Hi Daan!

We bake our boards for 2 1/2 hours at 121 C (for FR-4) prior to a reflowing
including if it's a second try.


Hans

~~~~~~~~~~~~~~~~~~~
Hans M. Hinners
Materials (Process & Manufacturing) Engineer
Warner Robins Air Logistics Center
Avionics Production Division
Manufacturing Branch
380 Second Street, Suite 104
Building: 640, Mail Stop: LYPME
Robins AFB, GA 31098-1638
Voice: (912) 926 - 1970 Fax: (912) 926 - 7164
mailto:[log in to unmask]
http://www.robins.af.mil


-----Original Message-----
From: d. terstegge [mailto:[log in to unmask]]
Sent: Tuesday, May 16, 2000 11:00 AM
To: [log in to unmask]
Subject: [TN] Speed of moisture absorbtion


Hi Technet,

I'm currently working on a handling procedure for moisture sensitive device.
There's quite some information about this subject in the Technet-archives,
but one thing I couldn't find is how quickly a component can absorb water
from a cleaning operation. I mean, if we put our BGA-boards in our cleaning
machine (which includes about 25 minutes spraying of hot water), can we
still safely proceed with a second reflow step ?
And what if we have a paste misprint, and clean the board (with components
on one side) in our solvent-filled stencilcleaner (Alpha SC1080) ?
Hope to hear from you !

Kind regards

Daan Terstegge
SMT Centre
Signaal Communications
Unclassified mail
Personal website: http://surf.to/smtinfo

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