Comparison Study of Optimization of Surface Roughness Parameters in Turning En1a Steel on a Cnc Lathe with Coolant and Without Coolant

International Research Journal of Engineering and Technology (IRJET) e-ISSN: 2395 -0056
Volume: 04 Issue: 06 | June -2017 www.irjet.net p-ISSN: 2395-0072
© 2017, IRJET | Impact Factor value: 5.181 | ISO 9001:2008 Certified Journal | Page 1977
COMPARISON STUDY OF OPTIMIZATION OF SURFACE ROUGHNESS
PARAMETERS IN TURNING EN1A STEEL ON A CNC LATHE WITH
COOLANT AND WITHOUT COOLANT
Girish Tilak1
1GirishTilak Assistant Professor, Department of Automobile Engineering, NewHorizon College of Engineering,
Karnataka, India
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Abstract - This paper presents the comparison study optimization of surface roughness parameters in turning EN1A steel on a
CNC lathe with coolant and without coolant. The optimization of machining processes is essential for the achievement of high
responsiveness of production, which provides a preliminary basis for survival in today’s dynamic market conditions. The
quantitative determination of Surface Roughness is of vital importance in the field of precision engineering. Machinability can be
based on the measure of Surface Roughness. Surface Roughness dependsonthefactorssuchasSpeed, FeedandDepthofCut. Inthis
work, the Taguchi methods, a powerful statistical tool to design of experiments for quality, is used to find the optimal cutting
parameters for turning operations. Analysis of Variance has been used to determine the influencing parameters on the output
responses. Using Taguchi technique, we have reduced number of experiments from 27 to 9 there by the total cost of the project is
reduced by 66.66%. The results obtained are encouraging and the concluding remarks are helpful for the manufacturing
industries.
Key Words: surface roughness, Taguchi method, with coolant, parameters.
1.INTRODUCTION
The machinability of metal is defined as the ease with which a given material may be machined with a specific cutting tool. In
other words the most machinable metal is one which will permit thefastestremoval ofthelargestamountofmaterial percutof
a tool with satisfactory finish. The operational characteristics of a cutting tool are generally described by its machinability
which has 3 main aspects, tool life, surface finish and power required to cut. The quantitative determination of Surface
Roughness is of vital importance in the field of precision engineering. Machinability can be based on the measure of Surface
Roughness. Surface Roughness depends on the factors such as Speed, Feed and Depth of Cut. Other factors includecuttingtool
material, cutting tool geometry, machine condition, work piecematerial,cuttingtool clampinganddependonoperationcarried
out. The presence of coolant affects the Surface Roughness. Therefore an attempt has been made to conduct experimental
investigation to optimize the Surface Roughness parameters in turning of EN1A steel on CNC lathe.
2. EXPERIMENTATION
Optimization of Machining Parameters (3 factors and 3 level analyses) and studies on Surface Roughness,MRRandMachining
Time using TNMG 16 04 08 with and without Coolant in CNC lathe (ACE) using L9:

L9 Orthogonal Array with Observations with Coolant.
Tria
l No
Turning Parameter Output Responses
A
Cuttin
g
Speed
(rpm)
B
Feed
(mm/
rev)
C
Depth
Of Cut
(mm)
Surface
Roughn
ess,
Ra
(µm)
Weight of
specimen
Before
Turning
(gm)
Weight of
specimen
After Turning
(gm)
Machini
ng
Time
(actual)
, t
(sec)
Machining
Time
(theoretica
l), t
(sec)
MRR(a)
(mm3/min)
MRR(t)
(mm3/min)
1 1000 0.1 0.2 3.19 197.301 182.706 70 58 2790.34 1200
2 1000 0.2 0.4 4.19 197.301 181.298 99 72 7474.44 7500
3 1000 0.3 0.6 4.29 197.301 178.660 94 70 14590.11 16800
4 2000 0.1 0.4 3.67 197.301 180.792 85 62 7890.48 7400
5 2000 0.2 0.6 3.79 197.301 178.520 19 26 18650 22600
6 2000 0.3 0.2 3.85 197.301 184.191 14 21 11930.35 11800
7 3000 0.1 0.6 2.84 197.301 177.867 19 28 14758.24 17200
8 3000 0.2 0.2 3.71 197.301 183.532 13 22 11776.78 12800
9 3000 0.3 0.4 3.82 197.301 181.373 11 19 22992.85 33400

