The document discusses electrochemical machining of stainless steel SS 202. It investigates how the material removal rate is affected by three factors in the electrochemical machining process: 1) the power supply, 2) the distance between the anode and cathode, and 3) the depth of immersion. Experiments were conducted where the voltage, immersion depth, and electrode distance were varied while measuring the resulting material removal rate. The results showed that the material removal rate decreased with increasing immersion depth but increased with increasing electrode distance and voltage.

1. ELECTROCHEMICAL MACHINING OF
SS 202
Bharanidharan1
,Jhonprabhu2
Department of Mechanical Engineering
M.Kumarasamy college of Engineering, Karur -639 113
Email: bharanidharan1021@gmail.com, bharanivijay11@gmail.com
ABSTRACT
The aim of this project is to study
the material removal rate in an
electrochemical machining process
of SS 202 material. When the
electrodes are immerged in the
electrolyte the electrons are
removed from the anode and
deposited in the electrolytic tank.
After taken the first reading the
electrode immerged in the
electrolyte again with high distance.
So the electrons are removed from
the anode for the given distance.
The electrode distance also varied.
When the immersion depth is
increased the material removal rate
Decreased and then the electrode
distance is increased the material
removal rate increased. The voltage
increased means the material
removal rate is increased. So the
material removal rate is dependent
upon the voltage immerged
distance.
Results indicated that material
removal rate is dependent on three
factors
1) Power supply,
2) Distance between anode and
cathode,
3) Depth of immersion.
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2. CHAPTER-1
INTRODUCTION
IMPORTANCE OF ECM:
In electro chemical machining
process there is no residual stress
induced in the work piece. But other
machining process like lathe the
residual stress are induced. There is
no tool wear; machining is done at
low voltages compared to other
processes with high metal removal
rate; small dimensions can be
controlled; hard conductive materials
can be machined into complicated
profiles; work piece structure suffer
no thermal damages; suitable for mass
production work and low labour
requirements.
CHAPTER-2
LITERATURE REVIEW
M.H. Abdel-Aziz - May 2014:
The effect of electrode oscillation on
the rate of diffusion-controlled anodic
processes such as electro polishing
and electrochemical machining was
studied by measuring the limiting
current of the anodic dissolution of a
vertical copper cylinder in phosphoric
acid. Parameters studied were
frequency and amplitude of
oscillation, and phosphoric acid
concentration. Within the present
range of conditions, electrode
oscillation was found to enhance the
rate of anodic dissolution up to a
maximum of 7.17 depending on the
operating conditions. The mass
transfer coefficient of the dissolution
of the oscillating vertical copper
cylinder in H3PO4 was correlated to
other parameters by the equation:
Sh=0.316Sc0.33Rev0.64.The
importance of the present study for
increasing the rate of production in
electro polishing and electrochemical
machining, and other
electrometallurgical processes limited
by anode passivity due to salt
formation such as electro refining of
metals was highlighted.
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3. F. Klocke – 2013:
In order to increase the efficiency
of jet engines hard to machine
nickel-based and titanium-based
alloys are in common use for
aero engine components such as
blades and blisks (blade
integrated disks). Here
Electrochemical Machining
(ECM) is a promising alternative
to milling operations. Due to lack
of appropriate process modeling
capabilities beforehand still
knowledge based and a cost
intensive cathode design process
is passed through.
Therefore this paper presents a
multi-physical approach for
modeling the ECM material
removal process by coupling all
relevant conservation equations.
The resulting simulation model is
validated by the example of a
compressor blade. Finally a new
approach for an inverted cathode
design process is introduced and
discussed.
M. Burger - January 2012:
Nickel-base single-crystalline
materials such as LEK94 possess
excellent thermo-mechanical
properties at high temperatures
combined with low density compared
to similar single-crystalline materials
used in aero engines. Since the
components of aero engines have to
fulfill demanding safety standards, the
machining of the material used for
these components must result in a
high geometrical accuracy in addition
to a high surface quality. These
requirements can be achieved by
electrochemical and precise
electrochemical machining
(ECM/PECM). In order to identify
proper machining parameters for
PECM the electrochemical
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4. characteristics dependent on the
microstructure and the chemical
homogeneity of LEK94 are
investigated in this contribution. The
current density was found to be the
major machining parameter affecting
the surface quality of LEK94. It
depends on the size of the machining-
gap, the applied voltage and the
electrical conductivity of the
electrolyte used. Low current
densities yield inhomogeneous
electrochemical dissolution of
different micro structural areas of the
material and lead to rough surfaces.
High surface qualities can be achieved
by employing homogenous
electrochemical dissolution, which
can be undertaken by high current
densities. Furthermore, a special
electrode was developed for the
improvement of the quality of side-
gap machined surfaces.
