Hi Bill,

Per IPC-A-600, Par. 3.1.1. for boards class 2 and 3 the nonconforming voids
are described as "Voids in excess of 0.08 mm (0.003 in) or voids violate
minimum dielectric spacing". The same requirements are also found in
IPC-6012A Par. 3.6.2.3.

I'm in the midst of a problem that, I believe, has to do with laminate
voids. The assembled boards are failing in the field after few weeks to
several months of service!! These modules are not for high altitude
application. The voids occurred in a laminated core (so it is a laminate
supplier problem not PCBs manufacturer problem) between power and ground
layers.

Sherif,



----- Original Message -----
From: "Brown, William G" <[log in to unmask]>
To: <[log in to unmask]>
Sent: Tuesday, April 22, 2003 1:45 PM
Subject: [TN] Voids / Air Pockets in Laminates


> Hi All,
>
> Does anyone know where I can find information on air bubbles or voids
within
> completed circuit boards?  We have a group here which is concerned about
any
> voids left when the laminates are pressed together, either within or
between
> layers, and the effects they might have at high altitudes.
>
> Are there any IPC specs which state allowable values or anything like
that?
> These are boards made with IPC-4101/ 40, 41 or 42 materials.
>
> Thanks for any help!
> Bill
>
> ############################################
> William G. Brown
> Senior Electrical Engineer - PWD Engineering Support
> > xBAE  SYSTEMSx - Information & Electronic Warfare Systems
> Phone: 603-885-4930     Fax: 603-885-5435
> ############################################
>
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