Regardless of the root cause, the question concerns acceptability.  To 
clarify this specific condition in terms of conformance, the committee 
added figure 311b to the IPC-A-600H draft that John sent out for ballot 
yesterday .  In this case, the crack is in the B Zone (or overlaps the A 
and B zones) and is greater than .0031 in length.  It is therefore a 
rejectable condition as presented.  If it is related to grinding, then a 
more careful sample preparation will be able to produce sections that do 
not exhibit this condition.

        Phil






Denise Chevalier <[log in to unmask]> 
Sent by: IPC-600-6012 <[log in to unmask]>
01/29/2010 09:19 AM
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"(Combined Forum of D-33a and 7-31a Subcommittees)" <[log in to unmask]>


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Re: [IPC-600-6012] Bundle Crack in Microsection






Historically this has been termed as measling or crazing and has been
evaluated from the surface not from micro sections, see section 2.3 of
IPC-600 for photos and criteria.  Lately we have had some customers that
are rejecting for this condition when seen in the sections (terming as
bundle cracks).  Think that an open discussion would be of value - would
also like to see if there is any data out there that would contradict
the current requirement.

Denise

-----Original Message-----
From: IPC-600-6012 [mailto:[log in to unmask]] On Behalf Of Jose A
Rios
Sent: Thursday, January 28, 2010 9:09 PM
To: [log in to unmask]
Subject: Re: [IPC-600-6012] Bundle Crack in Microsection

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]> 
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01/28/2010 07:35 PM
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[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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