MILPRF55110G
APPENDIX E
E.5.3
E.5.3 Application of test method.
a.
The inspection/test personnel shall record the specimen lot date code and manufacturer for each individual
printed wiring board. An individual printed wiring board reference chart for the test plated-through holes and
PWB contact pin locations shall be maintained for each test specimen configuration.
b.
Insert test specimen onto SERA test head and allow a minimum of 4 seconds for inert gas purging of the test
head. Ensure inert gas bubbling is occurring in the reservoir tube.
c.
Attach PWB contact pin.
d.
Attach electrical source leads.
e.
Draw borate buffer solution into test head chamber a minimum of 75 percent of chamber height. Visually
monitor test head chamber for leaks.
f.
Partially flush test head chamber to 50 percent height to dislodge any gas bubbles which could be trapped in
test hole.
g.
Input computer data for test specimen and test hole identification. Set current density at 30 µamp per
centimeter squared (plated-through hole area shall be calculated as specified in E.5.3.1), test duration at a
minimum of 400 seconds, the number of open circuit samples to be measured, and the number of systems
measurements at one reading per second. The minimum test duration may be reduced provided complete
plated-through hole reduction has been achieved.
h.
Perform SERA test to test duration completion.
i.
Remove electrical source leads.
j.
Remove PWB contact clamp.
k.
Flush borate buffer solution from test hole.
l.
Remove test specimen from SERA test head.
m. Rinse test plated-through hole with deionized water saturated cotton swab for a minimum of 3 seconds, then
rinse test plated-through hole with isopropyl alcohol saturated cotton swab for a minimum of 3 seconds.
Allow test plated-through hole to air dry. The rinsing operations may be conducted for all test holes as a one
time operation provided the rinsing operation is completed within 10 minutes of completion of the last test
hole on that individual printed wiring board specimen. Other documented rinsing operations may be used
provided their effectiveness is as good as or better than the cotton swab rinse process.
E.5.3.1
E.5.3.1 Plated-through hole area calculation. The area of plated-through holes shall be determined using:
Area = (2)(š)(R1)(H) + [(2)(š)(R22) (2)(š)(R12)]
where
H
= Printed wiring specimen thickness.
R1
= Plated-through hole radius.
R2
= O-ring internal radius.
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