| Electropolish
GENERAL
Electropolishing is a process by witch metal is cleaned
and polished in a
special electro-chemical solution. An electric current
passes through a
chemical bath dissolving a small amount of a smear
metal from the surface of the
part, thus leaving a smooth, shiny finish. During the
process, the current
density is greatest on the outside corners and edges
of the part, so those areas
are made especially smooth.
The difference between electropolishing and plating
is that instead of adding a
coating of metal to a part, electropolishing removes
metal from the part's
surface.
The process of electropolishing has proved useful
on a wide variety of metals,
principally stainless steel, brass, aluminum and copper.
Other high grade
steels also respond well to the process.
PHYSICAL APPEARANCE IMPROVED
Electropolishing's chief function is to improve parts
cosmetically. It cleans,
polished and brightens stainless steel in a way that
no other process can. The
results are easily visible to the naked eye when comparing
parts before and
after electropolishing.
Another big advantage of electropolishing is that
it removes small burrs from
the surface of a part. Because there is no vibration
or tumbling involved, as
in mass deburring, there is no chance for damage to
the parts. Electropolishing
makes extra finishing operations unnecessary so the
price per part is kept
lower.
CORROSION PROTECTION
Although stainless steel is known primarily for its
excellent resistance to
corrosion, it will still corrode under conditions where
impurities are left on
the surface of the metal. Electropolishing helps eliminate
this problem by
dissolving a minute layer of metal from the part's
surface. The surface is left
brighter, passivated and protected from rust.
OTHER APPLICATIONS
Electropolishing is not right for every part. Consultation
with one of the
engineers should precede any new application.
There are some parts such as food processing and handling
equipment which are
especially suited for electropolishing and its advantages.
Electropolishing
removes harmful impurities from the surfaces of such
parts.
Spring's and delicate stampings, because they are
subjected to repeated stress.
Have a tendency to crack or wear out prematurely. Electropolishing
helps to
protect the lives of these parts by removing surface
defects which contribute to
part failure.
Gears and splines often grow during heat treating
and electropolishing reduces
them to their original size, thus salvaging the parts.
Parts requiring better micro finishes, especially
intricate parts, have their
surfaces greatly improved through electropolishing.
As a result, friction,
leakage and wear problems are eliminated.
ADVANTAGES OVER OTHER FINISHING METHODS
Other finishing and polishing methods present problems
for some parts,
especially those that are extremely delicate or difficult
to polish. Such parts
tend to get caught on polishing and buffing wells,
often resulting
in bending or breakage.
REASONS TO SPECIFY ELECTROPOLISHING
- Brightens, cleans and polishes metal surfaces
- Removes fine burrs without damaging parts
- Removes smear metal from part surfaces
- Reduces minute scratches and imperfections
- Removes impurities which can cause corrosion in
stainless steel
- Improves micro finish surfaces on intricate
parts
- Smooths parts so that their mating part
will wear better
- Uncovers hidden defects
- Removes surface defects which can cause
springs and delicate stampings to
fail prematurely
- Reduces oversized gears and splines
so that they meet their original
tolerances
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