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 3
Sr. No.
Name of the attribute for
EDM process
Significance as per the order of its influence on
process objectives
1 Pulse time, Ta Very very critical ( rated 8 on a scale of 10)
2 Current intensity, I, Very critical ( rated 7 on a scale of 10)
3 Pulse Interval, Tb critical ( rated 6.5 on a scale of 10)
4 Polarity of the Tool electrode Significant but not critical ( rated 5 on a scale of
P(-)
10)
5 Polarity of the Tool-Piece Significant but not critical ( rated 5 on a scale of
P(+)
10)
6 Working depth, h significant ( rated 4 on a scale of 10)
From various graphs of the process variables for Electric Discharge Machining process, the interactions between
the various attributes have been analyzed as below table :
Dependency of
attributes
Table 4
Dependency on attributes
I Ta Tb P(-) P(+) h
I --- 20% 35% 25% 30% 40%
Ta 40% --- 35% --- 55% ---
Tb 35% 60% --- 50% 40% 50%
P(-) --- 30% 60% --- 60% ---
P(+) 40% --- 20% 15% --- 40%
h --- 25% --- 40% 50% ---
The combined matrix as used for the permanent calculation of the inheritance effect of the attributes and their
interdependencies is further represented in below table:
Dependency of
attributes
Table 5
Dependency on attributes
I Ta Tb P(-) P(+) h
I 0.70 0.20 0.35 0.25 0.30 0.40
Ta 0.40 0.80 0.35 --- 0.55 ---
Tb 0.35 0.60 0.65 0.50 0.40 0.50
P(-) --- 0.30 0.60 0.50 0.60 ---
P(+) 0.40 --- 0.20 0.15 0.50 0.40
h --- 0.25 --- 0.40 0.50 0.40
In order to calculate the Permanent of the Matrix [P] as shown below, the number of terms has been represented
in Microsoft EXCEL and computations have been done in EXCEL which can be easily used for the sensitivity
analysis of the attributes on the Electrical Discharge Machining process.
Table 6
I Ta Tb P(-) P(+) h
0.70 0.20 0.35 0.25 0.30 0.40
0.40 0.80 0.35 --- 0.55 ---
[P] = 0.35 0.60 0.65 0.50 0.40 0.50
--- 0.30 0.60 0.50 0.60 ---
0.40 --- 0.20 0.15 0.50 0.40
--- 0.25 --- 0.40 0.50 0.40
Since the Microsoft EXCEL worksheet is dynamic enough to explore the effect of changes in the
interdependency factor in the Matrix [P] in particular constructed for the EDM process. For the present
computation, the effect of present state of the Interdependencies of the attributes, the pictorial representation of
the computations for the Subgrouping under various groupings is shown in below table:
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