isnt this crazing (or a cousin of...)  ??
i'd be interested to see the area of interest at higher mag, to see if the 
crack goes thru an actual glass fiber or not.
i've seen cracks induced by sectioning (aggressive grinding/polishing) 
where individual glass bundles are cut in half.
as to possible caf paths, couldnt measles and/or crazes act as such, yet 
neither one is rejectable.

Joey Rios
PWB & Process Quality Eng'r
Endicott Interconnect Technologies
1093 Clark St.
Endicott, NY 13760
Office: 607-755-5896



John Perry <[log in to unmask]> 
Sent by: IPC-600-6012 <[log in to unmask]>
01/28/2010 07:35 PM
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"(Combined Forum of D-33a and 7-31a Subcommittees)" <[log in to unmask]>


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Subject
[IPC-600-6012] Bundle Crack in Microsection






Hi Everyone,

We've got a request for feedback on the anomaly in the attached .ppt file 
which was detected in one bundle of glass in a coupon.  This is in the 
center of the board stack, which is a 24 layer construction.  Since it is 
in the core material it may be related to glass non-wetting of the resin 
or poor glass treatment.

I'd also like to know if this is something we can consider developing 
criteria for in the next generation of IPC-6012/A-600 when we meet in Las 
Vegas in a couple months.

Regards,

John Perry
Technical Project Manager
IPC - Association Connecting Electronics Industries(r)
3000 Lakeside Drive # 309S
Bannockburn, IL 60015-1249 USA
+1 847-597-2818 (tel)
+1 847-615-7105 (fax)
+1 847-615-7100 (Main)
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