techniques can pull out particles, producing a severely
be free of defects such as cracks, chips, blisters or
pitted surface or heat checking. It is essential that the
sprayed particles be cleanly sheared and not pulled from
that bleed out through the coating, pits exposing the
the surface by the finishing operation.
undercoat or substrate, and coating separation. The item
will be checked for correct dimensions.
Generally, wet grinding is better than dry grinding
if you use the proper wheel. Use wheels with coarse
grain and low bond strength to grind sprayed coatings;
CONTACT ELECTROPLATING
this prevents loading the wheel. When you use a
Contact (brush-on) electroplating is also called
coolant, try to get one with a rust inhibitor and keep it
contact plating. It is a method used to deposit metal from
clean and free of foreign matter.
concentrated electrolyte solutions without the use of
Always consult and follow the coating manu-
immersion tanks. The solution is held in an absorbent
facturer's finishing recommendations when you select
material attached to the anode lead of a dc power pack
the finishing technique, including the proper tool, feeds,
The cathode lead of the power pack is connected to the
workpiece to provide the ground and complete the
and speeds.
plating circuit. Electroplating deposits metal when the
absorbent material on the anode contacts the work area.
QUALITY ASSURANCE
Constant motion between the anode and the work is
required to produce high-quality, uniform deposits.
In-process inspection of each sprayed component
Contact electroplating can be used effectively on
shall assure, as a minimum, verification of the
small to medium size areas to perform the same
anchor-tooth prepared surface with a profile tape test;
functions as bath plating. Some examples are corrosion
protection, wear resistance, lower electrical contact
chips, pits, or coating separation are present before or
during spraying; coating thickness per pass conforms to
parts. This process is not recommended to replace bath
the procedure, if this is an essential element; and the
plating. However, electroplating is superior to bath
coating manufacturer's recommended temperature
plating in some situations, most of which are in the
range is maintained.
following list:
As a minimum, the end item inspection of sprayed
coating will include a visual examination. The finished
The equipment is portable; plating can often be
coating, when examined with a 10X magnification, will
done at the job site.
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