ISBN: 378-26-138420-01
INTERNATIONAL CONFERENCE ON CURRENT TRENDS IN ENGINEERING RESEARCH, ICCTER - 2014
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
Decreased and then the electrode
The aim of this project is to study
distance is increased the material
the material removal rate in an
removal rate increased. The voltage
electrochemical machining process
increased
of SS 202 material. When the
removal rate is increased. So the
electrodes are immerged in the
material removal rate is dependent
electrolyte
are
upon
and
distance.
removed
the from
electrons the
anode
means
the
the
voltage
immerged
deposited in the electrolytic tank.
Results
After taken the first reading the
removal rate is dependent on three
electrode
factors
immerged
in
the
indicated that
material
material
electrolyte again with high distance.
1) Power supply,
So the electrons are removed from
2) Distance between anode and
the anode for the given distance.
cathode,
The electrode distance also varied.
3) Depth of immersion.
When the immersion depth is increased the material removal rate
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CHAPTER-1
studied by measuring the limiting
INTRODUCTION
current of the anodic dissolution of a vertical copper cylinder in phosphoric
IMPORTANCE OF ECM:
acid.
In electro chemical machining process there is no residual stress induced in the work piece. But other
amplitude
of
oscillation,
and
phosphoric
acid
of
conditions,
electrode
rate of anodic dissolution up to a
low voltages compared to other
maximum of 7.17 depending on the
processes with high metal removal can
and
oscillation was found to enhance the
no tool wear; machining is done at
dimensions
were
frequency
range
residual stress are induced. There is
small
studied
concentration. Within the present
machining process like lathe the
rate;
Parameters
operating
be
conditions.
The
mass
transfer coefficient of the dissolution
controlled; hard conductive materials
of the oscillating vertical copper
can be machined into complicated
cylinder in H3PO4 was correlated to
profiles; work piece structure suffer
other parameters by the equation:
no thermal damages; suitable for mass production work and low labour
Sh=0.316Sc0.33Rev0.64.The
requirements.
importance of the present study for increasing the rate of production in
CHAPTER-2
electro polishing and electrochemical
LITERATURE REVIEW
machining,
M.H. Abdel-Aziz - May 2014:
electrometallurgical processes limited
and
other
by anode passivity due to salt The effect of electrode oscillation on
formation such as electro refining of
the rate of diffusion-controlled anodic
metals was highlighted.
processes such as electro polishing and electrochemical machining was
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F. Klocke – 2013:
validated by the example of a compressor blade. Finally a new
In order to increase the efficiency
approach for an inverted cathode
of jet engines hard to machine
design process is introduced and
nickel-based and titanium-based
discussed.
alloys are in common use for aero engine components such as blades
and
integrated
blisks
(blade
disks).
Electrochemical
M. Burger - January 2012: Nickel-base
Here
single-crystalline
materials such as LEK94 possess
Machining
excellent
thermo-mechanical
(ECM) is a promising alternative
properties
to milling operations. Due to lack
combined with low density compared
of appropriate process modeling
to similar single-crystalline materials
capabilities
used in aero engines. Since the
beforehand
still
high
temperatures
components of aero engines have to
knowledge based and a cost
fulfill demanding safety standards, the
intensive cathode design process
machining of the material used for
is passed through.
these components must result in a high geometrical accuracy in addition
Therefore this paper presents a multi-physical
approach
modeling
ECM
the
at
to a high surface quality. These
for
requirements can be achieved by
material
electrochemical
removal process by coupling all
electrochemical
relevant conservation equations.
(ECM/PECM). In order to identify
The resulting simulation model is
proper
machining
PECM
the
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and
precise machining
parameters
for
electrochemical
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characteristics
dependent
on
the
microstructure
and
the
chemical
homogeneity
of
LEK94
CHAPTER-3 ELECTROCHEMICAL
are
MACHINING PROCESS:
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 machininggap, the applied voltage and the electrical electrolyte densities
conductivity used. yield
of
Low
the
current
inhomogeneous
electrochemical
dissolution
of
different micro structural areas of the
fig.3.1
material and lead to rough surfaces.
