• Predicts long-term desiccant requirements for sealed enclosures
• Quickly analyzes the effects of different materials and sealing techniques on the life of an enclosure
• Reduces the risk of product failure
• Maximizes opportunities to reduce enclosure costs
• Reduces long-term maintenance and service costs
Whether your enclosure is the outer housing of a high-tech optical assembly or the sealed container for a moisture-sensitive product, Hydra2O can accurately calculate the amount of the desiccant required to maintain a target dryness level inside your enclosure for almost any length of time. Unlike standard packaging specifications which do not account for critical factors like environmental conditions, target dryness levels, time frames, and seal characteristics, Hydra2O's calculations take a wide array of factors into account in order to generate the most accurate prediction of enclosure performance possible.
Many products and mechanisms require moisture protection in order to avoid corrosion, mold growth, and other harmful moisture effects.
Perhaps the most common and effective method of protecting a moisture-sensitive item is simply to place it inside a sealed enclosure along with a desiccant to adsorb any free moisture.
Whether a sealed enclosure is the housing for a high-tech assembly or the storage container for a moisture-sensitive product, one needs to know how well to seal the enclosure and how much desiccant is needed inside the enclosure in order to prevent moisture damage.
Existing Solutions: Standard Packaging Specifications
Standard packaging specifications such as MIL-STD-2073-1 and IPC/JEDEC J-STD-033 provide guidance on protecting moisture-sensitive materials over the short term and for specific applications. For example, the military packaging specification MIL-STD-2073-1 recommends 1.2 units of desiccant per cubic foot of air volume for metal containers, with a few refinements to account for dunnage.
Standard packaging specifications like MIL-STD-2073-1 have proven themselves over time to be good enough for specific applications. That said, these standard specifications tend to be "blunt instruments": they’re typically meant to be used only for short-term shipping and storage (usually one year or less), and they recommend a conservative amount of desiccant in order to make up for unknowns in the packaging or in the exposure conditions.
Unfortunately, moisture protection over the long term and for non-standard applications can be a complicated and difficult problem -- too difficult for a standard specification to address fully. Errors in basic assumptions can compound over time and become dangerous in the long term. Extrapolating a short-term desiccant recommendation for a long-term scenario may lead to inadequate protection if an enclosure is more permeable or leaky than the "specification enclosure".
On the opposite side of the coin, the simplified assumptions behind a standard packaging specification can also lead to over-use of desiccant. For instance, what can be done for an enclosure that is extremely well sealed, and that doesn't have enough space for the full standard desiccant recommendation? How good do the enclosure seals really need to be, and can its design be modified to improve its long-term performance?
Standard packaging specifications provide inadequate guidance for addressing these questions.
A Better Solution: Hydra2O
AGM's Hydra2O Moisture Analysis service overcomes the drawbacks of standard packaging specifications by taking into account the variables that are important to specific applications:
• Length of time over which protection is required
• Environmental exposure conditions
• Seal types and materials
• Number of seals
• Container wall permeability
• Moisture in hygroscopic materials
Set a Dryness Target -- And Then Hit It
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.
Reduce Risk and Cost
Hydra2O's flexible inputs mean that it can quickly analyze the effects of materials and sealing techniques on the life of an enclosure. Will the humidity level inside a container go out of bounds during the fourth, fifth, or even tenth year of storage? Can the cost of an optical assembly's housing be reduced by switching to an alternate seal material? Because Hydra2O accounts for all critical factors, including seal materials, the designer can reduce the risk of product failure while at the same time exploring opportunities to reduce costs.
Hydra2O can also reduce long-term maintenance and service costs. Because Hydra2O can predict a container's desiccant life with a high level of confidence, it is possible to maximize the time interval between desiccant change-outs while being confident that the enclosure contents will not be put at risk. The designer can also explore the tradeoff between the additional upfront costs of premium seals versus the long-term savings associated with reduced product maintenance.
In addition to reducing maintenance and service costs, Hydra2O can also reduce the cost and time risk associated with product performance testing. In today's world of ever shorter product development cycles, cutting product testing times can mean the difference between a product being the first-to-market or being a "me-too" product. Unfortunately, testing for moisture ingress can be a time-consuming process because it takes a long time for moisture to work its way into a well-sealed enclosure. Hydra2O can reduce product test time because it provides the correct data for getting the design right the first time around -- no repeat product testing is required.
Finally, Hydra2O can mitigate the design risk associated with uncertainty in input parameters. For example, perhaps the exact conditions in which the product will be used or stored are unknown, or there is some uncertainty in the permeability of one of the enclosure's seals. Hydra2O can quickly determine the effects of parameter variability on the performance of an enclosure and put a bound on their effects. Perhaps the uncertainty really isn’t that important -- or maybe it's critical! Either way, the designer can focus on the aspects of the enclosure design that really matter once the criticality of each parameter is known.
Do you have a difficult moisture problem? Contact AGM's Sales Department about putting Hydra2O to work for you.
Information required for a complete Hydra2O analysis*:
• Target dryness level and length of time over which protection is required
• External conditions (AR 70-38 Hot-Humid or Variable High Humidity are default options)
• Enclosure air volume
• Seal materials, cross section geometry, and length
• Material and geometry of any non-metallic enclosure walls
• Environmental conditions under which enclosure is sealed before being put into service if enclosure is not dry gas purged
• Leak down test data (starting and ending pressure, time, gas medium)
• Estimate of moisture held by materials inside enclosure when it is sealed up; if this information is not available, then information about the materials inside the enclosure
*AGM can perform a Hydra2O analysis without all of the information in this list; however, the results may lose accuracy. In many cases, AGM can estimate some missing factors or the uncertainty due to lack of information. Additionally, AGM has an extensive materials library that can make up for some lack of specific knowledge. AGM will execute a non-disclosure agreement (NDA) if required for sharing of information.