Different types of applications require different dryness levels. For instance, electronic assemblies typically need to limit the moisture content to no more than 5000 parts per million (ppm) in order to prevent corrosion and short circuits, but optical assemblies must hold the frost point below the lowest operating temperature so that lenses and mirrors don’t fog. A frost point requirement of -40°C, which is not unusual for an optical assembly in an aerospace application, equates to a moisture content of only 125 ppm. This is 40 times drier than the typical electronic requirement.
Unfortunately, a standard packaging specification like MIL-STD-2073-1 can’t provide guidance on specific dryness levels because it doesn’t even acknowledge that different targets exist. And, if a product doesn’t fit the situation for which a specification was written, the specification’s desiccant recommendation may be useless, or, even worse, dangerous.
By contrast, Hydra2O can predict the moisture levels in an assembly for years into the future, so one can aim for — and hit — a target dryness level. This is because Hydra2O accounts for all of the factors that affect dryness levels.
For instance, the moisture-holding capacity of desiccant varies with temperature and dryness level — as shown on the standard desiccant isotherm chart below. . This information is far too complex to be taken into account with a standard packaging specification, or even hand calculations, but desiccant isotherms are included in Hydra2O’s calculations.