OCTOBER 19-20, 2012 - YMCA University of Science & Technology

Proceedings of the National Conference on
Trends and Advances in Mechanical Engineering,
YMCA University of Science & Technology, Faridabad, Haryana, Oct 19-20, 2012
Table 1: Levels of different process parameters
Process
Parameter
Symbol
Used
S.I Units
Range
Peak Current A Amperes 90-230
Pulse On Time B µs 115-130
Pulse Off Time C µs 48-56
Wire Tension D grams 5-10
The En31 Rectangular bar of 100mm x 20mm x 15mm is mounted on Electronic a Sprint Cut Wire EDM
machine tool and the specimens of size 15mm x 20 mm x 8 mm are cut.
Fig (2): Cut Specimens
In this phase, four process parameters viz. peak current, pulse on time, pulse off time, and wire tension were
selected as given in table(3) Experiments were conducted according to the test conditions specified by the L 9
Orthogonal Array as described.
Table (3): Response table for Surface Roughness
Expt
Run
(
A
)
P
C
(
B
)
(
C
)
T
o
n
T
o
ff
(
D
)
W
T
R
a
1
R
a
2
T
r
i
a
l
T
r
i
a
l
2
Mea
n of
Ra 1
&
Ra 2
1 1 1 1 1 1.58 1.54 1.56
2 1 2 2 2 1.76 1.75 1.755
3 1 3 3 3 3.43 3.42 3.425
4 2 1 2 3 1.51 1.51 1.51
5 2 2 3 1 3.69 3.67 3.68
6 2 3 1 2 3.02 3.01 3.015
7 3 1 3 2 4.48 4.41 4.445
8 3 2 1 3 5.00 4.48 4.74
9 3 3 2 1 3.83 3.82 3.825
Avg. of Surface
Roughness=3.106
6. Results & Discussions
6.1 Normal probability plot for Surface Roughness
The normal probability plot is a graphical technique for assessing whether or not a data set is approximately
normally distributed. The points on this plot form a nearly linear pattern, which indicates that the normal
distribution is a good model for this data set. The normal probability plot showed the set of value of response
variables are very close to median of set of values and not deviate from mid value.
Fig: (3) Normal Probability plot for Surface Roughness
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