Ryan,
There are some good review articles: (1) SMT,Feb,1998, p84,"A Conformal
Coatings Selection Guide". and (2) NASA associated, (see enclosed first
page)http://misspiggy.gsfc.nasa.gov/ctre/hq/eee-links/vol-02/no-03/eee2-3r.h
tm
Hopes this helps.
Richard Haynes
609-497-4584
=================================================================
EEE Lin" Vol. 2, No. 3
Page 1 of 7
CONFORMAL COATINGS AN OVERVIEW OF PROCESSES AND
REMOVAL METHODS
Robert Cummings
[log in to unmask]
(301) 286-4011
Nitin Parekh
Nitin.B.Parekh. [log in to unmask]
(301) 731-8677
NASA Parts and Packaging Program
Goddard Space Flight Center
1.0 Abstract
This report sunnnarizes a literature survey of conformal coating technology
including conformal coating application and removal processes, commercially
available equipment, suppliers, current developments and a bibliography.
2.0 Introduction
Confon-nal coatings are thin layers of synthetic resins or polymers which
are applied to electronic devices for protection against a variety of
environmental, mechanical, electrical and chemical problems such as:
Humidity and moisture
Contamination
Stress, mechanical shock, vibration and then-nal cycling
Corrosion
While most conformal coatings are mostly used on populated printed wiring
boards (PWBs), they are also used to protect components such as transistors,
diodes, rectifiers, resistors, integrated circuits (ICs) and hybrid circuits
including multi-chip modules (MCMS) and chip on board (COB). The
development of conformal coating technology was fostered to a large degree
by the requirements of military and aerospace industries.
Recent environmental regulations such as the Montreal Protocol and Clean Air
Act have had a significant impact on both coating materials and application
methods, particularly with regard to control of volatile organic compounds
(VOCS) and ozone depleting chlorofluorocarbon (CFC) compounds. VOCs are the
primary concern, as they react in the atmosphere to form ground level ozone
(or smog). CFCs have been found to deplete earth's protective ozone layer
in the upper stratosphere. Both VOCs and CFCs have been extensively used as
solvent carriers. Manufacturers and suppliers of conformal coating
materials have responded by developing nonsolvent based coatings and
environmentally acceptable methods of application, curing and removal.
The purpose of this study is to provide the background information from the
literature survey of conformal coating technology
including application and removal processes, their process characteristics,
equipment and material suppliers and future trends.
3.0 Conformal Coating Technology
3.1 Types of Conformal Coating. Conformal coatings are generally classified
according to the molecular structure of their polymer backbone. There are
five basic types of conformal coatings:
Acrylic (Type AR)
Epoxy (Type ER)
Silicone (Type SR)
Parylene (Type XY)
http://misspiggy.gsfc.nasa.gov/ctre/hq/eee-links/vol-02/no-03/eee2-3r.htm
11/4/98
-----Original Message-----
From: Ryan Jennens <[log in to unmask]>
To: [log in to unmask] <[log in to unmask]>
Date: Thursday, November 05, 1998 3:37 PM
Subject: [TN] Conformal Coatings
>Howdy all!
>
>Has anybody had particularly good luck with a certain conformal coating?
If
>the response involves endorsing a brand name, please contact me at
>[log in to unmask] What is the best way to apply them? The
>board will be aboard an ambulance. Is there a particularly good type to
use
>for this?
>
>Ryan Jennens
>
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