CHAPTER-3
ELECTROCHEMICAL
MACHINING PROCESS:
fig.3.1
In ECM, the principles of electrolysis
are used to remove metal from the
work pieces. FARADAY’S LAWS of
electrolysis may be stated as: “the
weight of substance produced during
electrolysis is directly proportional to
the current which passes the length of
time of the electrolysis process and
the equivalent weight of the material,
which is deposited”. The work piece
is made the anode and the tool is
made the cathode. The electrolyte is
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5. filled in the beaker. As the power
supply is switched on and the current
flows through the circuit, electrons
are removed from the surface atoms
of work piece. These can get
deposited in the electrolytic tank.
After applying current the electron
will move towards the work piece
and also the settles down in the
bottom. The tool is fed towards the
work piece automatically at constant
velocity to control the gap between
the electrodes the tool face has the
reverse shape of the desired work
piece. The sides of the tool are
insulated to concentrate the metal
removal action
at the bottom face of the tool. The
dissolved metal is carried away in the
flowing electrolyte. The positive
supply is supplied to Stainless Steel
202 material.
3.1 Experimental setup:
fig.3.1A
COMPONENTS:
Power supply
Work piece
Tool
Electrolyte and Electrolytic tank
3.2 POWER SUPPLY:
The range of voltage on
machine 240 volts A.C. In the ECM
method a constant voltage has to be
maintained. At high current densities,
the metal removal rate is high and at
low current densities, the metal
removal rate is low. In order to have a
metal removal of the anode a
sufficient amount of current has to be
given. The Power supply is one of the
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6. main sources in our project. Because
of the material removal rate is
calculated depends on amount of
power supplied to the work piece.
3.3WORKPIECE:
The work piece is stainless
steel 202.it is a general purpose
stainless steel. Decreasing nickel
content and increasing manganese
results in weak corrosion resistance.
fig.3.2
Length of the ss 202 = 35.7cm
Diameter of the ss202 = 0.8cm
PROPERTIES:
SS202 Material is
selected as anode based on
different properties.
PHYSICAL PROPERTIES:
PROPERTY VALUE
Density 7.80 g /
cm3
Thermal
expansion
17× 10-6
/
k
Modulus of
Elasticity
200
GPa
Thermal
Conductivity
15 W /
mk
MECHANICAL
PROPERTIES:
PROPERTY
VALUE
Proof Stress 310
MPa
Tensile Strength 655
MPa
Elongation 40 %
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7. 3.4 Tool:
The tool is iron. At increasing the
carbon content of the iron will
increase the tensile strength and iron
hardness. The iron is suitable for
cathode and easily reacts with anode.
Length of the iron = 15cm
Diameter of the iron = 1cm
fig.
Low pressure Phase diagram of iron
fig.3.3
3.5 Electrolyte:
The electrolyte is hydrochloric acid.
Boiling, melting point, density and ph
depends on the concentration. It is a
colourless and transparent liquid,
highly corrosive, strong mineral acid.
HCL is found naturally in gastric acid.
The HCL is highly concentrated. In
that process amount of HCL is 550ml.
fig.3.4
3.6 Electrolytic tank:
Length of the tank = 20 cm
Height of the tank = 12.5 cm
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8. 3. EXPERIMENTAL
ELECTROCHEMICAL
MACHINING
CALCULATION FOR
CONSTANT POWER
SUPPLY
3.1. TABULATION 1:
The material removal rate is
calculated by immerging distance of
anode and cathode. 240 V current
supply is input for the anode and
cathode. The supply 240 V current is
constant. The MRR is calculated after
15 minutes by using the formulas.
S.NO VOLTAGE
(Volts)
TIME
(Min)
ELECTRODE
DISTANCE
(cm)
MATERIAL
REMOVAL
RATE(cm3
min-1
)
1. 240 15 12 1.191
2. 240 15 8 1.186
3. 240 15 6 1.157
Table.2
The material removal rate is
calculated by electrode distance of
anode and cathode. 240 V current
supply is input for the anode and
cathode. The supply 240 V current is
constant. The MRR is calculated after
15 minutes by using the formulas.
3.2. FORMULAE USED:
MATERIAL REMOVAL
RATE:
It is a ratio between volume of work
piece to time taken for the material
removal.
