AN EXPERIMENTAL STUDY OF ELECTRICAL
DISCHARGE MACHINE (EDM) PARAMETERS TO THE STAVAX SURFACE INTEGRITY
CHAPTER 1
INTRODUCTION
1.1 PROJECT BACKGROUND
EDM is the thermal erosion process in which metal is removed
by a series of repeated electrical discharges between a cutting tool acting as
an electrode and a conductive workpiece, in the presence of a dielectric fluid.
Discharge occurs when there are voltage gap between the electrode and
workpiece. Heat from the discharge vaporizes minute particles of workpiece
material, which are then washed from the gap by the continuously flushing
dielectric fluid. The intensity of the electric
field in the volume between the electrodes becomes
greater than the strength of the dielectric when the distance between the two
electrodes is reduced which breaks, allowing current to flow between the two
electrodes.
Some of the advantages of EDM include
machining of:
1. Complex shapes that would otherwise
be difficult to produce with conventional cutting tools.
2. Extremely hard material to very close
tolerances.
3. Very small work pieces where conventional cutting
tools may damage the part from excess cutting tool pressure.
4. There is no direct contact between tool and work
piece. Therefore delicate sections and weak materials can be machined without
any distortion.
5. A good surface finish can be
obtained.
6. Very fine holes can be easily
drilled.
The experiment will
conducted to the material called stavax which is known as Uddeholm Stavax ESR. Uddeholm is a multinational producer of high alloyed tool
steel with production in
Hagfors, Sweden. Electroslag
remelting (ESR), known as
electro-flux remelting, is a
process of remelting and refining steel and other alloys.
1.2 PROBLEM
STATEMENT
There are some limitations of EDM
die sinking that are relatively slow rate of material removal. This may affect
from the gap between electrodes that strike to towards the workpiece at one
time. Besides that, EDM die sinking involving high power consumption in its
process. If in industries, it process may require high energy power to running
each process. Hence, high cost need to consider accommodating the process of EDM die sinking
that will minimize profit. In addition, the process of EDM die sinking may
affect to the workpiece in term of its layer. Surface defects are important in
term of quality and accuracy of tolerance. If their tolerance is low, the
surface roughness of the workpiece in a good condition.
Otherwise,
surface roughness was effect the safety for the user if have a burr at the workpiece
or product. A value of surface roughness may be specified so that expensive
finishing processes are eliminated, thereby reducing costs, or alternatively to
improve the mechanical properties of a component. Repeating
strike of electrode onto the workpiece will give some damaged at material
structured inside of workpiece.
1.3 OBJECTIVES
OF THE PROJECT
The
importance of this project is stated below:
1. To identified best parameters in EDM
die sinking machining.
2. To evaluate surface and microstructure
defect from the working of EDM die sinking.
3. To investigate the surface roughness
for small thickness in EDM dies sinking.
1.4 SCOPE
OF THE PROJECT
Scopes
for this project is based on objectives that have created and there are the several
scopes that will be carrying out:
1.
Focusing on getting the best parameters to get the good finished surface by EDM
die sinking machine.
2.
Surface defects and microstructure of Stavax material will evaluate by using
some mechanism.
3.
In term to get a higher surface finish and a lower roughness in EDM Die Sinker
by apply several techniques and testing until get the several results.
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