cutting the materials due to its suitability and benefits. The experimental work of this paper deals with electrico discharge machining (EDM). A system for machining in this process has been developed. Many parameters are studied such as current, time on and time off. Different current rates are used ranging from (30, 36 and 42) Amp, found that low current gives less material removal rates and good surface roughness. The results showing that maximum MRR is achieved (0.525) mm3/min when machining current (42), time on (150), and time off (50) while good surface roughness (2.11 μm) when machining current (30), time on (50), and time off (25).The level of importance of the machining parameters for surface roughness and material removal rate is determined by using Taguchi design experiments and analysis of variance (ANOVA).

Prediction of Surface Roughness and Material Removal Rate for 7024 AL-Alloy in EDM Process

Abbas Fadhil Ibrahim; Mostafa Adel Abdullah; Safaa Kadhim Ghazi

Engineering and Technology Journal, 2016, Volume 34, Issue 15, Pages 2796-2804

This paper studies prediction the values of MRR and surface roughness in Electrical discharge operations. It is a operation in which the material removal rate is machined with elevation spark in the midst work piece and electrode sunken through dielectric solution.Through use Taguchi found that the accuracy of the measured and prediction values that have been is 93% and 99% for each of the MRR and surface roughness respectively. The effect of different Electrical discharge machining factors are (Gap, pulse off time and pulse on time) to predict the (material removal rate) and (roughness). Note that connected pole that was used is copper. From (ANOVA) found that the large parameter effect on MRR is pulse-on 65% and pulse-off 25% while large parameter effect for surface roughness is pulse-on 96% . The least influential parameter for metal removal rate is the gap and the least influential parameter for surface roughness is pulse-off and Gap.

Improving the Metal Removal Rate (MRR) in Electro Discharge Machining by Additives Powder

Saad Kariem Shather; Ruaa Amer salim

Engineering and Technology Journal, 2016, Volume 34, Issue 14, Pages 2766-2774

Electro discharge machining (EDM) is one of non-traditional machining processes which is used in important application. This paper has focused on improving material removal rate by adding powders (Al2O3 particle size 15-35m) and (SiO2 particle size 20-30m) to kerosene solution through EDM process with different ratios (0.1, 0.14, 0.18 to 0.25 g) particle size for each liter using different values of currents (8, 16 and 30 Amp) and (140 Volt) and (Toff, Ton 25 and 37 μSec),
Medium carbon steel is used as a workpeice and copper as electrode, the material removal rate (MRR). It has been found that maximum MRR was (0.2969) g/min when adding SiO2 powder (0.25)g/l and maximum MRR was (0.2781)g/min when adding Al2O3 powder (0.25)g/l, the Minitab model program was used to predict the MRR which gives a good result and agreement with experiments 99%.

Effect of Powder Concentration in PMEDM on Machining Performance for Different Die steel Types

Maan Aabid Tawfiq; Azzam Sabah Hameed

Engineering and Technology Journal, 2015, Volume 33, Issue 9, Pages 2174-2186

Electric discharge machining(EDM) is one of the nonconventional machining process which has been used in manufacturing complex shapes on hard material that are difficult to cut by conventional processes, especially, die casting, parts of aircraft, medical equipment, automobile industries. Powder mixed electric discharge machining(PMEDM), has emerged as one of the advanced techniques in the direction of the enhancement of the capabilities of EDM. The objective of the present research is to study the influence of process parameters such as peak current, pulse on time, manganese,aluminum, and aluminum-manganese mixing powder concentration on machining performance of different types of die steel (AISID3,AISID6,H13)with round copper electrode(20 mm diameter) on machining performance. Experiments have been designed using Taguchi method. Taguchi L27 orthogonal array has been selected for five factors 3 levels design. The machining performance has evaluated in terms of metal removal rate (MRR).It is found that manganese powder concentration mixed in dielectric fluid significantly affect the machining performance, maximum (MRR) is obtained at a high peak current(12 A), pulse on(200µs), and (4g/L) concentration of manganese powder,the optimum MRR is 17.56mm3/min with percent of error about 5.61% compared with the Experimental value.

The Influence of Current & Pulse off Time on Material Removal Rate and Electrode Wear Ratio of Steel 304 in EDM

Shukry Hammed Aghdeab; Vian Nihad Najm

Engineering and Technology Journal, 2015, Volume 33, Issue 8, Pages 1845-1856

EDM (Electric Discharge Machining)machine was used for machining of conducting cutting materials such as steel 304in dielectric solution (diesel fuel) by supplied byDC current values (10, 20, 30, 42 and 50A). Voltage of (140V) was used to cut (1) mm thickness.
The experimental results reveal that the material removal rate enhanced by increasing the current values also show that the Electrode wear ratio rises with increase in the current values. It is also concluded that the material removal rate reduces with increasing the pulse off time values and the electrode wear ratio.

