What's Electrical Discharge Machining (EDM)6

What's Electrical Discharge Machining (EDM)?
Electrical Discharge Machine (EDM) is a type of machining operation employed for shaping
conductive workpieces into geometrically complex parts. Electrical discharge machines are
particularly well suited for machining components that have complicated contours or subtle cavities
that would be hard to produce along with other conventional machining equipment. The process
involves supplying electricity to both shaping tool along with the workpiece and then bringing the
tool into close proximity using the workpiece, that is completely immersed inside a dielectric fluid
bath. This proximity causes the electrical field intensity between the tool and workpiece to
overcome the strength of the dielectric fluid, and creates a series of electrical discharges between
them. These electrical discharges remove material in the workpiece, and also the pattern or form of
material removed relies upon the shape of the tooling electrode. Following the machining operation,
the dielectric fluid is replaced between the electrodes. Apart from serving as a dielectric backward
and forward electrodes, the fluid also plays a key role in the machining process, because it is
accustomed to eliminate the removed material and cool the machined area. The nature from the
process is really that, while materials are being taken off the workpiece; the tooling electrode can
also be gradually eroded, making periodic replacement necessary.
The electrical discharge machining process is extremely precise and usually utilized in the production
of components that are typically complex and need extreme accuracy. In addition, another section
of application that EDMs perform above par is incorporated in the machining and shaping of hard or
exotic materials such as titanium, Hastelloy, Kovar, Inconel, in addition to hardened steel. However,
the only real caveat using the electrical discharge machining process is that it could be simply be
used with conductive materials. Taiwan EDM
You will find essentially two kinds of electrical discharge machines, which differ within the kind of
tooling electrode that they are outfitted with. They are sinker EDMs and wire EDMs. The sinker EDM,
also referred to as a ram EDM uses a shaped tooling electrode to facilitate the machining process.
This tooling electrode is formed by conventional machining into a shape that is specific towards the
application it is employed for as well as an exact reverse from the shape to be machined in to the
workpiece. The tooling, typically machined from graphite, can be used by having an insulating fluid
such as oil or any other dielectric fluids. This shaped tooling is connected to an energy supply making
to approach the workpiece electrode, creating electrical discharges between them, which cause
erosion in the desired shape. This type of EDM is usually used for precise machining of complex 3D
parts, such as injection molding, die tooling, and other components that need exceptional accuracy.
The wire EDM, on the other hand, is an electrical discharge machine that uses a fine metallic wire,
usually produced from brass, which provides a cutting electrode to accurately shape intricate,
complex components from thick metal plates. The wire and workpiece are generally provided with
electricity so when the wire approaches the workpiece, electrical discharges occur between them.
These discharges remove material in the workpiece in a shape that is similar to a cutting or slicing
action. Because the wire electrode is eroding along with the workpiece, it is continuously fed in to
the workpiece from a spool to ensure uninterrupted cutting operation. The wire is fed through two

guides, typically produced from diamonds, each placed above and below the workpiece electrode.
These guides are movable on the 2-axis x-y plane and are CNC controlled for cutting. The cutting
operation occurs on the workpiece that's completely immersed inside a dielectric fluid bath,
normally de-ionized water, which is used as a coolant and also to flush away the removed material.
This machining process is used to cut complex and complicated 2D shapes on thick metal parts,
especially aspects of hard and exotic metals such as Inconel and titanium. Some components
commonly machined using wire EDMs are stripper plates, custom gears, and other parts that should
be intricately cut out. However, the arrival of upper guides and multi-axis freedom of movement
within the newer wire EDMs, allows these machines to chop intricate tapers and transitional shapes
as well.