EDM Types and Terms
EDM Types
-
is an EDM method that uses rotating electrodes to erode a revolving
workpiece, creating different workpiece shapes by blending the comparative
locations and angular velocities of the workpiece and the electrode.
- uses electrical energy to shape and form metal parts.
- uses a revolving electrically conductive wheel
as the electrode tool for electrical discharge erosion. EDG
is an alternative method for sharpening diamond and carbide tipped
cutting tools, reducing the extreme cost of diamond grinding
wheels.
- is a precise process that uses electrical energy to shape metal parts.
- use a tool electrode to gradually
impress a mirror image of the electrode onto a workpiece.
- is a miniature ram type machine that usually
uses a diamond V-groove to spin the tool electrode up to 10,000 rpm.
Electrode diameters as low as five microns are possible for the production
of micro-holes and other shapes in thin, electrically conductive materials.
- use a tungsten wire electrode that has a diameter as
small as 10µm to machine parts from .1 to 1 mm in size; the size
of these parts makes it impossible to form them through normal semiconductor
processes. These machines use a specially designed wire movement system,
spark generator and monitoring system able to analyze and control extremely
low energy levels.
- removes metal with rapid electrical discharges.
- uses electrical discharges to create microscopic holes.
-
is a common EDM process that removes material with a wire electrode
moving longitudinally through the workpiece. A CNC machine with special
software maintains the movement of the wire electrode relative to the
workpiece.
EDM Terms
- A mechanically altered zone on a metal surface that is created
by the EDM process.
- An uncut block of graphite
provided by a manufacturer.
- Slang term for the EDM process.
- An electrical unit
that stores electricity.
- Dielectric fluid
that is pumped through the workpiece or electrode for flushing purposes.
- Small holes on the
workpiece surface left over from the EDM sparks, also referred to as pits.
- A non-conductive
liquid that fills the space between the electrode workpiece and insulates
it until the needed space and voltage are reached. At that point, the
fluid ionizes, becoming an electrical conductor, and causes the current
or spark to flow to the workpiece; it also cools the material and flushes
away the particles produced by the spark.
-
The difference in size between the electrode and the size of the crater
the electrode makes.
- The spark in the
electrical discharge machining process.
- An apparatus initiated
by electricity that helps accurately locate the workpiece in relation
to the electrode. When any part of a workpiece comes to within about 0.0001
inches of any position alongside the electrode, a buzzer or signal light
will alert the operator.
- The tool used in
the EDM procedure, which must be made from an electrically conductive
material. The shape and form of the electrode is a mirror of the completed
shape desired in the workpiece with dimensional compensation for the
overcut.
- The elimination of
material through electrical discharge machining.
- The surface texture
in the EDM process, usually expressed as min Ra (U.S.).
- The last cut done
on a workpiece. The finer the finish preferred, the more time the finish
cut will take, so the rough cuts should be planned to leave just the material
the finish cut will remove in order to attain both the final size and
finish needed.
- The forcing of dielectric
fluid through the gap for the removal of detritus resulting from EDM.
- A measurement
of the voltage at two different points in one complete cycle. The open
gap voltage is the voltage read across the electrode and workpiece space
prior to the spark; the working gap voltage is read across the space as
the spark current discharges.
- One of four types
of carbon, used for electrode material because of its high resistance
to heat. Graphite is the most common electrode material and the simplest
to machine.
- The
layer below the recast layer. Its metal properties change due to the increased
heat exposure.
- The time between
the sparks in the EDM process.
- The variation between
the size of the electrode and the size of the cavity since an EDM crater
is always bigger than the electrode machining it. There are two different
types of overcut to take into consideration: total overcut, also known
as diametrical overcut (the most common), or overcut per side.
- The highest amount
of current that is available from every pulse of the power supply.
- A layer that
results from melted metal solidifying on the surface of the workpiece.
- An
EDM method that eliminates the most material in the least amount of
time.
- The electrical discharge between two conductors.
- The space between
the workpiece and the electrode at the point of discharge.
- The energy
that is contained in each spark.
- Comparative
smoothness or coarseness of a machined workpiece surface, typically
measured in min Ra in the U.S.
- Erosion the electrode
undergoes during the EDM process.
- Any metal part to
which an electrical discharge machining process is applied.