Study the Effect of the Graphite Powder Mixing Electrical Discharge Machining on Creation of Surface Residual Stresses for AISI D2 Die Steel Using Design of Experiments

Ahmed Naif Al-Khazraji; Samir Ali Amin; Saad Mahmood Ali

Engineering and Technology Journal, 2015, Volume 33, Issue 6, Pages 1399-1415

This paperattempted to study the induced surface residual stressesduethe effect of Electrical discharge machining (EDM) input parameters, (the pulse current,the pulse-on time and the type of electrode).The work includedthe use of two types of electrode, the copper and graphite as well as using or without using the graphite powder mixing with the kerosene dielectric (PMEDM) for machining AISI D2 dies steel. The response surface methodology (RSM) was usedfor design the experimental work matrices. The analysis of variance (ANOVA) was used, and models were builtto predict the surface residual stresses.The obtained results showed that the minimum tensile surface residual stresses obtained when using the copper electrodeswith pulse current (22 A) and pulse on duration (40 µs) when working with kerosene dielectric alone and (8 A) with (120 µs) when working with graphite powder mixing. The results concluded that the using of graphite electrodes and kerosene dielectric alone or with powder mixing induced minimum residual stresses with pulse current (22 A) and pulse on duration (120 µs). The copper elec-trodes with kerosene dielectric and graphite powder mixing improved the induced tensile residual stresses by about (80 %) lower than when using kerosene dielectric alone and about (50%) lower than with graphite electrodes and the kerosene dielectric alone or with graphite mixing powder.

Experimental Investigations of Hole - EDM to Optimize ElectrodeWear through Full Factorial of Design of Experiment

Shukry H. Aghdeab; Laith A. Mohammed

Engineering and Technology Journal, 2015, Volume 33, Issue 2, Pages 372-379

Electrical discharge machining (EDM) is a process where the material removal of the workpiece is achieved through high frequency sparks between the tool (electrode) and the workpiece immersed into the dielectric solution. It is commonly used to produce moulds and dies, to drill small, burr free holes and to make prototypes for the aerospace and electronics markets. In this work, micro-holes were fabricated on copper alloys by using EDM. The output responses investigated was electrode wear weight (EWW). Full factorial of Design of Experiment (DOE) module in Minitab was used as a principal methodology to examine the effects of current and machining time over output responses. Experimental results indicate that the EWW was mainly affected by current, and can be reduced by increasing the current parameter. Minimum EWW (0.12gm) obtained at 10A.

Optimizing Overcut Parameter of Micro-Holes Machining by EDM Using Taguchi Method

Laith A. Mohammed; Shukry H. Aghdeab

Engineering and Technology Journal, 2014, Volume 32, Issue 2, Pages 298-304

In this paper Taguchi method was performed to estimate the optimum overcut parameter for Electro Discharge Machining (EDM) to obtain micro-holes of copper alloy workpieces. Taguchi method is used to formulate the experimental layout, to analyses the effect of each parameter on the machining characteristics and to predict the optimal choice for each machining parameter (current, gap distance and machining time), and analyzed the effect of these parameters on the overcut parameter. The
analysis shows that, the current significantly affects the overcut parameter.

Studying the Affect of Current on (MRR) and (EW) in Electrical Discharge Machining (EDM)

Ahmed Bassil Abdulwahhab; Shukry Hamm; Maan Aabid Tawfiq

Engineering and Technology Journal, 2013, Volume 31, Issue 17, Pages 3298-3311

The experimental work of this study leads with electro discharge machining
(EDM). A system for machining in this process has been developed. Many
parameters are studied such as current, dielectric fluid, thickness of the workpiece.
The main aim of this work is to calculate the metal removal rate (MRR), electrode
wear (EW) using copper electrode when machining stainless steel 304 specimens
of thickness (0.4, 0.5, 1mm). Different current rates are used ranging from (10, 15,
20, 25, 30)Amp, and using tap water as a dielectric solution, it found that low
current gives a less material removal rate and electrode wear while high current
gives a high material removal rate and electrode wear, the dielectric fluid is
changed in order to enhance results. The results show that maximum MRR is
achieved 1.01164mm3/min when machining thickness of workpiece 0.4mm and
using electrode of copper metal which gives minimum EW 0.04gm, while when
using thickness 0.5mm it gives MRR 0.43828mm3/min and EW 0.12gm, for
thickness 1mm the MRR 0.33964mm3/min and EW is 0.11gm. The results show
also that using distilled water as a dielectric fluid with copper electrode and
thickness of workpiece 0.5mm gives minimum MRR 0.13854mm3/min and less
EW 0.08gm compared with using tap water.