3. RESULTS AND DISCUSSION
In this experiment turning operation was done on the work piece i.e., EN 1A Steel on a CNC lathe. UncoatedCarbideInsertwas
used for turning. 3 factors were selected i.e., Speed (rpm), Feed (mm/rev) and Depth of Cut (mm) at 3 levels and coolant was
not used. Surface Roughness was measured using Profilometer (Talysurf) and the readings are tabulated in Table.
3.1 Analysis of Variance for Surface Roughness:
Source
DF Seg SS Adj SS Adj MS F P RANK
Contribution
Speed (rpm) 2 1.7727 1.7727 0.8864 1.85 0.351 2 19.64%
Feed (mm/rev) 2 6.2228 6.2228 3.1114 6.50 0.133 1 69.00%
Depth of Cut (mm) 2 1.0280 1.0280 0.5140 1.07 0.482 3 11.36%
Error 2 0.9577 0.9577 0.4788
Total 8 9.9812 9.42 100%
Without coolant
Sou
rce
DF Seg SS Adj SS Adj MS F P RANK
Cont
ribut
ion
Speed (m/
min)
2 2.412 2.412 1.2061 1.57 0.388 2
18.98%
Feed (mm/
rev)
2 8.686 8.686 4.3430 5.67 0.150 1
68.56%
Depth
of
Cut (mm)
2 1.573 1.573 0.7865 1.03 0.493 3
12.46%
Error 2 1.532 1.532 0.7662
Total 8 14.204 8.27 100%
With coolant
3.2 Response Table of Signal to Noise Ratios for Surface Roughness:
Levels
Speed
(rpm)
Feed
(mm/rev)
Depth of Cut
(mm)
1 -11.72 -10.15 -11.06
2 -11.53 -11.80 -11.79
3 -10.70 -12.00 -11.10
Delta 1.02 1.85 0.74
Rank 2 1 3
Without coolant.
Levels
Speed
(rpm)
Feed
(mm/rev)
Depth of Cut
(mm)
1 -10.769 -8.951 -10.012
2 -10.637 -10.972 -10.929
3 -9.611 -11.093 -10.075
Delta 1.158 2.142 0.917
Rank 2 1 3
With coolant.

3.3 Graph showing the Main Effects Plot for S/N ratios of Ra(without coolant):
MeanofSNratios
300020001000
-10.0
-10.5
-11.0
-11.5
-12.0
0.30.20.1
0.60.40.2
-10.0
-10.5
-11.0
-11.5
-12.0
Speed (rpm) Feed (mm/rev)
DOC (mm)
Main Effects Plot (data means) for SN ratios
Signal-to-noise: Smaller is better
Figure 5: S/N ratio values for Surface Roughness
MeanofMeans
300020001000
4.0
3.8
3.6
3.4
3.2
0.30.20.1
0.60.40.2
4.0
3.8
3.6
3.4
3.2
DOC (mm)
Main Effects Plot (data means) for Means
Figure 6: Mean values for Surface Roughness
Highest S/N ratio gives optimum machining parameter. Hence from Figure 5 and Figure 6 it can be observed that optimum
values of machining parameters to get minimumSurface RoughnessareSpeed(3000rpm),Feed(0.1mm/rev)and DepthofCut
(0.2mm).
Confirmation Test: Turning was conductedatoptimumcuttingparametersi.e.,Speed 3000rpm,feed0.1mm/revandDepthof
Cut 0.2mm and found that Surface Roughness as 1.94 µm.
Graph Showing the Main Effects Plot for S/N Ratios of Ra(with coolant):
MeanofSNratios
300020001000
-9.0
-9.5
-10.0
-10.5
-11.0
0.30.20.1
0.60.40.2
-9.0
-9.5
-10.0
-10.5
-11.0
DOC (mm)
Main Effects Plot (data means) for SN ratios
Signal-to-noise: Smaller is better
Figure 5: S/N ratio values for Surface Roughness

MeanofMeans
300020001000
3.6
3.4
3.2
3.0
2.8
0.30.20.1
0.60.40.2
3.6
3.4
3.2
3.0
2.8
DOC (mm)
Main Effects Plot (data means) for Means
Figure 6: Mean values for Surface Roughness
Highest S/N ratio gives optimum machining parameter. Hence from Figure 5 and Figure 6 it can be observed that optimum
values of machining parameters to get minimumSurface RoughnessareSpeed(3000rpm),Feed(0.1mm/rev)and DepthofCut
(0.2mm).
Confirmation Test: Turning was conductedatoptimumcuttingparametersi.e.,Speed 3000rpm,feed0.1mm/revandDepthof
Cut 0.2mm and found that Surface Roughness as 1.37 µm.
3.4 To Study the Comparison of Actual And Theoretical Values of MRR(without coolant):
Figure 7: shows the comparison of Actual and Theoretical values of MRR
From Figure 7 it can be seen that for all the trials of this experiment, Theoretical value of Material Removal Rate is more
compared to Actual values of Material Removal Rate. Further it can be observed that Material Removal RateisMaximumwhen
the values of Speed, Feed and Depth of Cut are at maximum levels i.e., 3000 rpm, 0.3 mm/rev and 0.4 mm respectively. Also it
can be observed that Material Removal Rate is Minimum when the values of Speed, Feed and Depth of Cut are at minimum
levels i.e., 1000 rpm, 0.1 mm/rev and 0.2 mm respectively.
To Study the Comparison of Actual And Theoretical Values of MRR(with coolant):
Figure 7: shows the comparison of Actual and Theoretical values of MRR
From Figure 7. it can be seen that for all the trials of this Experiment, Theoretical value of Material Removal Rate is more
compared to Actual values of Material Removal Rate. Further it can be observed that Material Removal RateisMaximumwhen

