Baking to Remove Moisture in Devices
Moisture Sensitive Devices
To avoid issues with moisture sensitive devices (MSD) in electronics it is recommended to store these devices in a controlled environment like a Dry Storage Cabinet or to reseal them following the package guidance of the device and level of sensitivity to moisture. The IPC/JEDEC standards around these are quite complex and you need to have controls in place to monitor the Floor Life (the time they have been exposed to ambient air). Once the Floor Life has been exceeded it will be necessary to bake these parts (time and temperature according to the standard used) in order to remove the moisture safely and to reset the Floor Life.
The Sahara range of Forced Ventilation Ovens were developed for this application and can safely process devices at both low temperature and high temperature bake programmes. For auditing purposes the PC software can log this process and provide evidence of baking time and temperature.
Dry Packaging – Moisture Barrier Bags
Once dried you can repackage the components in Dry Packaging, Moisture Barrier Bags (MBB), following the required standards. A Vacuum Heat Sealer can then be used to remove excess air and a desiccant added to ensure any remaining moisture in the air is absorbed. Using a HIC (Humidity Indicator Card) placed inside the bag will then confirm the maximum relative humidity level on opening.
Removing Moisture Prior to Rework of a Assembled Board
If you intend to rework, repair or carry out any high temperature thermal processing on an assembled PCB you should consider the risk of trapped moisture in the components and PCB assembly. Subjecting the board to rapid heating can cause the moisture to create large pressures with the layers of the package, leading to delamination and popcorning.
The Sahara baking ovens can be used to safely remove the moisture, prior to rework ensuring you don’t create more problems within the assembly.