Studying the Parameters of EDM Based Micro- Cutting Holes Using ANOVA

Shukry H. Aghdeab; Laith A. Mohammed

Engineering and Technology Journal, 2013, Volume 31, Issue 15, Pages 2876-2884

Micro -EDM is one of an important method in machining holes which is used in wide
applications to fabricate medical devices and small dies. This work study the process of
producing micro holes for copper alloy workpieces using, stainless steel electrode
and dielectric solution (tap water), using DC current and low voltage (70V) to cut
(0.7mm) thickness of copper (Cu) alloy workpieces in order to obtain the micro holes.
This work included an experimental work for electrical discharge machining
(EDM) to produce micro holes with different diameters (400, 300, 210, 200, 120,
100, 85, 75, 70) μm.
The objective of this work is to obtain an optimal setting of EDM parameters to
produce micro holes in copper alloy to achieve the optimal values of required holes
diameters.
A regression model has been developed to represent this process. An approach
has been made to optimize the process parameters (current, gap distance, machining
time) using ANOVA analysis. This analysis was performed to obtain the most
significant factors influencing the production of micro holes.

Experimental Investigations of Hole - EDM to Optimize Electrode Wear through Full Factorial of Design of Experiment

Shukry H. Aghdeab; Laith A. Mohammed

Engineering and Technology Journal, 2013, Volume 31, Issue 13, Pages 2572-2579

Electrical discharge machining (EDM) is a process where the material removal of the
workpiece is achieved through high frequency sparks between the tool (electrode) and the
workpiece immersed into the dielectric solution. It is commonly used to produce moulds
and dies, to drill small, burr free holes and to make prototypes for the aerospace and
electronics markets. In this work, micro-holeswere fabricated on copper alloys by using
EDM. The output responses investigated was electrode wear weight (EWW). Full
factorial of Design of Experiment (DOE) module in Minitab was used as a principal
methodology to examine the effects of current and machining time over output responses.
Experimental results indicate that the EWW was mainly affected by current, and can be
reduced by increasing the current parameter. Minimum EWW (0.12gm) obtained at 10A.

Study the Effect of Electrical Current on Average Surface Roughness of Borosilicate Glass at EDM Machining and Comparison Using Matlab Program

Shukry H. Aghdeab; Ahmed A. Abulwahhab

Engineering and Technology Journal, 2011, Volume 29, Issue 6, Pages 1157-1165

Machining of electrically non-conducting materials like glass is still a major
problem. The principle of electric arc was used to generate high electrical
discharge (spark) at high currents to machine non-conducting materials at any
hardness.
EDM system was build for machining of non-conducting cutting materials
such as glass including the use of powder (graphite) mixed for dielectric solution
(tap water) by supplied DC current values (200, 250, 300, 350 and 400A). Voltage
of (70V) was used to cut 3mm thickness of borosilicate glass (BSG) to obtain the
average surface roughness (Ra) of about (0.003-0.012μm).
Matlab program has been used to investigate the process control for EDM that
could the Ra experimental and theoretical with accuracies of 94.236, 94.034,
96.628 and 92.875% respectively.
From the reading of the magnitude of the roughness it was found that differences
between the theoretical and experimental values for 3mm thickness of BSG was
never exceed (8%).

Effect of Current on Average Surface Roughness of Borosilicate Glass at EDM Machining and Comparison with Numerical Programs

Wathik I. Mahdi; Maan A. Tawfiq; Shukry H. Aghdeab

Engineering and Technology Journal, 2009, Volume 27, Issue 6, Pages 1026-1038

Machining of electrically non-conducting materials like glass is still a major problem. The principle of electric arc was used to generate high electrical discharge (spark) at high currents to machine non-conducting materials at any hardness, which is a new approach.
EDM system was build for machining of non-conducting cutting materials such as glass with new technology including the use of powder (graphite) mixed for dielectric solution (tap water) by supplied AC current values (200, 250, 300, 350 and 400A). Voltage of (70V) was used to cut 3mm thickness of borosilicate glass (BSG) to obtain the average surface roughness (Ra) of about (0.003-0.012μm) but the Ra before the machining was (0.005-0.006μm).
Numerical program called "Simulent" has been used to investigate the process control for EDM by using GN, BPN, PN and VQN that could predict the Ra with accuracies of 94.236, 94.034, 96.628 and 92.875% respectively from training data sets.
The differences on the Ra at different network models for 3mm thickness of BSG never exceed (8%) from testing data sets while the comparison of numerical results with experimental results of Ra among the measured values and prediction various network models, shows a differences between (1-8%).
The best predication accuracy is by the use of PN than other network models.