1. The SMT Storage Process
Storage systems are required to keep components and materials in good condition prior to their use in the assembly process. Often this means control over temperature and humidity levels for sensitive components. This is achieved by hot air, nitrogen or dessicant systems.
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2. Storage Applications
Storage cabinets are now required to not only store standard and odd form products and components ready for use, but to also now keep control of the environment that they store them in. Beyond standard shelving and cabinets, advanced SMT now requires humidity and temperature control.
This requirement enables open components to be stored without absorbing moisture. As a result microcracking due to moisture entrapment during reflow can be avoided. These cabinets can also eliminate the need to bake certain components. SMT reels and waffle trays can be stored in these cabinets.
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3. Storage Cabinet Types
Storage cabinets deisgned for low humidity storage come in various sizes depending on what is required of them. Small desktop cabinets are often used on a line to allow quick and easy access to readily used components.These cabinets use a number of methods to control humidity including hot air and automatically recycling dessicant systems, and can maintain humidy at down to 1% RH.
Vending style systems are also available for reel storage and consumable storage to allow better stock control and usage tracking.
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4. Troubleshooting Storage Problems
There are many solutions for efficient component storage and conditioning, however a few rules of thumb will always apply:
Oxidation..
Oxidation
of component terminals will cause solderability issues, so it is important to maintain proper shelf life discipline and to not allow components to lie around open to the atmosphere.
Microcracking/Popcorning..
This issue is now more prevalent due to the switch to Pb free soldering. The higher temperatures associated with this process make trapped moisture within components more likely to instigate cracking during reflow.
Therefore the proper use of low humidity cabinets or dessicant bags is important.
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5. Expert Advice..
Please visit individual supplier websites for further detailed information.Browse manufacturers storage equipment here
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