I have a paper, which I received from Charles Leech of Altos Engineering in
March this year, about their low temperature alternative to high temp
drying. The paper was later published in SMT Express, but can send copies
off-line to anyone who's interested.
Peter
Guy Ramsey <[log in to unmask]> 09/12/2002 09:20 PM
Sent by: TechNet <[log in to unmask]>
Please respond to "TechNet E-Mail Forum."; Please respond to Guy Ramsey
To: [log in to unmask]
cc: (bcc: DUNCAN Peter/Asst Prin Engr/ST Aero/ST Group)
Subject: Re: [TN] Vacuum
Sorry, I couldn't follow up on this thread last week. And I wish I had hard
data to support my statement. Steve had it right. I am aware that some
companies are combining heat with vacuum to reduce temperature demands for
resetting Moisture Sensitive Devices. One of the Intersil link that Steve
provided last week contained equations for absorption and desorption. These
do not include pressure (which changes the boiling point). I have not been
able to find any work that includes this variable. I did go home one
evening and dig out an old college physics text. The whole thing is a lot
more complex than would first appear.
I don't think there is a serious danger posed to components unless you
"significantly" exceed the boiling point of water at a given pressure. But
what is "significant"? I can't put my finger on it. J-STD-033A has bake-out
temps of 125 degrees C for users, and 150 degrees C for supplier bake prior
to Dry Pak. Does that mean that bake out at 50 degrees C above the boiling
point of water at 0.2 bar (about 12,000 meters altitude)? I don't think so.
-----Original Message-----
From: TechNet [mailto:[log in to unmask]] On Behalf Of Mary Jane Chism
Sent: Friday, December 06, 2002 2:12 PM
To: [log in to unmask]
Subject: Re: [TN] Vacuum
Guy,
I am gathering information of the rules and regulations of MSD (Moisture
Sensitive Devices). I am in the process of developing a training class for
MSDs. Please explain how vacuum would damage the device. Are you talking
of a physical aspect of damage, esd damage, etc.? Apparently, I need to
learn more about these before I teach the class. Thanks.
Mary Jane Chism
Technical Trainer
Kimball Electronics Group
-----Original Message-----
From: Guy Ramsey [mailto:[log in to unmask]]
Sent: Friday, December 06, 2002 1:39 PM
To: [log in to unmask]
Subject: Re: [TN] Vacuum
Yes.
Moisture sensitive components can be damaged by vacuum.
> -----Original Message-----
> From: TechNet [mailto:[log in to unmask]] On Behalf Of Stolar, Paul W
> Sent: Friday, December 06, 2002 11:33 AM
> To: [log in to unmask]
> Subject: [TN] Vacuum
>
>
> Has anyone ever heard of vacuum damaging components?
>
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