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Subject:
From:
"Stadem, Richard D." <[log in to unmask]>
Reply To:
TechNet E-Mail Forum <[log in to unmask]>, Stadem, Richard D.
Date:
Tue, 9 Apr 2013 18:14:05 +0000
Content-Type:
text/plain
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text/plain (136 lines)
Not really. 

-----Original Message-----
From: TechNet [mailto:[log in to unmask]] On Behalf Of Reuven Rokah
Sent: Tuesday, April 09, 2013 1:12 PM
To: [log in to unmask]
Subject: Re: [TN] Pakeout and PCB Separators

Baking in Vacuum oven = less pads oxidation and faster drying


On Tue, Apr 9, 2013 at 9:00 PM, Glidden, Kevin
<[log in to unmask]>wrote:

> Someone in Technet not long ago posted up an excellent little write up 
> from  Gordon Davy about water vapor and drying.  I've attached it to 
> Phil and Bob.
>
> It contends vacuum ovens do nothing to increase drying rate.
>
> Drying is a function of temperature and delta between concentration of 
> water in the middle versus at the surface.
>
> I presume, like any drying, the greater the surface area exposed the 
> faster the drying.  I would place the PCBs (as much as possible) 
> directly on racks or in card holders (on edge).
>
> -----Original Message-----
> From: Nutting, Phil [mailto:[log in to unmask]]
> Sent: Tuesday, April 09, 2013 1:01 PM
> To: [log in to unmask]
> Subject: Re: [TN] Pakeout and PCB Separators
>
> Robert,
>
> How about placing them in a vacuum chamber.  That would release all 
> the moisture and definitely if you could add a little heat.  I would 
> envision separating the boards with a mesh and spacer to allow the 
> moisture to fully escape.  Placing a paper towel between layers might 
> not let all the moisture escape.
>
> But then this is just my opinion.
>
> Phil Nutting
>
> -----Original Message-----
> From: TechNet [mailto:[log in to unmask]] On Behalf Of Robert Kondner
> Sent: Tuesday, April 09, 2013 12:54 PM
> To: [log in to unmask]
> Subject: [TN] Pakeout and PCB Separators
>
> Hi,
>
>
>
> Does anyone know if separators of some type between PCBs can reduce 
> bake out time?
>
>
>
> If I have a stack of PCBs, and I place something like paper towels 
> between PCBs, can the bake out time be reduced? I would imagine the 
> diffusion rates of moisture in the paper towel material would be much 
> higher than in solid PCB laminate. But, that is just a guess. Could be perfect hog wash.
>
>
>
> My problem is not with PCBs but with 30 mil sheets of plastic that 
> feed a thermoforming process.  I am using PETG but I still see small 
> bubbles in the material after forming. I tried a short bake out, and 
> it helps, but I cannot heat very high as the 30 mil plastic sheets 
> will easily deform. I need to lay them flat, heat gently, and still 
> try to removed moisture. I was wondering what the best way to separate 
> sheets and allow drying might be.
>
>
>
> Any Ideas?
>
>
>
> Thanks,
>
> Bob K.
>
>
>
>
>
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-- 

Best Regards,

*Reuven Rokah*

Mobile: 972-52-6012018
Tel:        972-3-9360688
Fax:          076-5100674
 <http://www.rokah-technologies.com/>[log in to unmask]
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**
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