In ECM, the principles of electrolysis
High surface qualities can be achieved
are used to remove metal from the
by
work pieces. FARADAY’S LAWS of
employing
electrochemical
homogenous
dissolution,
which
electrolysis may be stated as: “the
can be undertaken by high current
weight of substance produced during
densities.
special
electrolysis is directly proportional to
electrode was developed for the
the current which passes the length of
improvement of the quality of side-
time of the electrolysis process and
gap machined surfaces.
the equivalent weight of the material,
Furthermore,
a
which is deposited”. The work piece is made the anode and the tool is made the cathode. The electrolyte is
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filled in the beaker. As the power
3.1 Experimental setup:
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 fig.3.1A
work piece automatically at constant velocity to control the gap between
COMPONENTS:
the electrodes the tool face has the
Power supply
reverse shape of the desired work
Work piece
piece. The sides of the tool are
Tool
insulated to concentrate the metal
Electrolyte and Electrolytic tank
removal action
3.2 POWER SUPPLY:
at the bottom face of the tool. The
The range of voltage on
dissolved metal is carried away in the
machine 240 volts A.C. In the ECM
flowing
positive
method a constant voltage has to be
supply is supplied to Stainless Steel
maintained. At high current densities,
202 material.
the metal removal rate is high and at
electrolyte.
The
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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main sources in our project. Because
PHYSICAL PROPERTIES:
of the material removal rate is calculated depends on amount of
PROPERTY
power supplied to the work piece.
VALUE
Density
3.3WORKPIECE:
7.80 g / cm3
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.
17Ă— 10-6 /
Thermal expansion Modulus
k of
Elasticity
200 GPa
Thermal Conductivity
15 W / mk
MECHANICAL PROPERTIES: PROPERTY VALUE
fig.3.2
Length of the ss 202 = 35.7cm
Proof Stress
Diameter of the ss202 = 0.8cm
MPa
PROPERTIES: SS202
310
Tensile Strength Material
is
655 MPa
selected as anode based on
Elongation
40 %
different properties.
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3.4 Tool:
3.5 Electrolyte:
The tool is iron. At increasing the
The electrolyte is hydrochloric acid.
carbon content of the iron will
Boiling, melting point, density and ph
increase the tensile strength and iron
depends on the concentration. It is a
hardness. The iron is suitable for
colourless and transparent liquid,
cathode and easily reacts with anode.
highly corrosive, strong mineral acid.
Length of the iron = 15cm
HCL is found naturally in gastric acid.
Diameter of the iron = 1cm
The HCL is highly concentrated. In that process amount of HCL is 550ml.
fig.3.4
fig.
3.6 Electrolytic tank:
Low pressure Phase diagram of iron
Length of the tank = 20 cm Height of the tank = 12.5 cm
fig.3.3
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S.NO
3. EXPERIMENTAL
VOLTAGE (Volts)
ELECTROCHEMICAL
MATERIAL
(Min)
ELECTRODE DISTANCE (cm)
TIME
REMOVAL RATE(cm3 min-1)
MACHINING 1.
240
15
12
1.191
CONSTANT POWER
2.
240
15
8
1.186
SUPPLY
3.
240
15
6
1.157
CALCULATION FOR
3.1. TABULATION 1: The S.NO
VOLT AGE (Volts)
TIM E
IMMER GEDDIS TANCE
(Min) (cm)
MATER IAL
Table.2 material removal
rate
is
calculated by electrode distance of
REMO VALRA TE(cm3 min-1)
anode and cathode. 240 V current supply is input for the anode and cathode. The supply 240 V current is
1.
240
15
2.8
1.191
2.
240
15
3.1
1.186
3.
240
15
6.5
1.157
removal
rate
constant. The MRR is calculated after 15 minutes by using the formulas.
