1. International Journal of Advanced Research in Engineering and Technology (IJARET), ISSN
0976 – 6480(Print), ISSN 0976 – 6499(Online) Volume 4, Issue 4, May – June (2013), © IAEME
191
APPLICATION OF TAGUCHI METHOD IN THE OPTIMIZATION OF
BORING PARAMETERS
Ajeet Kumar rai*, Shalini yadav, Richa Dubey and Vivek Sachan
Mechanical Engineering Department
Sam Higginbottom Institute of Agriculture, Technology and Sciences, Allahabad-211004,
India
ABSTRACT
In the present study, Taguchi method is applied to find optimum process parameters
in the boring operation of a cast iron work piece. A L27 orthogonal array, signal-to-noise ratio
and analysis of variances are applied to study the performance characteristics of machining
parameters (cutting speed, feed rate and depth of cut) with consideration of surface finish.
Experimental results reveal that among the cutting parameters, the depth of cut is most
significant machining parameter for surface roughness followed by feed rate and cutting
speed in the specified test range.
Keywords:, Optimization, Taguchi method, S/N ratio, Boring operation
INTRODUCTION
Taguchi parameter design offers a systematic approach for optimization of various
parameters with regards to performance, quality and cost. And it is important in a sense to
meet the challenge coming before the manufacturers, which are to increase the production
rate, reducing operating cost and enhancing the quality of production. Taguchi primarily
recommends experimental design as a tool to make products more robust- to make them less
sensitive to noise factors. He views experimental design as a tool for reducing the effect of
variation on product and process quality characteristics [1]. The complete procedure in
Taguchi design method can be divided into three stages: system design, parameter design and
tolerance design. Of the three design stages, the second stage- the parameter design –is
considered to be the most important stage [2]. This stage of Taguchi parameter design
requires that the factors affecting quality characteristics in the manufacturing process have to
be determined. The major goal of this stage is to identify the optimal cutting conductions that
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ISSN 0976 - 6480 (Print)
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2. International Journal of Advanced Research in Engineering and Technology (IJARET), ISSN
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yield the lowest surface roughness value. Few steps to be followed in the Taguchi parameter
design are: selecting the proper orthogonal array (OA) according to the numbers of
controllable factors, running experiments based on the OA, analyzing data, Identifying the
optimum condition, and conducting confirmation runs with the optimal levels of all the
parameters. Taguchi method is used by several researchers to carry out their studies in
various machining operations like turning, end milling, drilling etc.
Yang et al [3] used the Taguchi parameter design in order to identify optimum surface
roughness performance on an aluminum material with cutting parameters of depth of cut,
cutting speed, feed rate and tool diameter. It was found that tool diameter is not a significant
cutting factor affecting the surface roughness. Bagci et al [4] used the Taguchi method to
explore the effects of drilling parameters on the twist drill bit temperature for a design
optimization of cutting parameters. Zhang et al [5] performed a study of the Taguchi Design
application to optimize surface quality in a CNC face milling operation. Taguchi design was
successful in optimizing milling parameters for surface roughness. Nalbant et al. [6] used
Taguchi method to find optimum cutting parameters for surface roughness in turning of AISI
1030 carbon steel bars using TiN coated tools. Three cutting parameters namely, insert
radius, feed rate, and depth of cut are optimized with considerations of surface roughness. In
turning, use of greater insert radius, low feed rate and low depth of cut are recommended to
obtain better surface roughness for the specific test range. Ghani et al. [7] applied Taguchi
method to find optimum cutting parameters for surface roughness and cutting force in end
milling when machining hardened steel AISI H13 with TiN coated P10 carbide insert tool
under semi-finishing and finishing conditions of high speed cutting. The milling parameters
evaluated is cutting speed, feed rate, and depth of cut. In end milling, use of high cutting
speed, low feed rate and low depth of cut are recommended to obtain better surface roughness
and low cutting force. Kurt et al [6] employed the Taguchi method in the optimization of
cutting parameters for surface finish and hole diameter accuracy in dry drilling processes.
The validity of the Taguchi approach to process optimization was well established.
From the above stated literature review, it becomes clear that the Taguchi Design method has
been widely applied with great success for optimizing industrial/production processes.
Keeping this perspective the present work has been taken with the objective to investigate the
effects of different boring parameters on surface roughness, and is to determine the optimal
boring parameters using the Taguchi technique.
EXPERIMENTAL DESIGN
Table1 shows three factors and three levels used in the experiment. For selecting
appropriate arrays, degree of freedom of array is calculated. There are six degrees of freedom
owing to three machining parameters, so Taguchi based L27 orthogonal array is selected
(Table 2). Accordingly 27 experiments were carried out to study the effect of machining
input parameters. Each experiment was repeated three times in order to reduce experimental
errors.
Table 1: Level of process parameters
Symbol Factors Level 1 Level 2 Level 3
A Cutting Speed (m/min) 80 100 120
B Feed (mm/rev.) 0.05 0.1 0.15
C Depth of cut (mm) 0.3 0.4 0.5

