Optimization of Process Parameters of Powder Mixed Dielectric EDM for MRR and Ra
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This document presents an experimental study on optimizing process parameters for powder mixed dielectric electric discharge machining (PMEDM) to maximize material removal rate (MRR) and minimize surface roughness (Ra). Taguchi methodology was used to design experiments using an L9 orthogonal array with discharge current, duty factor, spark gap, and graphite powder concentration as input variables. Regression analysis and grey relational analysis were conducted on the experimental results. The optimal parametric combination found was discharge current of 20A, duty factor of 5%, spark gap of 0.05mm, and graphite powder concentration of 6g/l, achieving a predicted MRR of 68.43mm3/min and Ra of 7.28μm,
![International Research Journal of Engineering and Technology (IRJET) e-ISSN: 2395-0056
Volume: 04 Issue: 11 | Nov -2017 www.irjet.net p-ISSN: 2395-0072
© 2017, IRJET | Impact Factor value: 6.171 | ISO 9001:2008 Certified Journal | Page 1040
3 Spark gap (SG)
4 Concentration of dielectric (C)
2) Output parameters
1 Material removal rate (MRR)
2 Surface Roughness ( Ra)
Graphite powder- The grain size of graphite powder is
15microns.
Tool selection-The selected tool is of pure copper. The
length of the tool is 80 mm and diameter of tool is 20 mm. In
most of the industries for EDM, the tool used is of copper
material. Since copper is cheap as compared to graphite and
readily available in the market.
Work piece selection- Material EN-8 is medium carbon
steel has good tensile strength and usually used in
applications such as shafts, studs,stressedpins,keys etc.The
dimensions of work piece are70x25x6 mm.
Dielectric (EDM oil) - The dielectric used in my
experimentation work is EDM oil. The concentration of this
dielectric is varied by adding graphite powder. This affects
the material removal rate and surface finish
2. RESULTS AND DISSCUSSION.
The experimental results are given below.
Expt
no.
Discha
rge
curren
t [Ip]
Duty
factor
[τ]
Spark
gap
SG
Conc.
dielec
tric
[C]
MRR
mm3
/min
Ra
µm
1 10 5 0.05 0 26.63 5.73
2 10 7 0.1 3 28.09 5.61
3 10 9 0.15 6 29.81 5.5
4 15 5 0.1 6 41.58 6.6
5 15 7 0.15 0 35.40 6.7
6 15 9 0.05 3 40.21 6.82
7 20 5 0.15 3 68.47 7.15
8 20 7 0.05 6 70.88 7.23
9 20 9 0.1 0 69.85 7.45
Table 1: Experimental results
3. REGRESSION ANALYSIS
The regression equation for MRR is,
MRR = - 18.9 + 4.16 Discharge current + 0.27 Duty Factor -
13.5 spark gap + 0.577 concentration
The regression equation for Ra is,
Ra = 4.10 + 0.166 Discharge current + 0.0242 Duty Factor -
1.43 spark gap - 0.0306 concentration
4. GREY RELATINAL ANALYSIS
This approach converts a multiple- response- process
optimization problem into a single response optimization
situation.
MeanofS/NratioforOGRGRD
201510
0
-1
-2
-3
-4
975
0.150.100.05
0
-1
-2
-3
-4
630
Discharge current(Ip) Duty factor [t]
Spark gap (SG) Concentration of dielctric (C)
Main Effects Plot (data means) for S/N ratio for OGRGRD
Graph 1. S/N Ratio plot of overall grey relational grade
With the help of the graph , optimal parametric combination
has been determined. The optimal factor setting becomes as
Ip3, τ1 , SG1, C3.
