At 07:06 AM 6/11/2008, Paul Baine wrote:
>Hello all,
>
>We received some PCBs from a Vendor where the Via holes have an 
>incomplete annular ring.  See attached photo.

In an of itself that may not be a problem.
2 issues in play:
1) Spec compliance/acceptability
    * What class (1, 2, 3) is specified for the pwb?
2) MRB disposition: (Reliability/technical/end use performance 
requirements i.e. is it safe to use the pwb)
Breakout has little to do w/ actual PTH reliability. The mere 
presence of an innerlayer pad is the 1st order contributor to reliability.
The bigger concern is whether or not the drill breakout from the pad 
reduces drill to copper feature (i.e. trace or plane) spacing below 
acceptable minimums required to provide adequate isolation and 
prevent CAF concerns.


>We have looked at Section 2.10.3 & 2.10.4 of IPC-A-600E (we don't 
>have the most recent Revision yet) and we are not sure whether these 
>Sections of the Standard apply to via holes.
>
>Any comments?  Many thanks.
>
>Paul Baine
>Q.A. Manager
>C-Tech Ltd.
>
>---------------------------------------------------
>Technet Mail List provided as a service by IPC using LISTSERV 15.0
>To unsubscribe, send a message to [log in to unmask] with following text in
>the BODY (NOT the subject field): SIGNOFF Technet
>To temporarily halt or (re-start) delivery of Technet send e-mail to 
>[log in to unmask]: SET Technet NOMAIL or (MAIL)
>To receive ONE mailing per day of all the posts: send e-mail to 
>[log in to unmask]: SET Technet Digest
>Search the archives of previous posts at: http://listserv.ipc.org/archives
>Please visit IPC web site 
>http://www.ipc.org/contentpage.asp?Pageid=4.3.16 for additional 
>information, or contact Keach Sasamori at [log in to unmask] or 
>847-615-7100 ext.2815
>-----------------------------------------------------

---------------------------------------------------
Technet Mail List provided as a service by IPC using LISTSERV 15.0
To unsubscribe, send a message to [log in to unmask] with following text in
the BODY (NOT the subject field): SIGNOFF Technet
To temporarily halt or (re-start) delivery of Technet send e-mail to [log in to unmask]: SET Technet NOMAIL or (MAIL)
To receive ONE mailing per day of all the posts: send e-mail to [log in to unmask]: SET Technet Digest
Search the archives of previous posts at: http://listserv.ipc.org/archives
Please visit IPC web site http://www.ipc.org/contentpage.asp?Pageid=4.3.16 for additional information, or contact Keach Sasamori at [log in to unmask] or 847-615-7100 ext.2815
-----------------------------------------------------