The design controls how close the conductors are to the edge and what
material is used. The results of those two inputs require the fabricator
to modify their process to compensate for the design. Often, fabrication
modifications can not provide the needed results.
Tom Kemp
Sr QAE
Rockwell Collins
319-295-1619
"Gandhi, Mahendra S (AS)" <[log in to unmask]>
Sent by: IPC-600-6012 <[log in to unmask]>
03/15/2010 10:00 PM
Please respond to
"(Combined Forum of D-33a and 7-31a Subcommittees)" <[log in to unmask]>
To
[log in to unmask]
cc
Subject
Re: [IPC-600-6012] Edges and Crazing/Haloing
I would call it as a design, material and/or fabrication combo.
Mahendra Gandhi
-----Original Message-----
From: IPC-600-6012 [mailto:[log in to unmask]] On Behalf Of Thomas E
Kemp
Sent: Monday, March 15, 2010 8:25 AM
To: [log in to unmask]
Subject: Re: [IPC-600-6012] Edges and Crazing/Haloing
With the new high temp materials we are finding haloing popping up where
we never were before. It is still a design issue.
Tom Kemp
Sr QAE
Rockwell Collins
319-295-1619
Mike Hill <[log in to unmask]>
Sent by: IPC-600-6012 <[log in to unmask]>
03/15/2010 10:09 AM
Please respond to
"(Combined Forum of D-33a and 7-31a Subcommittees)" <[log in to unmask]>
To
[log in to unmask]
cc
Subject
Re: [IPC-600-6012] Edges and Crazing/Haloing
Jim is headed in the right direction.
All of the issues I have with haloing are with polyimide material. If this
is universal, we might modify requirements by material type.
Mike Hill
Quality Manager
Colonial Circuits, Inc.
540-752-5511 x121
-----Original Message-----
From: IPC-600-6012 [mailto:[log in to unmask]] On Behalf Of Monarchio,
James
Sent: Monday, March 15, 2010 9:58 AM
To: [log in to unmask]
Subject: Re: [IPC-600-6012] Edges and Crazing/Haloing
John - this still does not resolve the issue we parked.
The design can have spacing such that no crazing, etc. is allowed. We
discussed (and parked) verbiage relating the requirement to designs that
comply with 2221.
Wendy's example may indeed be unmaunfacurable to the spec (and I agree).
In practice these issues are given a blind eye until there is an issue of
some type then parts that were acceptable yesterday are noncompliant
today. This is a bad situation for all.
I believe we should define a hard crazing allowance for product not
designed to 2221 (i.e. 10 mils)- it would be neater and cleaner as well as
getting the real issue back where it belongs - design.
Jim
-----Original Message-----
From: IPC-600-6012 [mailto:[log in to unmask]] On Behalf Of John Perry
Sent: Sunday, March 14, 2010 5:06 PM
To: [log in to unmask]
Subject: Re: [IPC-600-6012] Edges and Crazing/Haloing
Jack and All,
We used to say the following in 3.3.1, Edges, in IPC-6012B:
3.3.1 Edges - Nicks, crazing or haloing along the edge of the board, edge
of cutouts and edges of nonplated-through holes are acceptable provided
the penetration does not exceed 50% of the distance from the edge to the
nearest conductor or 2.5 mm [0.0984 in], whichever is less.
Now IPC-6012C will say the following:
3.3.1 Edges - Nicks or crazing along the edge of the printed board, edge
of cutouts and edges of non-plated holes are acceptable provided the
penetration does not exceed 50% of the distance from the edge to the
nearest conductor or 2.5 mm [0.0984 in], whichever is less. The distance
between the haloing penetration and the nearest conductive feature shall
not be less than the minimum lateral conductor spacing, or 100 µm [3,937
µin] if not specified.
Regards,
John Perry
Technical Project Manager
IPC - Association Connecting Electronics Industries®
3000 Lakeside Drive # 309S
Bannockburn, IL 60015-1249 USA
+1 847-597-2818 (tel)
+1 847-615-7105 (fax)
+1 847-615-7100 (Main)
[log in to unmask]
www.ipc.org
-----Original Message-----
From: IPC-600-6012 [mailto:[log in to unmask]] On Behalf Of Jack Olson
Sent: Friday, March 12, 2010 3:25 PM
To: Listserv IPC-600-6012
Subject: Re: [IPC-600-6012] Edges and Crazing/Haloing
The guideline for edge to hole is in IPC-2222, not IPC-2221
in IPC-2222 10.1.1 it says board edge or unplated hole to conductor
shall not be less than Table 6-1 of IPC-2221 plus .4mm
(and Table 6-1 is your minimum clearance based on voltage)
The MINIMUM from Table 6-1 (.05mm) plus .4mm works out to 17mils!
The discussion you remember was regarding IPC-2222 requirement
for haloing, and I'm not sure it was ever resolved, but I remember
we DID change some wording for the next revision.
You could get the new changes from John Perry for your own interest,
but of course it won't mean much until it is officially published.
And the haloing rule it won't help if your designers are disregarding the
clearance guideline, but I'm sure you know THAT (grin)
good luck!
Jack
On Fri, Mar 12, 2010 at 10:11 AM, Wendi Boger <[log in to unmask]>
wrote:
> Everyone,
>
>
>
> I seem to remember a discussion about Haloing of edges and non plated
> holes at one of our recent meetings. The requirement for the haloing
> to be less than 50% the distance to nearest conductor works assuming the
> design has a reasonable space from conductor to edge. I looked in
> IPC2221 but did not find a guideline for suggested minimum distance. We
> are seeing non-plated tolling holes with surface ground rings at <10mils
> hole edge to copper. Depending on the material and hole size it's
> difficult to meet the 50% rule.
>
>
>
> Is there a section in 2221 I can send the designers to so we can
> avoid this type of issue?
>
>
>
> Thanks,
>
> Wendi Boger
>
>
>
>
>
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