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Title: machining process
Description: explanation of machining and briefing EDM and ECM
Description: explanation of machining and briefing EDM and ECM
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1
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b) To get a good tolerance and finishing
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2
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Material is removed from the workpiece by a series of
rapidly recurring current discharges between two electrodes, separated by a
dielectric liquid and subject to an electric voltage
...
When the distance between the two
electrodes is reduced, the intensity of the electric field in the volume between the
electrodes becomes greater than the strength of the dielectric at least in some
point, which breaks, allowing current to flow between the two electrodes
...
As
a result, material is removed from both the electrodes
...
Adding
new liquid dielectric in the inter-electrode volume is commonly referred to as
flushing
...
3
...
) Electrod Characteristics
...
Electrod Characteristic
EDM
Easily to be machine to various shape
ECM
Can be machine to various shape
The cost is affordable
Harden with a fragile structure
Can get the accurate dimension
Non rusty
Highly finishing surface structure
Affordable price
Nisbah kehausan yang tinggi
A good conductor
Liquid Characteristics
EDM
ECM
Non Toxic
A good conductor
Didnt cause rusty
Flow above 50 and 150 pal (pressure)
Have a characteristic of sat water and
Stand to highly temperature
Suit to dielectric strength
Natrium Chloride
Electroliasis Liquid
4
...
•
A process of melting or removal of particles of metal particles with fireworks shot
from a special electrode
...
•
Conductor of electricity between the electrode and the workpiece which produces
sparks 3000 degrees Celsius temperature
...
5
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List
up three (3) important factor in choosing a right electrode
...
Highly wear ratios rate
...
Produce a good surface finishing
c
...
What is the meaning of wear ratio and state the three (3) type of wear
...
Wear is related to interactions between surfaces and more specifically the
removal and deformation of material on a surface as a result of mechanical action
of the opposite surface
...
Three types of wear :(a) Abbrasive wear
(b) Surface fatigue
(c) Erosive wear
7
...
•
The electric supply only provide a low voltage, but the current used were high for
example between 5V to 24V whereas the current is 500amp to 25000amp
...
Dc also
supply the current to the machine for the melting process of workpiece
...
What was happened to servo motor when Dc Arcing occur
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The servo-mechanism for insuring
proper sparking between the workpiece and electrode is, in reality, typically a
voltage regulator
...
9
...
•
DC arcs are primarily caused by one thing: bad flushing
...
•
The sludge acts like part of the electrode and attracts sparks that arc across the
dielectric fluid and faithfully reproduce their shape in the steel
...
The longer it persists, the bigger the pit
...
This happens because the filters
are full, or not fine enough to filter out the EDM sludge and grit
...
•
Some manufacturers claim that their machines have software that prevents DC
arcing, and to a great extent they do
...
Some have a high speed oscillating effect that
improves the flushing as well
...
10
...
True, improved EDM sinker
technologies have the ability to monitor the condition of the EDM process and
make adjustments to run more efficiently
...
Often, the production of fine surface finishes in the cavity does not come
with the technological improvements of the EDM sinker unless an electrode
material of higher quality is used
...
For many of the applications in the
market today specifically medical and aerospace meeting the demands of the
business environment is not congruent to trying to save a few dollars on the
electrode material
...
Describe simply the relation between metal surface output and sparkle frequency
...
In general, the material
characteristics of the electrode play a much larger role in achieving a fine surface
finish than one might think
...
•
A common belief in the mol making industry is that a lower quality electrode
material can be used to produce superior surface finishes if a high quality EDM
machine is used
...
12
...
•
When the distance between the two electrodes is reduced, the intensity of the
electric field in the volume between the electrodes becomes greater than the
strength of the dielectric (at least in some points, which breaks, allowing current to
flow between the two electrodes
...
As a
result, material is removed from both the electrodes
...
The higher the electricity, the faster the rate
of metal remover
...
State the difference between unconventional machining and conventional machining
...
Quality finishing and produce good tolerance
14
...
Draw and label
each of component of EDM Machining
...
Describe the meaning below :a
...
Electrolysis is commercially highly important as a stage in
the separation of elements from naturally occurring sources
such as ores using an electrolytic cell
...
) Electrolyte :
•
An electrolyte is any substance containing free ions that make
the substance electrically conductive
...
Commonly, electrolytes are
solutions of acids, bases or salts
c
...
What is the function of electrode in ECM ( Electro Chemical Machining) and state three
(3) characteristic of choosing a good electrode
...
On outer
surface of ECM electrode coated with plastic except on the place where
removing happened
...
Title: machining process
Description: explanation of machining and briefing EDM and ECM
Description: explanation of machining and briefing EDM and ECM