scope:

Moisture absorption can cause delamination or other damage in printed boards subjected to soldering heat. This test is a process control tool to determine both the bulk moisture content and moisture absorption rate of a printed board. It may be used to determine whether the specimen conforms to the monitoring level of the user's performance specification, to assist in process development, or for process control. This test may not provide accurate analytical results on all specimens, depending on the thickness of the item, the presence of copper layers or other moisture barriers within the structure, or the presence of any volatile compounds other than water. The weight of the specimen is compared before and after a bake operation. The bake is intended to remove most of the water (> 90%) from the sample, and the bake time and temperature specified herein are minimums. To improve test accuracy, or to prevent heat damage, other bake parameters may be as agreed between user and supplier (AABUS).