30 | JULY 2017 www.canadianmetalworking.com
BY SUE ROBERTS
Three ingredients are key to success- ful sinker or ram electrical discharge
machining (EDM) cutting—the machine, the
electrode tooling, and the dielectric fluid.
The equipment and the electrode typically
get the most attention. The fluid, an oil
designed specifically for the process, not so
much. But it should.
When the fluid degrades, machine performance declines. Cutting speeds slow and
quality and surface finish suffer. Filling the
machine tank with a petroleum-based oil is
not a one-and-done deal.
The dielectric fluid, a critical and fundamental component of the process, estab-lishes the medium in which the machining
discharge spark energy is finely controlled,
balanced, and delivered to the workpiece.
When the workpiece and electrode are submerged in the fluid for the machining process, the fluid transforms from an insulator
to a conductive channel to deliver the high-power discharge spark energy that vaporizes
And the fluid flushes the miniscule chips
formed when the vaporized metal condenses
back to solids away from the workpiece to
clear the spark gap zone before the next
electric discharge cycle begins. To attain
and maintain optimal EDM efficiency, the
dielectric fluid characteristics need to be
clean and stable.
“Depending on your application, your standard petroleum-based fluids will probably
Dielectic fluid transforms to a conductive channel to
deliver the spark that vaporizes the metal when the
electric discharge takes place. Photo courtesy of
Dirty or degraded oils slow
machining and hurt quality
CLEAN EDM FLUIDS
PRODUC TIVIT Y