A literature review on machining of different materials with EDM

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I JSRD - I nternational Journal for Scientifi c Research & Development| Vol. 3, I ssue 12, 2016 | ISSN (onli ne): 2321-0613

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A Literature Review on Machining of Different Materials with EDMAbhimanyu Chauhan1 Deepak Gupta2

1M.Tech. Student 2Assistant Professor2Department of Mechanical Engineering

1,2Glaxy Global group of Institutes Abstract — This paper discuss of literature review of different

materials on EDM. Today EDM has major contribution inindustries. Basically EDM is automated operating machine

which are based on code letters, numbers and special

characters.

Key words: CNC, MRR, Taguchi, SR, optimization

I. I NTRODUCTION

Electrical Discharge Machine (EDM) is an electro-thermal

non-traditional machining Process, where electrical energy is

used to generate electrical spark and material removal mainlyoccurs due to thermal energy of the spark. EDM is mainly

used to machine where are difficult-to-machine materials and

high strength temperature resistant alloys. EDM can be usedto machine difficult geometries in small batches or even on

job-shop basis.

Types of EDM: Basically, there are two different types of

EDM:

1) Die-sinking

2) Wire-cut

Working principle of EDM: At the beginning of

EDM operation, a high voltage is applied across the narrow

gap between the electrode and the work piece. This high

voltage induces an electric field in the insulating dielectricthat is present in narrow gap between electrode and work

piece. This causes conducting particles suspended in the

dielectric to concentrate at the points of strongest electricalfield. When the potential difference between the electrode

and the work piece is sufficiently high, the dielectric breaks

down and a transient spark discharges through the dielectricfluid, removing small amount of material from the work piece

surface.

II.

LITERATURE REVIEW

Lin et al. (2009) investigated machining performance of

conductive ceramics (Al2O3 + 30vol% TiC) using electrical

discharge machining (EDM) is the aim of this work. TheEDM machining parameters such as machining polarity, peak

current, auxiliary current with high voltage, pulse duration,

no load voltage, and servo reference voltage were chosen to

explore the effects on material removal rate (MRR), electrode

wear rate (EWR), and surface roughness (SR). The L18

orthogonal array based on the Taguchi experimental methodwas adopted to determine EDM machining characteristics.

Bhaduri et al. (2009) investigated electro discharge

machining (EDM) has been carried out to machine thematerial. Energy dispersive X-ray spectroscopy and X-ray

diffraction analysis have also been carried out on the

composite matrix to verify the presence of two

distinguishable phases of TiN and Al2O3. The present article

reports the effects of EDM process parameters on material

removal rate, electrode wear rate, radial overcut, and taper

angle while machining TiN – Al2O3 composite. The

characteristic features of the EDM process are explored

through Taguchi L9 orthogonal array design – based

experimental studies with various process parametric

combinations.

Kumar et al. (2010) studied comprehensive history,

mechanism of AEDM process, and reviews researchliterature in this area. The last part of this article outlinestrends for future AEDM research directions. In recent years,

researches have emphasized on increasing machining

performance coupled with deliberate surface treatments.

Additive mixed electrical discharge machining (AEDM) is a

novel innovation for enhancing the capabilities of electrical

discharge machining process in this direction.Chakravorty et al. (2012) studied two sets of past

experimental data on EDM processes are analyzed using four

PCA-based optimization methods. The optimization

performances of these methods are compared with the results

achieved by the past researchers, considering expected total

signal-to-noise (S/N) ratio as the utility measure. It is foundthat the PCA-based approaches, in general, lead to better

optimization performance and among the four PCA-based

approaches, PCA-based proportion of quality loss reduction

(PQLR) method results in the best optimization performance.

So the PCA-based PQLR method can be applied for

optimizing multiple responses of EDM process.