3. International Journal of Advanced Research in Engineering and Technology (IJARET), ISSN
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Table 2: Taguchi’s L27 orthogonal array
Factor
Standard order A B C
1 80 0.05 0.3
2 80 0.05 0.4
3 80 0.05 0.5
4 80 0.1 0.3
5 80 0.1 0.4
6 80 0.1 0.5
7 80 0.15 0.3
8 80 0.15 0.4
9 80 0.15 0.5
10 100 0.05 0.3
11 100 0.05 0.4
12 100 0.05 0.5
13 100 0.1 0.3
14 100 0.1 0.4
15 100 0.1 0.5
16 100 0.15 0.3
17 100 0.15 0.4
18 100 0.15 0.5
19 120 0.05 0.3
20 120 0.05 0.4
21 120 0.05 0.5
22 120 0.1 0.3
23 120 0.1 0.4
24 120 0.1 0.5
25 120 0.15 0.3
26 120 0.15 0.4
27 120 0.15 0.5
RESULTS AND DISCUSSION
The Taguchi method employs a generic signal- to–noise (S/N) ratio to quantify the
present variation. These S/N ratios are meant to be used as measures of the effect of noise
factors on performance characteristics. S/N ratios take into account both amount of variability
in the response data and closeness of the average response to target. There are several S/N
ratios available depending on type of characteristics: smaller is better, nominal is better and
larger is better. Twenty-seven experiments were performed using the design parameter

4. International Journal of Advanced Research in Engineering and Technology (IJARET), ISSN
0976 – 6480(Print), ISSN 0976 – 6499(Online) Volume 4, Issue 4, May – June (2013), © IAEME
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combinations in the specified orthogonal array table. Nine specimens were fabricated for
each of the parameter combinations. The complete response table for these data appears in
Table 3. In order to estimate the effect of factor A (Cutting Speed) on average value of
response variables, were summed together nine observed response at level 1 of factor A.
Then the sum was divided by nine to obtain the average response. Average responses at level
2 and level 3 were obtained in the similar manner. The estimated effects are presented
graphically in fig. 2. The range of average responses over the three levels of each
experimental factor is:
For Cutting speed = 72.5
For Feed rate = 41.6666
For Depth of cut = 31.3889
In particular, factor A, B and C should be set at level 2, level 3 and level 1 respectively.
Figure 2: Estimated factor effects
The sample standard deviation is generally accepted measure of variability in
statistical data analysis and experimental design. This statistics is somewhat more difficult to
calculate than the sample range, but it has desirable properties which make its use worth the
added effort.
The standard deviation was calculated for each tube in five steps. First, y was
subtracted from each measurement in the sample (sample mean), then the square differences
obtained prior were calculated. Next, the squared obtained differences were and was divided
the sum by the sample size minus one (s2
). Finally obtain the square root of s2
. The sample
variance is written as
s2
= ∑(y-y)2
/(n-1) (1)
s = √s2
(2)
0
50
100
150
200
250
300
350
A1 A2 A3 B1 B2 B3 C1 C2 C3
Average
Level of factor

