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November 2012

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From:
"Glidden, Kevin" <[log in to unmask]>
Reply To:
TechNet E-Mail Forum <[log in to unmask]>, Glidden, Kevin
Date:
Fri, 16 Nov 2012 17:52:57 +0000
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Interesting.  610 seems to offer different criteria, but criteria which I have always struggled to understand and agree with.  610 reads that both measling and crazing are externally observable, with the primary differentiator being that measling is thermally induced and crazing is mechanically induced.  But the photos don't seem to match what I have seen in reality.  I have seen instances where it is absolutely known the condition was caused by mechanical means, but the condition looks more like the photos 610 offers for measling, and I have seen solder related conditions that look more like the 610 photos for crazing.


-----Original Message-----
From: Paul Reid [mailto:[log in to unmask]] 
Sent: Friday, November 16, 2012 11:54 AM
To: [log in to unmask]
Subject: Re: [TN] Root cause for measling-crazing

Hi Victor,

In my mind they are different failure mechanisms.

Measling is small blisters that are a separation of the epoxy and the glass fibers as a group. In a cross section you can see a blister type of separation. Measling is usually found by a visual examination of the board so it is on the outer layers of the dielectric.

Crazing is a separation of the epoxy from individual glass fibers. In a cross section you can see long silver air gaps running the length of fibers viewed form the side or half moon cracks around fibers when you look at the fibers on end. Crazing is most often found in cross sections and is not visible by visual inspection. 

Both can be enhanced by mechanical stress (thermal stress). 

Sincerely,  

 

Paul Reid 

Program Coordinator  

PWB Interconnect Solutions Inc. 
235 Stafford Rd., West, Unit 103
Nepean, Ontario Canada, K2H 9C1 

613 596 4244 ext. 229  

Skype paul_reid_pwb
[log in to unmask] 

 


-----Original Message-----
From: TechNet [mailto:[log in to unmask]] On Behalf Of Victor Hernandez
Sent: November 16, 2012 11:07 AM
To: [log in to unmask]
Subject: [TN] Root cause for measling-crazing

Fellow TechNetters:

   Are the above artifact cause by the wettability of the resin to yarn,
woven glass cloth rods, interface?   Then this artifact is enhance by
mechanical stress.   I am trying to understand the terminology so that
it is not misused.

"X"

From: Hernandez, Victor G
Sent: Friday, November 16, 2012 7:14 AM
To: TechNet E-Mail Forum ([log in to unmask])
Cc: Hernandez, Victor G
Subject: Laminate, Resin recession-dry glass bundle

Fellow TechNetters:

   Can any of the gurus out there comment on the above terminology and
perhaps share a photo.   What is the worse than can occur within the
laminate with such artifacts.

"X"

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