Painting by cataphoresis
This is an immersion process that allows the
pieces to be coated with paint. It is performed by cathodic electro-deposition: the
cations (positively charged ions generated
by the dissociation of paint molecules), immersed in an aqueous solution, adhere to
the profiles creating a uniform layer.
The process involves the following phases:
1. Physical-chemical degreasing of hot-rolled parts. This removes grease, particles and other impurities present on the
surface of the profiles.
2. Rinsing.
3.Creating a nano-technological conversion layer of zirconium fluoride on the steel. It is very compact and
with few interstitial spaces. Its mission is
to provide anti-corrosive protection, decreasing exposure of the base steel to the
environment and, in turn, improve paint
adhesion.
4. Washing with deionized, demineralized. It is necessary that the surface is
clean and free of salts to facilitate maximum paint adhesion.
5.Cataphoresis bath. In the immersion,
the paint coats the entire piece, inside and outside. The profiles act as the
cathode (negative pole) and the paint as
the anode (positive pole). The interaction
with an electric field between 240 and
300 V DC for about two minutes allows
ion exchange between foreign molecules of the profile and the paint itself, en-
Ultrafilter is a component that removes
traces of badly adhered paint and creates
a smooth, even surface.
7. Polymerization of the pieces in an oven
at 356 °F for approximately 40 minutes.
PAINTED BY IMMERSION
Paint is uniformly distributed over the entire surface of the profile
PAINTED BY ELECTROSTATIC SYSTEM
Insufficiently
painted
Properly
painted
Properly
painted
Adequately
painted
Scantly painted
(Faraday effect)
BLASTING NOZZLE CENTERED ON
THE PROFILE (OP TIMUM POSITION)
A
Onset of oxidation
that occurs in this shady area is
difficult to observe
suring greater strength through a thinner coating.
6.Bathing of pieces with recirculated
ultra-filter and after wards on the exit
ramp with a spray of new ultra-filter.
