Hi Victor-

Sounds ominous.

Delamination can be caused by a variety of issues, as you've mentioned.
Careful examination of the damage usually reveals the cause.

Where is the separation? It will either be at a metal interface (most often
a plane), a preg/core interface, a preg/preg interface, or within a flaw in
a preg or core. The metal interface is the most common, with causes such as
inadequate foil preparation for adhesion or too much moisture in the board
before putting it through reflow. 

Preg/core and preg/preg failures can indicate improper PCB lamination
process at the fabricator.

Intra-laminate failure can be due to flaws within the laminate cores or
prepregs as purchased from the laminate supplier.

If there is charring on what you're looking at, then you need to develop a
hypothesis as to the cause. If the heat originated with conductors, it
should be pretty obvious, with charcoal around the heat source. If the
overall laminate is evenly baked and brittle, then it was probably heated
from the outside, such as the solder float test or other tortures. Laminate
can also be over-baked by a lamination cycle that is way too long, or too
many times through the lamination press (for complex via structures, such as
sequential build-up).

Wayne

-----Original Message-----
From: TechNet [mailto:[log in to unmask]] On Behalf Of Victor Hernandez
Sent: Friday, January 09, 2015 11:13 AM
To: [log in to unmask]
Subject: [TN] PWB laminate delamination

Fellow TechNetters:

   Where can I find information regarding delamination?   Are the laminate
material separation artifact of thermal excursion, solder float test, 3x or
6x, differ from that of an exothermic event in which current/heat melts the
laminate and/or heat exploded/cracking the laminate.

Victor,


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