TECHNET Archives

September 2011

TechNet@IPC.ORG

Options: Use Monospaced Font
Show Text Part by Default
Show All Mail Headers

Message: [<< First] [< Prev] [Next >] [Last >>]
Topic: [<< First] [< Prev] [Next >] [Last >>]
Author: [<< First] [< Prev] [Next >] [Last >>]

Print Reply
Subject:
From:
Ian Hanna <[log in to unmask]>
Reply To:
TechNet E-Mail Forum <[log in to unmask]>, Ian Hanna <[log in to unmask]>
Date:
Thu, 29 Sep 2011 14:20:06 -0400
Content-Type:
text/plain
Parts/Attachments:
text/plain (211 lines)
glass style / grain orientation / cross ply lamination?

copper thieving is a good one -- as is the base material Tg/Laminate 
vendor

ian




From:
Phil Bavaro <[log in to unmask]>
To:
<[log in to unmask]>
Date:
29/09/2011 02:04 PM
Subject:
Re: [TN] Board question
Sent by:
TechNet <[log in to unmask]>



Does it violate the spec for twist after the first reflow?  Does it
matter which side is run first?

Internal layer thieving can cause this.  Typically every supplier does
their thieving differently. 

Does the panel have outside rails? 

Ask the supplier for their fab gerber used to actually make the panel.
Usually since rails get discarded throw away piece, the board suppliers
take liberties and modify the rail conductor fill to optimize their
plating processes.  You may see the outside conductors as identical but
I have always noticed the thieving in panel rails vary between suppliers
since it is not defined as part of the original pwb gerber.

I am also not sure that you ran the two different supplier panels side
by side through the oven at the same time but such a check would be good
to do if it has been a long time since the "good" supplier boards have
been run.

Joyce also has the right idea....sometimes Tg is different if it is not
a hard call out.

-----Original Message-----
From: TechNet [mailto:[log in to unmask]] On Behalf Of David D. Hillman
Sent: Thursday, September 29, 2011 10:54 AM
To: [log in to unmask]
Subject: Re: [TN] Board question

Hi Vlad - one other thing to check - is the pwb stack up "balanced"? Are

all of the layers (both the dielectric and the copper) symmetrical with 
respect to the board thickness midpoint? Are you sure all of the 
thicknesses are equal?

Dave Hillman 
Rockwell Collins
[log in to unmask]



"Vladimir Igoshev. PhD" <[log in to unmask]> 
Sent by: TechNet <[log in to unmask]>
09/29/2011 11:49 AM
Please respond to
TechNet E-Mail Forum <[log in to unmask]>; Please respond to
"Vladimir Igoshev. PhD" <[log in to unmask]>


To
<[log in to unmask]>
cc

Subject
[TN] Board question






Hi TechNetters,

I have a question for board gurus, as I'm almost lost.

Here is a story. A panel of four simple 4 layers FR4 twists after
going through the first side re-flow and flatten out after the second
side is re-flowed.   It does the same thing with and without the
components placed.

The panels are from  new vendor and the old ones had never exhibited
the problem. What confused me is that both boards (from both of the
vendors) were built identically: dielectric layers and  Cu
layers are look identical thickness- wise.

There are no signs of resin recession or delamination in
cross-sections which could have pointed out at incomplete curing.

Glass bundles look also identical.

What else it could be?

Any suggestions are deeply appreciated.
-- 
Best regards,

Vladimir Igoshev. PhD 
mailto:[log in to unmask]

SENTEC Testing Laboratory Inc.
11 Canadian Road, Unit 7.
Scarborough, ON M1R 5G1
Tel: (416) 899-1882
Fax: (905) 882-8812
www.sentec.ca


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

---------------------------------------------------
Technet Mail List provided as a service by IPC using LISTSERV 16.0
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
For additional information, or contact Keach Sasamori at [log in to unmask]
or 
847-615-7100 ext.2815
-----------------------------------------------------



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

---------------------------------------------------
Technet Mail List provided as a service by IPC using LISTSERV 16.0
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
For additional information, or contact Keach Sasamori at [log in to unmask]
or 847-615-7100 ext.2815
-----------------------------------------------------

------------------------------------------------------------------------------
This message and any attachments are solely for the use of the addressee 
and may contain L-3 proprietary information that may also be defined as 
USG export controlled technical data. If you are not the intended 
recipient, any disclosure, use or distribution of its content is 
prohibited. Please notify the sender by reply e-mail and immediately 
delete this message and any attachments.




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

---------------------------------------------------
Technet Mail List provided as a service by IPC using LISTSERV 16.0
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
For additional information, or contact Keach Sasamori at [log in to unmask] or 
847-615-7100 ext.2815
-----------------------------------------------------



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

---------------------------------------------------
Technet Mail List provided as a service by IPC using LISTSERV 16.0
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
For additional information, or contact Keach Sasamori at [log in to unmask] or 847-615-7100 ext.2815
-----------------------------------------------------

ATOM RSS1 RSS2