the values of Speed, Feed and Depth of Cut are at maximum levels i.e., 3000 rpm, 0.3 mm/rev and 0.4 mm respectively. Also it
can be observed that Material Removal Rate is Minimum when the values of Speed, Feed and Depth of Cut are at minimum
levels i.e., 1000 rpm, 0.1 mm/rev and 0.2 mm respectively.
4. CONCLUSION:
Following is the summary drawn based on the experiment conducted on EN 1A Steel alloy during turning operation with
Uncoated Carbide Inserts without coolant.
1. Regression Model has been developed for Surface Roughness without coolant relatingSpeed,FeedandDepthofCut to
predict the value of the surface roughness.
2. The Analysis of Variance was performed to identify the influence of Machining Input parameters considered were
Speed, Feed and Depth of Cut on the output Responses Surface Roughness using MINITAB software. Based on the
Analysis of Variance the input parameters that are influencing the Output parameter Surface Roughness in their
decreasing order are Feed, Speed and Depth of Cut.
3. Feed has the highest contribution of 69% followed by Speed 19.64% and Depth of Cut 11.36%.
4. The optimum values of machining parameters to get Optimum Surface Roughness are Speed of 3000 rpm, Feed of
0.1mm/rev and Depth of Cut of 0.2mm. Surface Roughness is found that is 1.94 µm. And averageSurfaceRoughness is
found to be 3.70 µm.
5. The Material Removal Rate is Maximum i.e., 22992.85 mm3/min when the values of Speed, Feed and Depth of Cut are
3000 rpm, 0.3 mm/rev and 0.4mm respectively. And Machining Time is 11 sec i.e., Minimum at this level.
6. The Material Removal Rate is Minimum i.e., 2790.34 mm3/min when the values of Speed, Feed and Depth of Cut are
1000 rpm, 0.1 mm/rev and 0.2 mm respectively. And Machining Time is 70 sec i.e., 1.5 times the Average at thislevel.
7. The average Material Removal Rate is 12540.06 mm3/min.
Following is the summary drawn based on the experiment conducted on EN 1A Steel alloy during Turning operation with
Uncoated Carbide Inserts with Coolant.
1. Regression Model has been developed for Surface Roughness without coolant relatingSpeed,FeedandDepthofCut to
predict the value of the surface roughness.
2. The Analysis of Variance was performed to identify the influence of Machining Input parameters considered were
Speed, Feed and Depth of Cut on the output Responses Surface Roughness using MINITAB software. Based on the
Analysis of Variance the input parameters that are influencing the Output parameter Surface Roughness in their
decreasing order are Feed, Speed and Depth of Cut.
3. Feed has the highest contribution of 68.54% followed by Speed 18.98% and Depth of Cut 12.46%.
4. The optimum values of machining parameters to get Optimum Surface Roughness are Speed of 3000 rpm, Feed of
0.1mm/rev and Depth of Cut of 0.2mm.Surface Roughness is found that is 1.37 µm. And average SurfaceRoughnessis
found to be 3.32 µm.
5. Improvement of Surface Roughness by 29.34% at the optimum values and by 10.27% at the average after using the
coolant
6. The Material Removal Rate is Maximum i.e., 23214.28 mm3/min when the values of Speed, Feed and Depth of Cut are
3000 rpm, 0.3 mm/rev and 0.4mm respectively. And Machining Time is 11 sec i.e., Minimum at this level.
7. The Material Removal Rate is Minimum i.e., 2624.49 mm3/min when the values of Speed, Feed and Depth of Cut are
1000 rpm, 0.1 mm/rev and 0.2 mm respectively. And Machining Time is 49 sec i.e., Maximum at this level.
8. The average Material Removal Rate is 12729.57 mm3/min after using the coolant. Improvement of Material Removal
Rate by 1.48% at the average.
ACKNOWLEDGEMENT
I wish to express my sincere gratitude to my parents, family members, friends, colleagues, students. I thank to managementof
NHCE for the endless support. Special thanks to Mr. Salman Khan for his kind hearted behavior as person himself and for his
attitude for being human which has inspired me throughout my life.Above all, to the Great Almighty, the author of knowledge
and wisdom, for his courtless love.

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BIOGRAPHIES
GirishTilak Assistant Professor
working in the Department of
Automobile Engineering in NHCE
Bangalore. I’m interested in the
field of Manufacturing Science

Comparison Study of Optimization of Surface Roughness Parameters in Turning En1a Steel on a Cnc Lathe with Coolant and Without Coolant

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Comparison Study of Optimization of Surface Roughness Parameters in Turning En1a Steel on a Cnc Lathe with Coolant and Without Coolant