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Description / Abstract:
ABSTRACT
There is a growing need for a method of evaluating the
solderability retention capability of printed circuit parts during
inventory storage. These circuit parts, including components,
connectors, sockets and printed wiring boards are usually joined
together by soldering, hence solderability must be preserved during
inventory storage. Without accelerated aging prior to solderability
testing, i.e. as with the current common practice, little
information is gained concerning the future solderability of such
parts.
The IPC formed a Task Group to study Accelerated Aging and
recommend a method to be used for simulating long term natural
storage. This group surveyed circuit manufacturers to determine
what was needed, studied the technical literature on accelerated
aging and determined that a suitable method is available for tin
and tin/lead alloy coatings - the predominant coating materials. In
conducting this study, the task group critically assessed the
merits of steam, damp, dry, and steam-oxygen heat aging on the
basis of published supporting documentation of test results.
The Accelerated Aging Task Group recommends, for tin and
tin/lead alloy coatings, a 20 to 24 hours steam aging of specimens
above vigorously boiling distilled water to simulate one year
natural clean environment inventory storage. This report documents
these findings.