Meena and Azad (2012) investigated micro-electric

discharge machining (micro-EDM) of Ti-6Al-V alloy with

tungsten carbide electrode has been performed. Ti-6Al-4V,

which is difficult to machine via conventional machining

techniques, however, can be easily machined via EDMmachining, with careful selection of machining parameters

for getting optimum results. In this study, the effect of variousinput parameters current, voltage, frequency, and width, on

output parameter viz., metal removal rate (MRR), tool wear



A Literature Review on Machining of Different Materials with EDM

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rate (TWR), and overcut (OC) are studied. Grey relational

analysis and analysis of variance (ANOVA) have been

performed to optimize the levels of input parameters.Arunkumar et al. (2012) studied experimental work

carried out in electrical discharge machining (EDM) of EN31

(air hardened steel) using three different tool materials

namely copper, aluminium and EN24, and also the problems

involved in using graphite and brass as tool material. The

machining process was carried out at three different supplycurrent levels, flushing pressure levels and pulse-on time and

their influence on surface roughness, material removal rate,

tool wear rate and taper.

Prajapati and Prajapati (2013) investigated

performance of different electrode Materials on EN-9 work

piece with EDM process. Approach: The electrode materials

were graphite, copper and Brass. The important parameters

were peak current, pulse on time, pulse off. A work piece

material was EN-9. Results: The results show that the

Graphite electrode gives higher MRR than other two

Electrodes. Brass electrode gives better surface finishing

among three electrodes. Powder electrode gives the better

MRR and high SR more than solid electrode.

Raghuraman et al. (2013) investigated the optimal

set of process parameters such as current, pulse ON and OFF

time in Electrical Discharge Machining (EDM) process to

identify the variations in three performance characteristicssuch as rate of material removal, wear rate on tool, and

surface roughness value on the work material for machining

Mild Steel IS 2026 using copper electrode. Based on the

experiments conducted on L9 orthogonal array, analysis has

been carried out using Grey Relational Analysis, a Taguchi

method. Response tables and graphs were used to find theoptimal levels of parameters in EDM process. The

confirmation experiments were carried out to validate the

optimal results. Thus, the machining parameters for EDM

were optimized for achieving the combined objectives of

higher rate of material removal, lower wear rate on tool, and

lower surface roughness value on the work materialconsidered in this work.

III. IMPORTANT PARAMETERS OF EDM

In EDM there are many parameters used which are

responsible for the proper machining and the quality of final

product but in the present study we are using four major

parameters of EDM which affects the final quality these are

given in below: -

A.

Pulse-On Time:

It is the time during which the machining takes place.

Material removal is directly proportional to the energy

applied during the pulse-on time. The length of pulse-on time

controls that energy. The material removal rate increase with

pulse-on time but after a certain extent it starts decreasing.Every material has different optimum pulse on combination.

When the tool electrode is at negative potential, material

removal from the anode (work piece) takes place by

bombardment of high energy electrons ejected from the tool

surface. At the same time positive ions move towards the

cathode. When small pulses-on time is used, material removal

by electron bombardment is predominant due to the higherresponse rate of the less massive electrons. However, when

longer pulses are used, energy sharing by the positive ions is

predominant and the material removal rate decreases. When

the electrode polarities are reversed, longer pulses are found

to produce higher MRR.

B. Pulse Off Time:

The pulse off time is necessary for the proper machining. For

completing the cycle it is necessary, sufficient off-time is

allowed before the start of the next cycle. Pulse off time will

affect the stability of the cut and speed. Shorter the off-time,the faster will be the machining operation. However, if theoff-time is too short, the removed work piece material will

not be swept away with the flow of the dielectric and the fluid

will not be deionized. This will cause the next spark to be

unstable. Unstable conditions cause erratic cycling and

retraction of the advancing servo. Off-time must be greater

than the deionization time to prevent continued sparking atone point.

C. Peak Current:

This is the most important parameter for machining any work

material in EDM. It is measured in units of amperage. It is the

amount of power used in discharge machining. Higher currentwill increase the pulse energy. As the current increases thematerial removal rate also increases but it also affect the

surface finish and electrode wear rate. As the current

increases, electrode wears rate increase which means poor

surface finish. During the pulse-on time the current increases

it reaches to level that is called peak current.