5. CONFIRMATORY EXPERIMENTS
Optimal settings
Prediction Experimental
%Err
or
Level of
factors
Ip=20A, τ=5,
SG=0.05mm,
C=6g/l
Ip=20A, τ=5,
SG=0.05mm,
C=6g/l
MRR(mm3
/min)
68.43 69.33 1.29
Ra(µm ) 7.28 7.17 1.51
Table 2. Results of confirmatory experiment](https://image.slidesharecdn.com/irjet-v4i11184-171211064402/85/Optimization-of-Process-Parameters-of-Powder-Mixed-Dielectric-EDM-for-MRR-and-Ra-2-320.jpg)
![International Research Journal of Engineering and Technology (IRJET) e-ISSN: 2395-0056
Volume: 04 Issue: 11 | Nov -2017 www.irjet.net p-ISSN: 2395-0072
© 2017, IRJET | Impact Factor value: 6.171 | ISO 9001:2008 Certified Journal | Page 1041
5. CONCLUSION
The material removal of the EDM process is rather low,
especially in the case of EDM where the total volume of a
cavity has to be removed. If the EDM is operated at the
optimum setting of electrical parametersthenthisdrawback
can be minimized. While machining the material EN8, the
industrialist can directly use the optimum values so that the
material removal rate will be maximum and Ra value will be
minimum. The common optimum values for both MRR and
Ra can be easily obtained by the use of grey relational
analysis method
6. REFERENCES
[1] H.K.Kansal , S.Singh and Pradeep Kumar, “Effect of
Silicon Powder Mixed EDM on Machining Rate of AISID2Die
Steel”, Journal of ManufacturingProcessesVol.9/No.12007.
[2] G. Bharath Reddy, G.Naveen Kumar and Chandrashekar,
“Experimental Investigation on Process Performance of
Powder Mixed Electric Discharge Machining of AISI D3 steel
and EN-31 steel” International Journal of Current
Engineering and Technology, India .Accepted 02 May 2014,
Available online 01 June 2014, Vol.4, No.3 (June 2014).
[3]Sanjeev Kumar,∗, Uma Batra,“Surface modification of die
steel materials by EDM method using tungsten powder-
mixed dielectric” Journal of ManufacturingProcesses (2012)
35-40.
[4] Xue Bai, Qinhe Zhang,∗, Jianhua Zhang Dezheng Kong,
Tingyi Yang “Machining efficiency of powder mixedneardry
electrical discharge machining based on different material
combinations of tool electrode and workpiece
electrode”Journal of Manufacturing Processes 15 (2013).
[5] F.Q. Hu, F.Y. Cao, B.Y. Song, P.J. Hou, Y. Zhang, K. Chen, J.Q
surface properties of SiCp/Al composite by powder-mixed
EDM www.sciencedirect.com ( 2013) 101 – 106.
[6] Ryota Toshimitsua, Akira Okada,*, RyojiKitada and
Yasuhiro Okamoto“ Improvement in SurfaceCharacteristics
by EDM with Chromium Powder Mixed Fluid” Available on
www.sciencedirect.com
[7] W.S. Ghao, Q. G. Meng, Z. L. Wang “application of research
on powder mixed edm in rough machining”. journal of
material processing technology(129-2002).](https://image.slidesharecdn.com/irjet-v4i11184-171211064402/85/Optimization-of-Process-Parameters-of-Powder-Mixed-Dielectric-EDM-for-MRR-and-Ra-3-320.jpg)
Optimization of Process Parameters of Powder Mixed Dielectric EDM for MRR and Ra
- 1. International Research Journal of Engineering and Technology (IRJET) e-ISSN: 2395-0056 Volume: 04 Issue: 11 | Nov -2017 www.irjet.net p-ISSN: 2395-0072 © 2017, IRJET | Impact Factor value: 6.171 | ISO 9001:2008 Certified Journal | Page 1039 Optimization of Process Parameters of Powder Mixed Dielectric EDM for MRR and Ra Mrs. V.D. Chame1, P. Swaminadhan2, M.S. Bembde3 1 P.G .Student, Department of Mechanical engineering, MPGI school of Engineering,Maharashtra,India. 2 Prof.Department of Mechanical engineering, MPGI school of Engineering,Maharashtra,India. 