B. AISI P20 tool steel material using

 

  B. Sidda Reddy et al. 11 studied that
influence by design four factors such as current, servo control, duty cycle and
open circuit voltage over the outputs on MRR, TWR, SR and hardness on the
die-sinker EDM of machining AISI 304 SS. They had been employed DOE technique
with mixed level design and analyze for performing a minimum number of runs. They
achieved that for higher MRR, the current, servo and duty cycle should be fixed
as high levels and 95% confidence level with descending order in case of TWR
with same factors.

     

 M.M. Rahman et al. 12 experimentally found
out the machining characteristic of austenitic stainless steel 304 through
electric discharge machining. The investigation shows that with increasing
current increases the MRR and surface roughness. The TWR increases with peak current
until 150 µsec pulse on time. And from the results they were found for copper electrode
al long pulse on time no tool wear with reverse polarity.

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S.
K. Dewangan 13 investigated the effect of machining parameter settings like
pulse on time, discharge current and diameter of tool of AISI P20 tool steel
material using U-shaped copper electrode with interior flushing technique.
Experiments were conducted with the L18 orthogonal array based on the Taguchi
method. Moreover, the signal-to- noise ratios associated with the observed
values in the experiments were determined by which factor is most affected by
the Responses of Material Removal Rate (MRR), overcut (OC) and Tool Wear Rate
(TWR).

 

S.
H. Tomadi et al. 14 analyzed that effect of machining settings of tungsten
carbide on the outputs such as TWR, MRR and Surface finish. Confirmation test
performed to evaluate error between predicted values and by experimental runs
in terms of machining characteristics. They were found out copper tungsten tool
use for better surface finishing of the work piece.  They were using full factorial DOE for
optimization and found out with greater pulse off time lesser tool wear of
tungsten carbide and with current, voltage and pulse on time increment tool wear
increased.

                                                                                 
   6.

 

Sanjeev
Kumar et al 15 reviewed on the new uses of electrical discharge machining
(EDM) process, with certain prominence on the prospective of this process for
surface alteration. Above and beyond removal of work material during machining,
the fundamental nature of the process results in erosion of tool material also.
Creation of the plasma passage containing of material vapors from the eroding
work material and tool electrode; and pyrolysis of the dielectric affect the
surface composition after machining and hence, its properties. Deliberate material
transfer may be carried out under specific machining conditions by using either
composite electrodes or by a break up metallic powders in the dielectric or
both. In this review on the wonder of surface modification by electric
discharge machining and upcoming leanings of its applications.

 

B.
Bhattacharyya et al. 16 Experimented on EDM using the development of a
mathematical model based on RSM for correlating the interactive and higher
order effect on machining parameter such as peak current and pulse on time of
surface integrity of M2 Die steel machined through analysis of EDM parameters
on surface roughness, white layer thickness and surface crack density. With the
developed model the optimal combination evaluated for minimizing the surface
integrity.

     

 Puertas et al. 17 Investigated the attention
on the die-sinking EDM with an adequate selection of machining condition is the
most important aspects of the machine. They were found that the impact of the
features of intensity, pulse on period and duty cycle over cemented carbide or
hard material such as 94WC-6Co. They determine characteristics: TWR, MRR and Ra
by mathematical simulations will be achieved with the DOE method combined with
multiple regressions has been effectively applied to modelling for optimal
machining condition. When intensity or pulse times were increased, the
roughness value also increased. With tungsten carbide low values should be used
for both intensity and pulse time.

 

J.
Simao et al 18 investigated work on the surface alloying of the different
work piece on machining over EDM. In experiments powder metallurgy made tools and
use of powders suspended in dielectric liquid. Based on experimental results
the use of primary sintered electrodes made  from tungsten carbide resulted in the
formation of a uniform modified surface layer with some micro cracks  and an average thickness of up to 30 µm.

                                                                            

                                                                      
             7.

 

T.
M. ChenthilJegan et al 19 determines the assortment of machining settings
like peak Current, Pulse on time, Pulse off time in EDM intended for the
machining of AISI202 stainless steel metal. They were using of grey relational
analysis technique to optimizing the machining parameters MRR and SR is
introduced. The greatest nominal influence in addition to the order of
significance of the manageable influences to the multi performance physical characteristics
on EDM machining procedure stayed determined. The results show that Discharge
current was the main parameter affecting the MRR.

 

S.
Jai Hindus et al 20 done experimentations by way of the Box Behniken design.
The effects show that TWR and MRR are deeply affected using Pulse on time and
current (A). Cylinder-shaped copper tool ensuring a dimension of diameter of 13
mm is castoff to machining of stainless steel 316 L work piece. On MRR the
greatest weighty cause was found to be Pulse on time trailed by peak current
(A) and the smallest significant was gap voltage. The MRR increased linearly
with the increase in current (A). For tool wear the most significant factor was
current (A) followed by Pulse on time (tw) and also laterally with the increase
in voltage.

 

T.
Rajmohan et al 21 experimented using design of experiment technique under L9 orthogonal
array design and considering the effect of machining parameters of EDM such as pulse
on time, pulse off time , current and voltage on MRR in machining of AISI304
stainless steel. For optimization they had been used signal to noise ratio and
analysis of variance to analyze the effect of the parameters on MRR and also
optimize the cutting parameters.

 

M.
Kiyak and O. Cak?r 22 examined that the influences of EDM settings on surface
roughness for machining of AISI P20 tool steel. Discharge current, pulses on
time and pulse pause time are the selected parameters. They were found that
surface roughness of work piece and tool were influenced by discharge current
and pulse time with increasing values SR increased and with lower value and
higher pulse pause time a good surface finish achieved.                                                                                                                                                                                                                      

 

 

 

                                                                                    8.

 

M.
S. Reza et al 23 optimize the controlled parameters of EDM using injection
flushing type machining on multi performance characteristics using GRA method.
Parameters are optimized on different Response such as MRR, TWR and SR. For
this experiment copper tool and AISI 304 stainless steel work piece is
utilized. L18 Taguchi’s orthogonal array design planned for experiments.
Selected machine settings are Ip, Ton, polarity, voltage, dielectric liquid
pressure and machining depth have been taken.

    

Ashok
Kumar et al 24 investigated machining of EN-19 tool steel using U-shaped
tubular copper tool with internal flushing by EDM. Taguchi’s L18 OA design
utilized for all runs. They found that MRR increases when current increases
with reduction on pulse on time, TWR increases with pulse on time increment and
overcut is increases with current increment.

 

P.
Srinivasa Rao et al 25 has been developed the mathematical model for
predicting die sinking EDM of AISI 304 stainless steel work piece on response
such as TWR, MRR, Ra and HRB using fuzzy logic modeling. A regression analysis
of experimental and predicted output was performed to investigate the model.
With fuzzy rule relationship was establish through experimentation to reduce
the no. of runs.

 

 

 

 

 

 

 

 

 

 

 

 

                                                                                   
9.                                          

                                               
CHAPTER 3

 

3.1 Objective of the Work

 

ü  The objective of the work is to investigate the
effect of machining variables viz. discharge current ,pulse on time &
voltage on output performance such as MRR, TWR & SR during machining of
EN31 steel work piece in Static and Rotary EDM by using pure copper tool
material.

 

ü  In this work we also have to calculate the results
of static as well as Rotary EDM.