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
Main Effects Plot for SN ratios (SR)
Data Means
Polarity
Electrode ty pe
Peak C urrent
-8
-10
-12
Mean of SN ratios
-8
-10
-12
-8
-10
-12
-V e
+v e
copper cry ogenic 0.5 3.0 6.0
Ton Time Duty C y cle Gap V olt.
50 100 150 0.7 0.8 0.9 40 60
80
Retarct distance
C oncentration
1
2
3
0
6
12
Signal-to-noise: Smaller is better
Fig.2 Main Effect plot for S/N ratios for SR
Table 2 Response Table for Signal to Noise Ratios
From main effect plot Fig.2 it is observed that polarity, peak current, pulse on time retract distance significantly
Level
Polarity
Electrode
B
Peak
current
C
Pulse on
time
D
Duty
cycle
E
Gap
voltage
F
Retract
distance
G
Concentration
of powder
H
A
1 -8.992 -10.511 -6.876 -8.069 -10.063 -10.236 -9.095 -9.972
2 -11.541 -10.022 -10.816 -10.197 -10.852 -9.467 -11.014 -9.891
3 -13.108 -12.535 -9.885 -11.097 -10.691 -10.938
Delta 2.549 0.489 6.232 4.466 0.967 1.630 1.920 1.047
Rank 3 8 1 2 7 5 4 6
effect the surface roughness as these are having steeper slopes in main effect plots. Although slope of effect of
types of electrodes and concentration of fine abrasives aluminium powder are not steep, still these affect the
desired objective in positive manner. Positive polarity, higher peak current, higher pulse on time contribute more
spark energy leading to deeper and wider craters on the machined surfaces, thereby contributing for higher SR.
whereas uniformly distributed fine abrasive powders particles under sparking area results in distributed sparking
energy give more sparks and shallow craters on the surface. Response for Signals to Noise ratios at different
levels are presented in Table 2. Higher the delta value in response table more the effect of parameters on the
desired objective. Rank gives the relative importance of selected parameters on SR. Main effect plots suggest
that negative electrode polarity , cryogenically treated copper electrode , 0.5 peak current , 50 µs pulse on time ,
0.9 duty cycle 60 V gap voltage, 1mm retract distance and 6g/l of fine aluminium abrasive powder are best
parametric setting for minimum SR. At these settings confirmation experiments were performed and 6.5%
improvement was observed in SR.Provide a space of 60 pts before the title of the paper. It may be created using
“Format – Paragraph – Indent and Spacing – Spacing: Before 60 pt” option.
4. Conclusions
From present investigations following conclusions are drawn.
1) AEDM is possible option with cryogenically treated copper electrode on Inconel 718.
2) Polarity, peak current and pulse on time effect surface roughness drastically.
3) Cryogenically treated copper electrode and concentration of fine aluminium abrasive powder particles
effects the SR in positive manner and enhance SR appreciably.
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