D. Discharge Voltage:

In the EDM, discharge voltage is related to the spark gap and

breakdown strength of the dielectric. Before current can flow,

the open gap voltage increases until it creates an ionization

path through the dielectric. Once the current starts to flow,

voltage drops and stabilizes at the working gap level. The preset voltage determines the width of the spark gap between

the leading edge of the electrode and work piece. Higher

voltage settings increase the gap, which improves the flushing

conditions and helps to stabilize the cut. Tool wear rate and

surface roughness increases with increase in open circuit

voltage because electric field strength increases.

IV. TAGUCHI TECHNIQUE

Taguchi emphasizes pushing quality back to the design stagesince inspection and statistical quality control can never fully

compensate for a bad design. The three steps of quality by

design are system design, parameter design, and tolerance

design. System design requires technical knowledge fromscience and engineering. In the parameter design step, thespecific values for system parameters are determined.

Tolerance design is used to determine the best tolerances for

the parameters. The steps suggested by Taguchi are:



A Literature Review on Machining of Different Materials with EDM

(IJSRD/Vol. 3/Issue 12/2016/276)


V. CONCLUSION

From the above discussion we found that most of theresearchers had taken input parameters (Pulse-on Time, Pulse

off Time, Peak current and Discharge Voltage) facing output

parameters SR, MRR and EWR. In this paper, studied the

different approaches for the machining parameters with the

optimum utilization of these parameters. Now these days

these parameters play a very vital role for the machining and

utilized in the industries.

R EFERENCES

[1] Bhaduri, D., Kuar, A.S.,Sarkar, S., Biswas, S.K. and

Mitr a S. (2009), “Electro Discharge Machining of

Titanium Nitride-Aluminium Oxide Composite for

Optimum Process Criterial Yield” Materials and

Manufacturing Processes, Vol. 24, pp. 1312 – 1320.

[2] Bhuyan, R.K., Routara, B.C., Parida, A.K. and Sahoo,A.K.(2014), " Parametric optimization of Al-Sic12%

metal matrix composite machining by electrical

discharge machine" All India Manufacturing

Technology, Design and Research Conference.

[3] Chakravorty, R., Gauri, S.K. and Chakraborty, S.(2012),

“Optimization of Correlated Responses of EDM

Process” Materials and Manufacturing Processes, Vol.

27, pp. 337 – 347.

[4] Darji, V. and Darji, Y.A. (2014), "Investigation on theEffect of Process Parameters For EN31 material By

EDM using full factorial method" International Journal

For Research in Applied Science and Engineering

Technology, Vol. 2 Issue 5, pp. 514-521.

[5] Kasdekar, D.K., Parashar, V., Singh, J. and Gour, M.K.

(2014), “Taguchi Method and ANOVA: An Approachfor Selection of Process Parameters of EDM of EN-353

Steel” International Journal of Emerging Technology

and Advanced Engineering, Vol. 4, Issue 6, pp. 313-321.

[6] Kumar, A., Maheshwari, S., Sharma, C. and Beri,

N.(2010), “Research Developments in Additives Mixed

Electrical Discharge Machining (AEDM): A State of Art

Review” Materials and Manufacturing Processes, Vol.

25, pp. 1166 – 1180.

[7] Kumar, A., Bedi, K.S., Dhillo, K.S. and Singh, R.,"

Experimental Investigation of Machine parameters For

EDM Using U shaped electrode of EN-19 tool steel" Vol.

1, Issue 4, pp.1674-1684.

[8]

Lin, Y.C., Wang, A.C., Wang, D.A. and Chen, C.C.

(2009), “Machining Performance and Optimizing

Machining Parameters of Al2O3 – TiC Ceramics Using

EDM Based on the Taguchi Method” Materials and

Manufacturing Processes, Vol. 24, pp. 667 – 674.[9] Manjaiah, M., Narendranath, S. and Basavarajappa,

S.(2014), “A review on machining of titanium based

alloys using EDM and WEDM” Reviews on advanced

materials science, Vol. 36, pp. 89-111.

[10] Mishra, D.M., Bhatia, A. and Rana, V.(2014), “ Study on

Electro Discharge Machining (Edm)”The InternationalJournal Of Engineering And Science, Vol. 3, Issue 2, pp.

24-35.

A literature review on machining of different materials with EDM

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