The only time that traces and/or planes near the edge along with haloing
is a problem is when the features have opposite polarity.  The OEM has
to be involved so the voltage/current implications are understood.

Randy
 
Randy Reed, CQE
Global Reliability Group, North America
Merix Corporation
[log in to unmask]
 
503.992.4421-direct  l   503.545.0150-cell
-----Original Message-----
From: IPC-600-6012 [mailto:[log in to unmask]] On Behalf Of Gandhi,
Mahendra S (AS)
Sent: Wednesday, December 09, 2009 4:07 PM
To: [log in to unmask]
Subject: Re: [IPC-600-6012] FAB: Acceptability of Haloing

-----Original Message-----
From: IPC-600-6012 [mailto:[log in to unmask]] On Behalf Of Jack Olson
Sent: Wednesday, December 09, 2009 4:05 PM
To: [log in to unmask]
Subject: Re: [IPC-600-6012] FAB: Acceptability of Haloing

but people are putting planes 4-5 mils from the board edge now.
Is 2mil of haloing really drastic enough to review?[(M.Gandhi)]  - No

Or from the other side of the coin, any fabricator who sees that
a designer has put conductors that close should immediately put
the job "ON HOLD" for review until implications are
discussed?[(M.Gandhi)]  - yes and get a waiver prior to fabrication.

I'm not disagreeing with you, but that's the problem...

Jack

On Wed, Dec 9, 2009 at 5:55 PM, Gandhi, Mahendra S (AS) <
[log in to unmask]> wrote:

> All Haloing condition must be reviewed with electrical design
activities
> to make a decision of acceptance when it is over 50% from edge to
> conductor.
>
> Mahendra
>
> -----Original Message-----
> From: IPC-600-6012 [mailto:[log in to unmask]] On Behalf Of Jack
Olson
> Sent: Wednesday, December 09, 2009 2:24 PM
> To: [log in to unmask]
> Subject: [IPC-600-6012] FAB: Acceptability of Haloing
>
> Fabricators,
>
> This is an opportunity to influence the acceptability of your product!
>
> The IPC Standards Development Committee is working on the next
> revision to IPC-A-600 (Acceptability of Printed Boards) which is a
> visual reference companion to IPC-6012.
>
> One of the items we are currently discussing is the acceptability of
> haloing along the board edge. Here is a link to where we stand now:
>
> http://frontdoor.biz/PCBportal/IPC-A-600H213.jpg
>
> The problem is, if the designer violates the recommendation in the
> current IPC-2221 design guideline and puts traces or planes too close
> to the board outline, with the current wording of "whichever is less"
> your boards can be considered rejectable with even a very small
> amount of haloing. Even intentional features like edge fingers can
> make your boards rejectable.
>
> We aren't sure if we should reword this (and if so, how?)
>
> So the ball is in your court (because unless there is a logical
> consensus
> we probably won't change it).
> I'll compile and submit any responses to the next committee meeting.
>
> Jack (aka "the new guy")
>