5-2 Site Preparation
5 Environmental Requirements
Air Quality Requirements
As a rule, good air quality is as important for the reliability of your i3070 test system
as it is for your production process. Three types of airborne contaminants are
discussed below. The presence of any of these contaminants at the site will
contribute to system degradation, resulting in lower reliability and higher operating
costs.
Corrosive Contaminants
Corrosion is a complex form of material deterioration or destruction by chemical or
electrochemical reaction. The presence of corrosive contaminants (gases) in the
atmosphere is very common in industrial environments. If ignored, corrosion can
eventually degrade system performance by its effects on high impedance circuits
and low impedance interfaces. It can also deteriorate most plastics including
software storage media. The effects of corrosive contaminants are usually
accelerated at high humidities or high temperatures.
Corrosives generally cannot be filtered out of the air by normal filtration methods,
and the techniques that must be used for their removal are complex and costly. If
the source of corrosive contaminants cannot be eliminated, the system should be
installed in an enclosed environment with a fresh air supply at positive pressure.
Particulate Contaminants
Particulate contaminants (hard particles) consist of smoke, dust, hair, lint, fibers
and miscellaneous organic and inorganic materials. The presence of these
contaminants in the air can cause system degradation, especially where disk drives,
test fixtures, and low impedance interfaces are concerned. Particulate
contaminants can be filtered from the air, and appropriate filters should be included
with any air conditioning installation. Also consider installing “No Smoking” signs
in the area. Tobacco smoke is a well-known factor in fixture contact contamination.
It causes false failures leading to unnecessary DUT repairs and higher production
costs.
Viscid Contaminants
Viscid contaminants are oily or sticky airborne substances that can be deposited on
the system’s electronic and mechanical parts. Besides contributing directly to
system degradation, viscid contaminants collect and hold particulate contaminants
and make cleaning very difficult. Viscid contaminants can be removed from the air
by filtration, but the elimination of their source, if possible, is preferable.
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