Phil,
I don't have charts of heating printed circuit boards to diff temperatures,
but you might get some idea from looking at the heating charts you can get
from component suppliers who are concerned about pop-corning. I seem to
recall seeing a chart that talked about heating at 125C, 80C(?) and a lower
temperature.
Also, as a general rule, chemists will tell you that a 4 Celsius degree rise
in temperature will accelerate a reaction by a factor of ten. So if you
boards can dry in 24 hours at 100 C, then at 20 C they could take... well we
will be long gone. And this does not take into consideration the effect of
temperature on the diffusion of moisture from the board or the activation
energy needed to actually get the "reaction" (water leaving the board
material after breaking van der Waals attractions) started.
Finally, you did not say whether you were concerned about surface moisture
or embedded moisture.
Personally, I would recommend heating, as high as you can, without causing
significant oxidation or other nasty things.
regards,
Bev Christian
-----Original Message-----
From: Phil Nutting [mailto:[log in to unmask]]
Sent: Wednesday, December 06, 2000 8:23 AM
To: [log in to unmask]
Subject: Re: [TN] Dry Nitrogen Storage Cabinets
OK guys. This looks like a really cool system. I'm interested in possibly
using something like this to remove moisture from PWBs prior to being
installed in the oil tank of a high voltage system. Any suggestions on how
long a circuit board should be stored in this cabinet prior to sinking in
oil?
Thanks in advance,
Phil Nutting
Manufacturing Engineer
Kaiser Systems, Inc.
-----Original Message-----
From: Brad L. Matthies [mailto:[log in to unmask]]
Sent: Tuesday, December 05, 2000 5:42 PM
To: [log in to unmask]
Subject: Re: [TN] Dry Nitrogen Storage Cabinets
I concure. We have one of these units in our facility and they are well
worth the investment.
bbarr wrote:
> As an alternative to nitrogen cabinets, you may want to consider a McDry
> desiccant cabinet. Mine keeps the internal RH at 4% without heat or
> nitrogen. They are distributed by Seika Machinery in Torrence, CA.,
> 310-540-7310, www.seikausa.com.
> Many sizes are available.
>
> Bob
>
> Robert Barr
> Manufacturing Engineering
> Formation, Inc.
> Voice: 856-234-5020 x3035
> Fax: 856-234-6679
> email: [log in to unmask]
>
> -----Original Message-----
> From: TechNet [mailto:[log in to unmask]]On Behalf Of John Maxwell
> Sent: Tuesday, December 05, 2000 9:21 AM
> To: [log in to unmask]
> Subject: [TN] Dry Nitrogen Storage Cabinets
>
> I saw a while back listings of dry nitrogen storage cabinets, stored it on
> one of my computers and now I am away from that one for some time and need
> that information. Could some kind soul please e-mail off line who some of
> the manufacturers were.
>
> Thanks,
>
> John Maxwell
>
>
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