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By: Michael Banks & Brenden Barboza
Die-Sink EDM Dielectric Liquid
Wire Cut EDM Diamond Guides
Small Hole EDM Electrodes
Precision Transistor Circuits
Machining RC Circuits
Numerical Control Vacuum Tube
Computer Circuits
Numerical Control Closed Loop
Hole Popper Manufacturing
Key Terms cont.
Dialectric strength
Dielectric filter
Why is There Liquid in an Electrical

The main purpose is for flushing

it prevents premature spark discharge
It flushes away the debris
The liquid also serves to cool down the
work piece and the electrode
In Sinker EDMs the liquid is paraffin,
kerosene or a silicon-based dielectric
For Wire EDMs it is usually deionized
EDM Fluid cont.
Quenching refers to the rapid cooling of
the EDM surface by a dielectric liquid
The dielectric filter removes particles so
as not to clog the machine and maintain
accuracy of the electrode
Dielectric strength refers to the amount
of voltage needed to ionize the dielectric
fluid between the electrode and the work
The Type of Generators Used
(The Two Broad Categories)

RC Circuits Transistors
In comparison, This way allows
the RC Circuits for more control
allow for more of
control of the The shape of the
duration of pulses pulse
The time between
The amplitude
History of Die-Sink EDM
Russian Scientists: B. R. Butinzky and N. I.
Lazarenko 1940s
After a failed attempt of preventing erosion of heavy
metals, these scientists discovered a way to control it by
immersing the electrodes in a dielectric fluid
Used a Resistor-Capacitor Circuit to charge the electrodes
Simultaneously, an American Team was working on
a EDM machine for removing broken drills and taps
from Aluminum Castings
Starting from feeble starts, the team eventually
incorporated a vacuum tube circuit which could produce
thousands of sparks per second, compared to their first
design which could only produce 60 sparks per second
How does a Sinker EDM work???
(Also Called: Cavity Type EDM or Volume EDM)

The work piece is submerged in an oil, or other

dielectric liquid
The sparks occur when the electrode submerges
into the dielectric liquid
A plasma channel is formed which causes and
sparks are emitted
The sparks are controlled in certain positions
As the piece is eroded the electrode moves about
Compared to Wire Cut EDMs, Sinker EDMs cause
more residual stress on a part
History of Wire Cut EDM
Arose in the 1960s for the purpose of making
tool, mostly dies, from hardened steel
The First Numerical Controlled EDM was created
in the USSR in 1967
Machines with the ability to follow master
drawings were later produced in the late 1960s
by the Andrew Engineering Company
Computer Numerical Controlled EDMs (1976)
soon followed and provided better accuracy as
well as the ability to produce more complicated
How does a Wire Cut EDM
The tool electrode is a simple wire, usually copper or
To prevent erosion, the active wire is wound up in
two spools that are constantly wound and unwound
These wires are held by two diamond guides (an upper
and lower guide)
These guides can control movement in the x-y-z-u-v axises
More modern machines can control xyz-uvijkl axis
This allows for tapered and transitionary pieces
The material is submerged in a dielectric liquid,
generally deionized water
How Does a Wire Cut EDM Work cont.

The wire releases electrical discharge to

cut the piece
The wire never makes contact with the
The discharge erodes the material and
provides a clean surface that generally
does not require additional machining
Lets See One in Action!

This EDM is machining a Gear Punch The dielectric liquid is being released
v=TM-xTFKu from the same hole as the wire
ReY Also noticeable is the cylindrical gear
that changes the EDM machines axis
The wire is made of re-usable
Which is a cost effective alternative to
brass or copper
Applications of EDM
Prototype Production
Coinage Die Making

Small Hole Drilling

Metal Disintegration

Closed Loop Manufacturing

Rapid Prototyping
The EDM is used widely in the mold tool
and Die making industries
However, Automotive, Aerospace and the
Electronics Industries are beginning to
incorporate EDM Machines for prototyping
is due to their generally low production
Coinage Die Making
Used in creating molds for Jewelry
A stamp is created and used as a Drop
Hammer to produce stamped flats
For this process, the EDM is usually
submerged in an Oil based dielectric
Further processes may be enameled,
electroplated or hand engraved
Small Hole Drilling
EDM Machines can create cuts that can
be measured in nanometers and
In most cases, the small hole will be a
through hole
Newer designs have a super drill called a
Hole Popper
This process can create Through AND Blind
Metal Disintegration
Since the EDM Machine works by eroding
material, many companies use it for the
sole purpose of removing broken tools
and bits from in a widget
The accuracy of the machine allows for
only the specific part to be removed,
leaving any important nuts and bolts or
Closed Loop Manufacturing
Since EDM Machines can produce
complex interchangeable parts from a
single block of material, they are
sometimes used as the sole process of
This can cut down expenses since only
one operator is needed, and no other
machine would need to be turned on
This isnt a normalized processes yet,
Advantages and
Advantages Disadvantages
Can produce complex shapes There is a slow material
Can extremely hard material removal rate
to very low tolerances Fire hazards present when
Can machine small work working with an oil based
pieces dielectric fluid
No distortion since the tool Sharp corners can be difficult
never touches the machined due to electrode wear
part Power consumption is very
A good finishing can be high
produced through normal Excessive tool wear occurs
methods, and a fine finishing
can be produced through Non-conductive materials
repeated pathings can only be machined using
Tapered Holes can be made additional set-ups (Which
means more money)
Very small holes can be made