TECHNET Archives

April 2013

TechNet@IPC.ORG

Options: Use Monospaced Font
Show Text Part by Default
Show All Mail Headers

Message: [<< First] [< Prev] [Next >] [Last >>]
Topic: [<< First] [< Prev] [Next >] [Last >>]
Author: [<< First] [< Prev] [Next >] [Last >>]

Print Reply
Subject:
From:
Steven Creswick <[log in to unmask]>
Reply To:
TechNet E-Mail Forum <[log in to unmask]>, Steven Creswick <[log in to unmask]>
Date:
Tue, 9 Apr 2013 19:48:55 -0400
Content-Type:
text/plain
Parts/Attachments:
text/plain (142 lines)
Bob,

Cardboard is synonymous with sulfur compounds in my mind - especially the
corrugated kinds.  Just be careful with it.

Maybe some lint-free clean room wipes?

Steve C

-----Original Message-----
From: TechNet [mailto:[log in to unmask]] On Behalf Of Robert Kondner
Sent: Tuesday, April 09, 2013 6:30 PM
To: [log in to unmask]
Subject: Re: [TN] Pakeout and PCB Separators

I was thinking maybe corrugated cardboard. I will give that a try.

Bob Kondner

-----Original Message-----
From: TechNet [mailto:[log in to unmask]] On Behalf Of Stadem, Richard D.
Sent: Tuesday, April 09, 2013 2:13 PM
To: [log in to unmask]
Subject: Re: [TN] Pakeout and PCB Separators

The best method of drying sheets of plastic is to put them on
accordion-style holders that allow air to flow under the substrate to be
dried. 
Else a wire rack that will not get so hot as to leave a permanent mark in
the plastic sheet.

-----Original Message-----
From: TechNet [mailto:[log in to unmask]] On Behalf Of Glidden, Kevin
Sent: Tuesday, April 09, 2013 1:01 PM
To: [log in to unmask]
Subject: Re: [TN] Pakeout and PCB Separators

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.

 



______________________________________________________________________
This email has been scanned by the Symantec Email Security.cloud service.
For more information please contact helpdesk at x2960 or [log in to unmask]
______________________________________________________________________

______________________________________________________________________
This email has been scanned by the Symantec Email Security.cloud service.
For more information please contact helpdesk at x2960 or [log in to unmask]
______________________________________________________________________

______________________________________________________________________
This email has been scanned by the Symantec Email Security.cloud service.
For more information please contact helpdesk at x2960 or [log in to unmask]
______________________________________________________________________

______________________________________________________________________
This email has been scanned by the Symantec Email Security.cloud service.
For more information please contact helpdesk at x2960 or [log in to unmask]
______________________________________________________________________


______________________________________________________________________
This email has been scanned by the Symantec Email Security.cloud service.
For more information please contact helpdesk at x2960 or [log in to unmask]
______________________________________________________________________


______________________________________________________________________
This email has been scanned by the Symantec Email Security.cloud service.
For more information please contact helpdesk at x2960 or [log in to unmask] 
______________________________________________________________________

ATOM RSS1 RSS2