The
material
3.2. FORMULAE USED: MATERIAL REMOVAL RATE:
is
It is a ratio between volume of work
calculated by immerging distance of
piece to time taken for the material
anode and cathode. 240 V current
removal.
supply is input for the anode and cathode. The supply 240 V current is
MRR = (VOLUME OF WORK
constant. The MRR is calculated after
PIECE) / (TIME TAKEN)
15 minutes by using the formulas.
UNIT: cm3 /min
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Volume of work piece:
MRR VS ELECTRODE DISTANCE
2
V = πr h r - Radius of the work piece, h Length of the work piece
20 10 0
MRR VS ELECT RODE DIST…
3.3. Calculation: Volume of removed material, V= πr2h
IMMERGED DISTANCE VS… 1.2
V = π× (0.39)2×2.8 V = 0.4778×2.8 3
IMME RGED DISTA NCE VS…
1.15
V =1.34 cm
1.1
Volume of remaining
2.8 3.1 6.5
Material, V= πr2h
Fig 10 & 11
V= π× (0.4)2×32.9
When the immerged distance is
V= 0.5026× 32.9
increased the material removal rate
V= 16.53 cm3
decreased
Total volume = Volume of removed
When
material + Volume of remaining
the
electrode
distance
is
increased the material removal rate
material = 1.34 + 16.53
increased.
= 17.87 cm3
4. EXPERIMENTAL
MRR = (VOLUME OF WORK PIECE) / (TIME TAKEN)
ELECTROCHEMICAL
MRR= 17.87 / 15
MACHINING
MRR= 1.1913 cm3/min
CALCULATION FOR
3.4. RESULT:
VARIABLE POWER SUPPLY:
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The
material
removal
rate
is
calculated by varying the power
S.N VOLT
TI
IMMER
O
AGE
ME
GED
(volts)
(mi
DISTAN
n)
CE
supply. The material removal rate is calculated up to 30V. The power should be varied every 10 V supply.
MATE RIAL REMO VAL RATE(c m3 min1 )
(cm)
COMPONENTS: RPS meter Power supply Work piece Tool Electrolyte
1.
10
45
2.8
0.129
2.
20
45
2.8
0.167
3.
30
45
2.8
0.216
from 0-30V. At the same time the
Electrolytic tank
immerged distance (2.8cm) and time
4.1. RPS METER:
(45min) will be constant. The voltage
RPS is stand for Regulator Power
is
Supply. The function of the meter is
increase
means
the
material
removal rate also increased.
varying the power supply. The range
S.N
VOLTA
TIM
IMMERG
of meter is 0-30V.
O
GE
E
ED
(volts)
(min
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
In this tabulation the voltage is varied
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In this tabulation the voltage is varied
cm. In these two graphs material
from 0-30V. At the same time the
removal rate value is taken in X-axis
immerged distance (3.1cm) and time
and current voltage is taken in
(45min)
axis. So the graph between material
will
be
constant.
Y-
removal rate vs votage.
RESULT:
5. CONCLUSION:
MRR VS VOLTAGE
When the immerged distance is
35
increased the material removal rate
30 25
decreased and then the electrode
20 MRR VS VOLTAGE
15 10
distance is increased the material removal rate increased. The voltage
5 0
increased means the material removal 0.118
0.156
0.194
rate is increased. So the material
MRR VS VOLTAGE
removal rate is dependent upon the
40
voltage immerged distance.
30
6. APPLICATION:
20
MRR VS VOLTAGE
10
Some of the very basic applications of
0 0.129
0.167
ECM include:
0.216
1. Die-sinking operations.
Fig 13 & 14 The applied voltage is increased
2. Drilling jet engine turbine blades.
means the material removal rate also 3. Multiple hole drilling.
inceased. In the first graph the workpiece immerged distance is 2.8 cm
and
the
second
graph
4. Machining steam turbine blades
the
within close limits.
workpiece immerged distance is 3.1
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7. REFERENCE:
8. EXPRIMENT PICTURES:
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. Baumg채rtner. 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
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