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August 2003

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Subject:
From:
"Dehoyos, Ramon" <[log in to unmask]>
Reply To:
TechNet E-Mail Forum.
Date:
Tue, 26 Aug 2003 13:00:46 -0700
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        Francois:
          I have been exposed to the weight charts only. I am surely
interested in knowing about the moisture diffusion models. It   sounds
interesting.
        Regards,
        Ramon


> -----Original Message-----
> From: Francois Monette [SMTP:[log in to unmask]]
> Sent: Tuesday, August 26, 2003 9:23 AM
> To:   [log in to unmask]
> Subject:      Re: [TN] Dry Cabinet
>
> Bonjour Yannick,
>
> Here are a few additional considerations relative to dry storage :
>
> Make sure that you understand exactly what kind of benefit you will get
> from
> your dry storage solution. In the contract manufacturing business, many of
> your customers will expect that you comply with the guidelines from the
> latest IPC/JEDEC standard J-STD-033A. This document contains precise rules
> on how to account for dry storage. In summary the clock of exposure time
> does not necessarily stop when previously exposed components are returned
> to
> dry storage, whether it be a dry cabinet, Nitrogen box or re-sealed dry
> bag
> with desiccant.  The actual effect of dry storage on the remanining floor
> life will vary based on the type of component (MS level), the type of dry
> storage (RH level) and the complete history of exposure and subsequent
> storage.
>
> I also suggest that you be careful when reading the marketing data
> provided
> by some of the vendors of dry storage solutions. In many cases their
> conclusions are based on experimental data using a weight gain measurement
> technique. This is not consistent with the current industry standard which
> is based on a much more accurate moisture diffusion model. I can provide
> more details and technical references if you are interested.
>
> Regards,
>
> Francois Monette
> Cogiscan Inc.
> Tel : 450-534-2644
>
>
>
>
> -----Message d'origine-----
> De : Steve Gregory [mailto:[log in to unmask]]
> Envoy=E9 : Thursday, August 21, 2003 11:19 AM
> =C0 : [log in to unmask]
> Objet : Re: [TN] Dry Cabinet
>
>
> Hi Yannick!
>
> We use the McDry cabinents here, and they work great. The humidity =
> level is
> kept around 4% RH, and that's not too bad..you know, it never gets hot =
> or
> humid here in Tulsa, Oklahoma (GRIN). Also, when I start running low on =
> beef
> jerky, I'll just throw a few slabs of beef in for a few days...(JUST
> KIDDING)
>
> You may think at first they are expensive, but when you figure the =
> costs of
> plumbing nitrogen, and the on-going expense of using the nitrogen, the =
> costs
> really aren't that bad.
>
> There's virtually no maintenance on them, as they self-regenerate the
> dessicant in them. You should send the humidity meter out annually for
> calibration, McDry will do that for you. In fact, they send you a =
> notice
> when yours is due for calibration.
>
> Camera dry boxes are kind of small, and the ones I've seen don't go =
> down to
> the low humidity levels that the dry boxes for electronics do.
>
> One good thing about desiccant cabinents, is that you can avoid baking =
> if
> the components are left in the dry box long enough. According to the =
> data,
> they will actually "de-humidify" the components bringing the absorbed
> moisture down to a level below where "pop-corning" or micro-cracking =
> can
> occur.
>
> There's two companies that I know of that make these desiccant dry =
> boxes.
> One is McDry (the ones I use), and the other is a company called Toyo
> Living. This last APEX show is the first time I've seen Toyo Living dry
> boxes. They supposedly are cheaper than McDry, and also contain heaters =
> that
> work in conjunction with the desiccant. Here's the links to both =
> companies"
>
> http://www.seikausa.com/mcdry/
> http://www.toyoliving.biz/
>
> Best regards,
>
> -Steve Gregory-
>
>
>
>
> Hi,=20
>
> we'll use the cabinet for keep our QFP dry, we use to have a moisture
> probleme right now, I don't know the level of humidity/dryness to be
> maintained, cause it's maybe depending of the component, we don't what
> something complex, jsut a standard cAbinet not to expensive...
>
> Yannick
>
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