MRR = (VOLUME OF WORK
PIECE) / (TIME TAKEN)
UNIT: cm3
/min
S.NO VOLT
AGE
(Volts)
TIM
E
(Min)
IMMER
GEDDIS
TANCE
(cm)
MATER
IAL
REMO
VALRA
TE(cm3
min-1
)
1. 240 15 2.8 1.191
2. 240 15 3.1 1.186
3. 240 15 6.5 1.157
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9. Volume of work piece:
V = πr2
h
r - Radius of the work piece, h -
Length of the work piece
3.3. Calculation:
Volume of removed material, V= πr2
h
V = π× (0.39)2
×2.8
V = 0.4778×2.8
V =1.34 cm3
Volume of remaining
Material, V= πr2
h
V= π× (0.4)2
×32.9
V= 0.5026× 32.9
V= 16.53 cm3
Total volume = Volume of removed
material + Volume of remaining
material = 1.34 + 16.53
= 17.87 cm3
MRR = (VOLUME OF WORK
PIECE) / (TIME TAKEN)
MRR= 17.87 / 15
MRR= 1.1913 cm3
/min
3.4. RESULT:
Fig 10 & 11
When the immerged distance is
increased the material removal rate
decreased
When the electrode distance is
increased the material removal rate
increased.
4. EXPERIMENTAL
ELECTROCHEMICAL
MACHINING
CALCULATION FOR
VARIABLE POWER
SUPPLY:
0
10
20
MRR VS
ELECTRODE
DISTANCE
MRR
VS
ELECT
RODE
DIST…
1.1
1.15
1.2
2.8 3.1 6.5
IMMERGED
DISTANCE VS…
IMME
RGED
DISTA
NCE
VS…
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10. The material removal rate is
calculated by varying the power
supply. The material removal rate is
calculated up to 30V. The power
should be varied every 10 V supply.
COMPONENTS:
RPS meter
Power supply
Work piece
Tool
Electrolyte
Electrolytic tank
4.1. RPS METER:
RPS is stand for Regulator Power
Supply. The function of the meter is
varying the power supply. The range
of meter is 0-30V.
In this tabulation the voltage is varied
from 0-30V. At the same time the
immerged distance (2.8cm) and time
(45min) will be constant. The voltage
is increase means the material
removal rate also increased.
S.N
O
VOLTA
GE
(volts)
TIM
E
(min
)
IMMERG
ED
DISTANC
E
(cm)
MATERI
AL
REMOV
AL
RATE(cm
3
min-1
)
1. 10 45 3.1 0.118
2. 20 45 3.1 0.156
3. 30 45 3.1 0.194
S.N
O
VOLT
AGE
(volts)
TI
ME
(mi
n)
IMMER
GED
DISTAN
CE
(cm)
MATE
RIAL
REMO
VAL
RATE(c
m3
min-
1
)
1. 10 45 2.8 0.129
2. 20 45 2.8 0.167
3. 30 45 2.8 0.216
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11. In this tabulation the voltage is varied
from 0-30V. At the same time the
immerged distance (3.1cm) and time
(45min) will be constant.
RESULT:
Fig 13 & 14
The applied voltage is increased
means the material removal rate also
inceased. In the first graph the
workpiece immerged distance is 2.8
cm and the second graph the
workpiece immerged distance is 3.1
cm. In these two graphs material
removal rate value is taken in X-axis
and current voltage is taken in Y-
axis. So the graph between material
removal rate vs votage.
5. CONCLUSION:
When the immerged distance is
increased the material removal rate
decreased and then the electrode
distance is increased the material
removal rate increased. The voltage
increased means the material removal
rate is increased. So the material
removal rate is dependent upon the
voltage immerged distance.
6. APPLICATION:
Some of the very basic applications of
ECM include:
1. Die-sinking operations.
2. Drilling jet engine turbine blades.
3. Multiple hole drilling.
4. Machining steam turbine blades
within close limits.
0
5
10
15
20
25
30
35
0.118 0.156 0.194
MRR VS VOLTAGE
MRR VS
VOLTAGE
0
10
20
30
40
0.129 0.167 0.216
MRR VS VOLTAGE
MRR VS
VOLTAGE
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12. 7. REFERENCE:
1. Journal of the Taiwan Institute of
Chemical Engineers, Volume 45,
Issue 3, May2014, Pages840-845
M.H. Abdel-Aziz, I. Nirdosh, G.H.
Sedahmed.
2. ProcediaCIRP, Volume8, 2013,
Pages265-270 F. Klocke, M. Zeis, S.
Harst, A. Klink, D. Veselovac, M.
Baumgärtner.
3. journal of Manufacturing
Processes, Volume 14, Issue 1,
January 2012, Pages62-70 M. Burger,
L. Koll, E.A. Werner, A. Platz.
4. Manufacturing Process Selection
Handbook, 2013, Pages 205-226
K.G. Swift, J.D. Bookers
8. EXPRIMENT PICTURES:
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13. INTERNATIONAL CONFERENCE ON CURRENT TRENDS IN ENGINEERING RESEARCH, ICCTER - 2014
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