23-09-2014, 11:10 AM
OPTIMIZATION AND EXPERIMENTAL INVESTIGATION ON EN19 USING
HEXAGONAL SHAPED ELECTRODE IN ECM PROJECT REPORT
OPTIMIZATION.pdf (Size: 1.21 MB / Downloads: 42)
ABSTRACT:-
Electrochemical machining (ECM) has inaugurated itself as one of the major other possible way
to conventional methods for machining hard materials and complicated outlines not having the
residual stresses and tool wear. Electrochemical machining has vast application in automotive,
Aircrafts, petroleum, aerospace, textile, medical and electronic industries. Studies on Material
Removal Rate (MRR) are of extremely important in ECM, since it is one of the factors to be
Determined in the process decisions. So the aim of present work is to investigate the metal
removal rate, overcut diameter and surface roughness of EN19 alloy steel of diameter 13cm as
work piece by using hexagonal shaped Brass electrode and brine solution as electrolyte by using
Taguchi approach. Then optimizing to find best setting of process variables for higher MRR,
lower surface roughness and overcut. Three parameters were chosen as process variables are:
voltage, tool Feed rate and Electrolyte concentration.
INTRODUCTION
Electrochemical machining is a nontraditional machining process which is used to machine hard
materials which cannot be machined easily without causing any harm to tool. This can be used
for mass production and can machine external and internal of any geometry. But use of it is
limited only to electrically conductive materials.
Unlike conventional processes ECM removes metal atom by atom.it can be regarded as a
solution to a variety of metal removal problems such as cavity sinking, contouring machining
and machining helices(rifle barrels) [1].
LITERATURE SURVEY
In this chapter, some research papers related to electrochemical machining are reported. They
deal with material removal rate, surface roughness, overcut, tool shape, concentration of
electrolyte, micro electrochemical machining, tool design and other responses.
EXPERIMENTATION
In this chapter, experimentation is discussed which consists about work piece specification,
Machine specification, tool design, concentration measurement, formation of the L-9 orthogonal
array based on Taguchi design and response calculations Orthogonal array decreases the total
number of experiments to be conducted. Total nine experimental runs have been conducted and
MRR, overcut diameter and surface roughness are calculated. Multi response optimization of
quality loss function is used to find best parameter setting as single response optimization cannot
be used in Taguchi design.
SPECIFICATION OF WORKPIECE MATERIAL:
The material that was selected for experiment was EN19 alloy steel .the description of the
Material EN19 alloy steel is given in table no. 4.1 and chemical composition in table 4.2and
mechanical and thermal properties are given in table no. 4.3 .the dimension of work piece is 50
mm diameter and 10 mm thickness. The work piece material is circular in shape. 2 pieces
ofEN19 alloy steel were taken to conduct 9 experiment runs .3 experiments were conducted on
each side of the work piece
CONTROL PANEL
On control panel we regulate the current (I), voltage (V), feed rate (F) and time (T) for duration
of every experiment. The power supply is a perfect combination of high electrical current, power
electronics and accurately programmable microcontroller based technologies. Since the machine
works at very low voltage so there are no chances of any electrical shocks during operation.in
Control Panel .there is a siren to indicate the end of experiment after allotted time to an
Experiment. Control panel is shown in figure 3.2.2.1
ELECTROLYTE CIRCULATION
The electrolyte is pumped from tank filled with brine solution. First it is fed to filter then it is fed
to the job. Used electrolyte will return back to the tank. The hydroxide sludge arising will Settle
at the bottom of the tank & can be easily drained out. Electrolyte supply shall be controlled by
flow control valve. Extra electrolyte flow is passed back to the tank.. All fittings are of corrosion
resistant material or of Stainless steel, as necessary.
TOOL DESIGN
A tool is required for desired way of removing material from the work piece. Different tool
shapes are required for different use giving different shapes to the work piece for same
conditions.so a tool was made as follows:
Tool for electrochemical machining was made of brass .A solid cylindrical rod of brass of 15mm
Diameter was taken and a piece of 65mm was cut .two faces were smoothen by facing the two
Faces in lathe and maintained length 60 mm. diameter was reduced to 12mm diameter by turning
In lathe and M12 external thread was made on one end of rod using thread die as tool holder has
M12 internal thread. A through hole was made of diameter 5mm at the Centre using 5mm drill
Bit from a hexagonal shaped rod a piece of 6mm thick piece was cut. A 4mm hole was made at
Centre using 4mm drill bit .both these parts were brazed to make tool.
CONCLUSION
Experiments were conducted using designed hexagonal shaped brass electrode and machining
setup in Taguchi method .control factors voltage, tool feed rate and concentration were varied to
get 9 experiments.at the end MRR, diameter -overcut and surface roughness measurements were
done.
RESULT AND DISCUSSION ON MRR
The machinability of a material in ECM depends on many factors as voltage ,tool feed rate
,concentration, tool diameter, tool design, electrolyte flow rate and many more.in my case of
study voltage, tool feed rate and concentration are input factors and others are kept constant.
In this two tables and six graphs are discussed.
CONCLUSION
In this study of ECM process on EN19 alloy steel by hexagonal shaped electrode I considered 9
experiments by Taguchi design. .in this three factors were considered that are voltage, tool feed
rate and electrolyte conctration. These 9 experiments were conducted to obtain high MRR, low
overcut and low surface roughness. optimization by quality loss function was used to obtain
suitable combination of factors to get large MRR, small overcut and small surface roughness. I
arrived at following conclusion:-
1. Among 3 factors feed rate is effecting MRR most then comes voltage and at last electrolyte
concentration.
2. For surface roughness, feed rate effects it most then concentration and at last voltage.
3. Tool feed rate effects most to overcut at second rank is voltage and at third rank is
concentration which affects most to overcut.
4. In optimizing the quality loss function, it is found that experiment run no 5 is most optimal
i.e. voltage=10V, tool feed rate= 0.4 mm/min and electrolyte concentration =22.03g/l for
maximizing MRR and minimizing both overcut and surface roughness.