Conformal Coatings Market
For conformal
coating, there are many different facets, from equipment and
applications to various coating forms. Conformal coating is a non-conductive
dielectric protective layer that is added to the assembly of the printed
circuit board to protect the electronic assembly from toxicity, salt spray,
moisture, fungus, dust, and corrosion caused by harsh or extreme environments.
Conformal coatings are generally used in products that are manufactured for use
in outdoor environments where heat and moisture are common. The coating also
avoids damage caused by rough handling, installation, and mechanical and
thermal stress reduction.
Why conformal coating?
The conformal coating extends the
product's life during its operation. At the same time, it helps to improve the
dielectric strength between conductors in order to make the PCB's design more
compact and small. It also acts against abrasion and solvents to protect
circuitry and components.
The coating is clearly visible as
a transparent and shiny substance after the coating process is complete. Many
coatings are rough while others have a somewhat rubbery texture. Some coatings
include a marker that, when viewed under UV light, appears greenish-white. This
marker allows for easy inspection during the development of the thoroughness of
the coating.
In the past, coatings have only
been applied as the cost to military and life/medical products, and the process
per device has been significantly higher. The advancement of materials and new
processes in recent years has made it possible to cover a wider range of items,
including a wide range of consumer electronics products. When prices continue
to fall, conformal coating for circuitry and electronic components becomes
increasingly common, specifically as these products continue to shrink in
dimension and size.
Conformal coating applications
Conformal coatings are very thin
material layers designed to protect a circuit board's surface. Such layers are
added to the circuit board or substrate and serve as a defense against harsh
elements. When the finished product comprising the printed circuit board is
exposed to a harsh environment, the conformal coating can be used. Such
environments may include heat, chemicals, moisture, or any substance that could
harm a circuit or substrates mechanics.
It is vital to understand how
rework and repair issues are affected when choosing a conformal coating
material. The need to rework or fix a conformal coating can occur due to a
variety of process/product specifications or part replacement issues at any
time after completion of an assembly. Therefore, when choosing coating
chemistry, a rework of conformal coatings needs to be addressed at the front.
The application method of coating materials is a key consideration
To apply a conformal coating,
there is not necessarily a 'best' way. The method of application chosen for a
specific assembly would depend on which existing equipment is available to the
manufacturer, the coating processes in use, taking time (the average time
period between the start of production of one device and the start of the next
one) and the design of the assembly. It encompasses those circuit areas that
need to be covered and those that should not be covered (connectors, switches,
etc.).
The 'best' method of application
will ensure that each board to be coated receives coating coverage at an
appropriate thickness on all necessary metal surfaces to protect against the
environment. These specifications can vary from board design to board design
and environment to environment and must be reviewed and verified before the
production run.
Automated Conformal Coating Equipment:
In conformal coating methods, the
selective coating will be a more recent phenomenon. Selective coating blends
the advantages of multiple methods of the coating into a single method of
coating. There are various types of applicators for coating. Spray coating is
an atomized method that can achieve a thinner film pass; however, the
applicator typically has to move more slowly if selectivity is a requirement.
The finish on the edges is a glossy or fuzzy surface.
· Conformal Coating Equipment (Dip):
Automated Dip Coating is one of
the most efficient methods of conformal coating application and is ideal for
large or small volume production. The method of dipping a circuit board in a
conformal coating material stored in a tank helps ensure complete coverage.
This also includes underneath the components and around difficult later 3D
boards, and there is no over-spray or material wastage.
· Conformal Coating Equipment (Semi-Automated):
In addition to several spray
booths, we use a variety of HVLP spray guns for our hand spray process. This
approach is suitable for small-to-medium-sized quantities. In addition, this
approach is recommended for customers with large components or a geographical
layout which does not lend itself to a programmable conformal method of
coating.
To sum up
Conformal coating began as a
simple process on electronic substrates requiring extra shielding from external
elements, with little attention being paid to performance factors beyond
adequate coverage of components. Semiconductor assemblies' increased capacity
to perform complex tasks in automotive applications, signage, traffic control,
outdoor surveillance, and mission-critical elements has boosted the demand for
conformal coating.
The reliability of the
application of the coating material is critical because system failure could
have dire consequences. New equipment and processes are in place to meet these
new technologies' conformal coating requirements. Through evaluating the item
being coated and the desired result, the coating material used, the chosen
process and the economic costs over a period of time, a smooth transition to
automated precision conformal coating can be achieved.
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