3 Prof.Department of Mechanical engineering,Terna Engineering College,Nerul,Maharashtra,India. ---------------------------------------------------------------------***--------------------------------------------------------------------- Abstract - Powder mixed electric discharge machining (PMEDM) is a recent innovation for enhancing the capabilities of electrical discharge machining process. The objective of present study is to realize the potential of graphite powder as additive in enhancing machining capabilities of PMEDM. Taguchi methodology has been adopted to plan and analyze the experimental results. L9 Orthogonal Array has been selected to conduct experiments. Discharge current, duty factor, spark gap and concentration of fine graphite powder added into the dielectric fluid were chosen as input process variables to study performance in terms of material removal rate and surface roughness. The effect of process parameters is analyzed in this paper KEY WORDS: EDM, ANOVA, MRR, RA, PROCESS PARAMETERS, TAGUCHI METHODOLOGY,GREY RELATIONAL ANALYSIS 1.INTRODUCTION Electric discharge machining is a thermo-electric non- traditional machining process. Material is removed from the work piece through localized melting and vaporization of material. Electric sparks are generated between two electrodes when the electrodes are held at a small distance from each other in a dielectric medium and a high potential difference is applied across them. Localized regions of high temperatures are formed due to the sparks occurring between the two electrode surfaces. 1.1 PRINCIPLE OF POWDER MIXED EDM In this process, the material in powder form is mixed into the dielectric fluid either in the same tank or in a separate tank. When a voltage of 80-320 V is applied to both the electrodes, an electric field in the range 105 to 107 V/m is created. The spark gap is filled up with additiveparticles,and the gap distance between tool and the work piece increases from 25 µm to 50 µm to many times larger. The powder particles get energized and behave in a zig-zag fashion. The grains come close to each other under the sparking area and gather in clusters. Figure 1.1 Principle of PMEDM Process 1.2 EXPERIMENTAL SET UP Figure 1.2 Powder mixed Electric discharge machining (PMEDM). The various input parameters and output parameters (response variables) selected for the experimentationareas follows: 1) Input parameters 1 Discharge current (Ip) 2 Duty factor (τ)
- 2. International Research Journal of Engineering and Technology (IRJET) e-ISSN: 2395-0056 Volume: 04 Issue: 11 | Nov -2017 www.irjet.net p-ISSN: 2395-0072 © 2017, IRJET | Impact Factor value: 6.171 | ISO 9001:2008 Certified Journal | Page 1040 3 Spark gap (SG) 4 Concentration of dielectric (C) 2) Output parameters 1 Material removal rate (MRR) 2 Surface Roughness ( Ra) Graphite powder- The grain size of graphite powder is 15microns. Tool selection-The selected tool is of pure copper. The length of the tool is 80 mm and diameter of tool is 20 mm. In most of the industries for EDM, the tool used is of copper material. Since copper is cheap as compared to graphite and readily available in the market. Work piece selection- Material EN-8 is medium carbon steel has good tensile strength and usually used in applications such as shafts, studs,stressedpins,keys etc.The dimensions of work piece are70x25x6 mm. Dielectric (EDM oil) - The dielectric used in my experimentation work is EDM oil. The concentration of this dielectric is varied by adding graphite powder. This affects the material removal rate and surface finish 2. RESULTS AND DISSCUSSION. The experimental results are given below. Expt no. Discha rge curren t [Ip] Duty factor [τ] Spark gap SG Conc. dielec tric [C] MRR mm3 /min Ra