Moisture Sensitivity Level Receiving Audit and Dry Bake Containment
Receiving verification of moisture barrier packaging and strict floor life tracking prevent reflow delamination yield losses in surface mount assembly.
Desiccant Unit
Absorption Medium
Standardized quantities of drying agents are packaged in porous pouches to absorb specific amounts of moisture from sealed volumes. This dry packet is a desiccant unit, which is defined by its ability to absorb a set quantity of water vapor under standard temperature and humidity conditions. It is used to maintain low humidity inside moisture-barrier bags.
The size of the pouch is matched to the surface area of the bag.
Dry Environment
The porous paper or cloth of the pouch allows air to pass through while keeping the mineral grains contained. This design allows the drying agent to continuous extract moisture from the enclosed space. The relative humidity is held below the critical ten percent threshold.
This low moisture level is necessary to stop the dry components from absorbing ambient humidity.
Regeneration Process
Spent drying packets can sometimes be restored by heating them to evaporate the stored moisture. This baking process must be monitored carefully to avoid damaging the outer pouch material. The heating cycle must be held at a steady temperature for several hours.
This practice allows the reuse of the materials in subsequent packaging runs.
Calculation Method
Industry standards such as those from JEDEC define equations to determine the number of drying pouches needed for a specific bag size. The formula uses the bag’s surface area, its moisture transmission rate, and the required shelf life. For example, a bag with high surface area and a long storage requirement will require multiple pouches.
This math prevents under-specifying the drying capability. Precision calculations ensure that the internal humidity remains low for the entire planned storage period without using excessive materials.