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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