Modeling of Wire Electrical Discharge Machining ... - IJETAE

International Journal of Emerging Technology and Advanced Engineering
Website: www.ijetae.com (ISSN 2250-2459, Volume 2, Issue 4, April 2012)
WEDM of Ti-6Al-4V. The various parameters were
selected using design of experiments method.
II. LITERATURE REVIEW
There are a number of published works that reveal the
influence of WEDM parameters on the surface roughness
of different materials. Y.S. Liao found that surface
roughness is most affected by the pulse on time [5]. The
WEDM parameters are generally classified into two groups
namely electrical and non electrical. [6]. S.S. Mahapatra
and Amar Patnaik have investigated the effect of various
parameters and found that current, pulse duration and
dielectric pressure play most significant role in surface
finish [7]. U.Esme et.al observed that increase in pulse
duration, voltage and wire speed increase the surface
roughness whereas increase in flushing pressure of
dielectric fluid decrease the surface roughness [8]. The
investigations made by J.T Hung et.al revealed that pulse
on time is one of the significant factors that influence
surface roughness [9]. The previous researchers established
that pulse duration, voltage, and dielectric pressure are the
desired combination to control the surface finish [1].
Ramakrishnan et al. described the multi objective
optimization of the WEDM process using parametric
design of Taguchi methodology [11]. Fuzhu Han et.al
found that surface roughness can be improved by
decreasing both pulse duration and discharge current [10].
Although lot of investigations were done on the influence
of various WEDM parameters on surface roughness, till
date no investigation was conducted on the influence of
pulse on time, pulse off time, voltage and dielectric
pressure on WEDM of Ti-6Al-4V using DOE. This
experimental study reveals the influence of pulse on time,
pulse off time, voltage and dielectric pressure and its
interactions on the surface roughness in WEDM of Ti-6Al-
4V alloy.
FIGURE .1 DETAILS OF WEDM SETUP.
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III. EXPERIMENTAL SET UP
The experimental set up adopted for present study is
given in figure 2. The WEDM experiments were conducted
in Electronica ultra cut s1 machine using 0.25 mm brass
wire as the tool electrode. ‗Pulse on time‘, ‗pulse off time‘,
‗voltage‘ and ‗dielectric pressure‘ are the four WEDM
parameters that were selected for investigations. In this
experimental study two level full factorial experiment is
adopted because this gives all possible combinations of
machine parameters. All other machine parameters were
kept constant during the time of experiment.
IV. EXPERIMENTAL DESIGN BASED ON DOE
A full factorial design with all factors at two levels
provides the estimation of all the required parameter
combinations. Altogether sixteen experiments and two
conformation tests were conducted. For the analysis of the
experiments 10% confidence level is used.
FIGURE.2 ELECTRONICA ULTRACUT S1 WEDM 5-AXES
ANNOVA table helped to find out the significant factors
and to establish the mathematical relationship between the
surface roughness and machining parameters.
TABLE I
MACHINING PARAMETERS AND LEVELS
Factor Parameters Level 1 Level 2
A Pulse on time (μS) 20 25
B Pluse off time (μS) 44 50
C Voltage (V) 25 30
D
Dielectric pressure
(kgf/cm 2 )
10 15