Joey,

Excellent question that comes up more and more as designers move conductors near the edge of boards and holes.  Certainly from a pure IPC-6012 perspective, the part you show violates the haloing criteria.

1. I have measured a lot of haloing and determined that the capability in the "industry" is about 10-12 mils of haloing for polyimide and about 8 mils for fr4. That includes new bits and everything else to eliminate the condition.

2. That being said, polyimide designs where any conductor is closer that 22 mils from an internal or external vertical edge and 16 mils for Fr4 must be flagged in the front end for an AABUS agreement.

3. Going forward, all of us in the 6012 committee should consider some defaults when the conductors are "close to an edge" in the new revision we are working on now.


Mike Hill
Quality Manager
DDI Virginia

++++++++++

-----Original Message-----
From: IPC-600-6012 [mailto:[log in to unmask]] On Behalf Of Jose A Rios
Sent: Thursday, December 15, 2011 12:09 AM
To: [log in to unmask]
Subject: [IPC-600-6012] haloing

wondering how others interpret the applicability of 6012c 3.3.1 (and its
6018 equivalent) with respect to haloing, for designs that have metal to the edge of a pwb, as shown below?? conductor to conductor spacing is highly compliant, distance from the solder feature to the first halo along the edge is less than 4 mils.


to me 3.3.1 has a context where metal is away from the board edge by design, unlike the attached image.....

Joey Rios
PWB & Process Quality Eng'r
Endicott Interconnect Technologies
1093 Clark St.
Endicott, NY 13760
Office: 607-755-5896

______________________________________________________________________
This email has been scanned by the Symantec Email Security.cloud service.
For more information please contact helpdesk at x2960 or [log in to unmask] ______________________________________________________________________

This communication is for use by the intended recipient(s) only and may contain information that is privileged, confidential, proprietary and exempt from disclosure under applicable law.  You are hereby notified that any dissemination, distribution, forwarding or copying hereof is strictly prohibited without the express written consent of DDi.  If you have received this communication in error or are not the intended recipient, you should destroy the message and any attachments or copies, and you are prohibited from retaining, distributing, disclosing, or using any information contained herein.  Please inform us of the erroneous delivery by return e-mail. Thank you for your cooperation.

______________________________________________________________________
This email has been scanned by the Symantec Email Security.cloud service.
For more information please contact helpdesk at x2960 or [log in to unmask] 
______________________________________________________________________