5. International Journal of Advanced Research in Engineering and Technology (IJARET), ISSN
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Table 3: Experimental data sample statistics
Experiment
Number
Observed response
values of Surface
Roughness (µm)
Mean Standard
Deviation
Log of
S.D.
S/N Ratio
1 10 15 12.5 3.5355 0.5484 -21.9382
2 280 300 290 14.1421 1.1505 -49.2479
3 340 360 350 14.1421 1.1505 -50.8813
4 400 425 412.5 17.6776 1.2474 -52.3084
5 450 425 437.5 17.6776 1.2474 -52.8195
6 440 415 427.5 17.6776 1.2474 -52.6187
7 345 375 360 21.2132 1.3266 -51.1260
8 290 320 305 21.2132 1.3266 -49.685
9 300 335 317.5 24.7487 1.3935 -50.0348
10 320 340 330 14.1421 1.1505 -50.3702
11 335 350 342.5 10.6066 1.0255 -50.6932
12 300 315 307.5 10.6066 1.0255 -49.756
13 230 245 237.5 10.6066 1.0255 -47.5132
14 145 165 155 14.1421 1.1505 -43.8066
15 250 225 237.5 17.6776 1.2474 -47.5132
16 240 220 230 14.1421 1.1505 -47.2345
17 280 305 292.5 17.6776 1.2474 -49.3225
18 115 140 127.5 17.6776 1.2474 -42.1102
19 275 285 280 7.0710 0.8494 -48.9431
20 210 225 217.5 10.6066 1.0255 -46.7491
21 290 300 295 7.0710 0.8494 -49.3964
22 250 280 265 21.2132 1.3266 -48.4649
23 290 315 302.52 17.6776 1.2474 -49.6145
24 275 250 262.5 17.6776 1.2474 -48.3825
25 230 210 220 14.1421 1.1505 -46.8484
26 275 300 287.5 17.6776 1.2474 -49.1727
27 215 230 222.5 10.6066 1.0255 -46.9466
The estimated log s effects from Table 3 are plotted in Fig.3.In order to minimize the
variability the following optimum results were obtained.
Factor A, Cutting Speed at level 3
Factor B, feed rate at level 1
Factor C, Depth of cut at level 1

6. International Journal of Advanced Research in Engineering and Technology (IJARET), ISSN
0976 – 6480(Print), ISSN 0976 – 6499(Online) Volume 4, Issue 4, May – June (2013), © IAEME
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Figure 3: Estimated factor effects on log(s)
In this work, the minimum surface roughness is the indication of better performance.
Therefore, the smaller-is-better for the surface roughness was selected for obtaining optimum
result. The following S/N ratios for the lower-is-better case could be calculated:S/NLB = −10
Log (
ଵ
௥
∑ y௥
௜ୀଵ i
2
)
Fig 4 photograph showing experimentation
0
0.2
0.4
0.6
0.8
1
1.2
1.4
A1 A2 A3 B1 B2 B3 C1 C2 C3
Log(s)
Level of Factor

7. International Journal of Advanced Research in Engineering and Technology (IJARET), ISSN
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Figure 4: Plot of factor effects on S/N Ratio
Table 4: Overall mean S/N Ratio
Level Average S/N Ratio by factor level Overall mean
S/N RatioA B C
1 -47.8510 -46.4417 -46.0829 -47.9072
2 -47.5910 -49.2268 -49.0123
3 -48.2798 -48.0534 -48.6266
In order to maximize the S/N ratio the following assignments were done: factor A
(Cutting speed) – level 2, factor B (Feed rate) – level 1, factor C (Depth of cut) – level 1.
Figure 4 shows that factor C have a strong effect on S/N ratio response. Factor B is the next
most significant. The above analyses of table 3 and table 4 are summarized in table 5. In that
table the levels of key factors which are optimizing the response are listed. Some significant
levels are shown in fig. 2, 3 and 4. Keep in mind that the objective is to minimize the
response average, minimize log s, and maximize the S/N Ratio.
Table 5. Summary of analyses of factor effects
Level which was optimized
Factor y Log s S/N Ratio
A 2 3 2
B 3 1 1
C 1 1 1
In this study factor A and B were dominant. For parameter C, reducing log s will have little
effect on the performance than the S/N ratio. So level 1 is optimized. The final optimized
values are:-
1) Cutting speed: - Level 2 – 100 m/min.
2) Feed rate: - Level 1 - 0.15 mm/rev.
3) Depth of cut: - Level 1 - 0.3 mm.
-49.5
-49
-48.5
-48
-47.5
-47
-46.5
-46
-45.5
-45
-44.5
A1 A2 A3 B1 B2 B3 C1 C2 C3
S/NRatio
Level of Factor

8. International Journal of Advanced Research in Engineering and Technology (IJARET), ISSN
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CONCLUSIONS
In this study, the Taguchi optimization method was applied to find the optimal
process parameters, which minimizes the surface roughness during the boring of cast iron. A
Taguchi orthogonal array, the signal to noise(S/N) ratio and the analysis of variance
(ANOVA), were used for the optimization of cutting parameters. Results show that depth of
cut will have great influence on the surface roughness followed by feed and cutting speed.
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[3]Yang , J. L., Chen J.C. (2001) A systematic approach for identifying optimum surface
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[4] Bagci E., Ozcelik B. (2006) Analysis of temperature changes on the twist drill under
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[6] Nalbant, M.; Gokkaya, H.; and Sur, G. (2007). Application of Taguchi method in the
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[7] Ghani, J.A.; Chodhury, I.A.; and Hassan, H.H. (2004). Application of Taguchi method in
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APPENDIX
Fig A photograph showing machined parts