µm 1 10 5 0.05 0 26.63 5.73 2 10 7 0.1 3 28.09 5.61 3 10 9 0.15 6 29.81 5.5 4 15 5 0.1 6 41.58 6.6 5 15 7 0.15 0 35.40 6.7 6 15 9 0.05 3 40.21 6.82 7 20 5 0.15 3 68.47 7.15 8 20 7 0.05 6 70.88 7.23 9 20 9 0.1 0 69.85 7.45 Table 1: Experimental results 3. REGRESSION ANALYSIS The regression equation for MRR is, MRR = - 18.9 + 4.16 Discharge current + 0.27 Duty Factor - 13.5 spark gap + 0.577 concentration The regression equation for Ra is, Ra = 4.10 + 0.166 Discharge current + 0.0242 Duty Factor - 1.43 spark gap - 0.0306 concentration 4. GREY RELATINAL ANALYSIS This approach converts a multiple- response- process optimization problem into a single response optimization situation. MeanofS/NratioforOGRGRD 201510 0 -1 -2 -3 -4 975 0.150.100.05 0 -1 -2 -3 -4 630 Discharge current(Ip) Duty factor [t] Spark gap (SG) Concentration of dielctric (C) Main Effects Plot (data means) for S/N ratio for OGRGRD Graph 1. S/N Ratio plot of overall grey relational grade With the help of the graph , optimal parametric combination has been determined. The optimal factor setting becomes as Ip3, τ1 , SG1, C3. 5. CONFIRMATORY EXPERIMENTS Optimal settings Prediction Experimental %Err or Level of factors Ip=20A, τ=5, SG=0.05mm, C=6g/l Ip=20A, τ=5, SG=0.05mm, C=6g/l MRR(mm3 /min) 68.43 69.33 1.29 Ra(µm ) 7.28 7.17 1.51 Table 2. Results of confirmatory experiment
- 3. International Research Journal of Engineering and Technology (IRJET) e-ISSN: 2395-0056 Volume: 04 Issue: 11 | Nov -2017 www.irjet.net p-ISSN: 2395-0072 © 2017, IRJET | Impact Factor value: 6.171 | ISO 9001:2008 Certified Journal | Page 1041 5. CONCLUSION The material removal of the EDM process is rather low, especially in the case of EDM where the total volume of a cavity has to be removed. If the EDM is operated at the optimum setting of electrical parametersthenthisdrawback can be minimized. While machining the material EN8, the industrialist can directly use the optimum values so that the material removal rate will be maximum and Ra value will be minimum. The common optimum values for both MRR and Ra can be easily obtained by the use of grey relational analysis method 6. REFERENCES [1] H.K.Kansal , S.Singh and Pradeep Kumar, “Effect of Silicon Powder Mixed EDM on Machining Rate of AISID2Die Steel”, Journal of ManufacturingProcessesVol.9/No.12007. [2] G. Bharath Reddy, G.Naveen Kumar and Chandrashekar, “Experimental Investigation on Process Performance of Powder Mixed Electric Discharge Machining of AISI D3 steel and EN-31 steel” International Journal of Current Engineering and Technology, India .Accepted 02 May 2014, Available online 01 June 2014, Vol.4, No.3 (June 2014). [3]Sanjeev Kumar,∗, Uma Batra,“Surface modification of die steel materials by EDM method using tungsten powder- mixed dielectric” Journal of ManufacturingProcesses (2012) 35-40. [4] Xue Bai, Qinhe Zhang,∗, Jianhua Zhang Dezheng Kong, Tingyi Yang “Machining efficiency of powder mixedneardry electrical discharge machining based on different material combinations of tool electrode and workpiece electrode”Journal of Manufacturing Processes 15 (2013). [5] F.Q. Hu, F.Y. Cao, B.Y. Song, P.J. Hou, Y. Zhang, K. Chen, J.Q surface properties of SiCp/Al composite by powder-mixed EDM www.sciencedirect.com ( 2013) 101 – 106. [6] Ryota Toshimitsua, Akira Okada,*, RyojiKitada and Yasuhiro Okamoto“ Improvement in SurfaceCharacteristics by EDM with Chromium Powder Mixed Fluid” Available on www.sciencedirect.com [7] W.S. Ghao, Q. G. Meng, Z. L. Wang “application of research on powder mixed edm in rough machining”. journal of material processing technology(129-2002).