IN THE
KNOW
What is the EDM process? (Electrical Discharge Machining)_
Electrical discharge
machining which in its simplest form is machining using an electrical spark. A
controlled electrical spark is used to erode away material that can conduct
electricity. A series of electrical discharges takes place between the two
conductors separated from each other by a film of non-conducting liquid, called
a dielectric (deionized water). The eroded material again solidifies, in the
form of micro sized spheres, in the dielectric and is flushed away by the
dielectric. Wire EDM is extremely accurate. Many machines move in increments of
40 millionths of an inch (0.000 04´´), some in 10 millionths of an inch (.000
01´´), and others even in 4 millionths of an inch (.000 004´´). Extremely fine
finishes of below 15 RMS can be produced with wire EDM. (Some machines can
produce even a mirror finish.
When is EDM Processing used?
EDM is ideal when
secondary operations are too labor intensive to justify more traditional
machining operations. EDM allows for cutting complex shapes and thin walled
configurations with out distortion.
EDM is very
suitable for materials which are considered too hard or where adhesion is a
problem for traditional machining or for materials typically machined by
grinding. Some material examples include Ring & Pinions, Connecting Rods.
EDM can replace
many types of contour grinding operations and eliminate secondary operations
such as deburring and polishing. The danger of scrapping a complex or expensive
part because of tool breakage is eliminated. It is ideal for machining dies,
tools and molds.
EDM is a no-contact
and no-force process well suited for making delicate or fragile parts that
cannot take the stress of traditional machining. It is ideal for manufacturing
pieces with walls as thin as 0.002 of an inch EDM should also be considered for
parts that have cavities with a depth to width ratio greater than 50%.
EDM should be
considered a low cost tooling option when you need short run stamping and low
volume broaching. Our standard wire EDMs can cut parts 10 inches tall with a
width and length of 11 ½ by 8 inches.
