Qfn vendor usually tell you what thickness of stencil to use with what size of opening. How was that recommendation compare to your design?
--------------------------
Sent using BlackBerry
----- Original Message -----
From: Roger Mack [mailto:[log in to unmask]]
Sent: Thursday, August 19, 2010 10:51 AM
To: [log in to unmask] <[log in to unmask]>
Subject: Re: [TN] Bulging solder on the sides of QFP leads
Have you measured the actual pad widths? If your design has a 20mil pitch
part with 10mil pads, you will likely have a much narrower pad at the
surface on a 3 oz. board. If your stencil design was for a 10mil pad you
may have poor gasketing and be depositting more paste than you intended
to.
Roger Mack P.Eng.
Manufacturing Specialist
Parker Hannifin Electronic Controls
Electronic Controls Division
1305 Clarence Avenue
Winnipeg, MB R3T 1T4 Canada
direct 204 453 3339 x373
[log in to unmask]
www.parker.com/ecd
Ioan Tempea <[log in to unmask]>
Sent by: TechNet <[log in to unmask]>
08-19-2010 08:34
Please respond to
TechNet E-Mail Forum <[log in to unmask]>; Please respond to
Ioan Tempea <[log in to unmask]>
To
[log in to unmask]
cc
Subject
Re: [TN] Bulging solder on the sides of QFP leads
Thanks again!
To get back a bit to Steve's observation: the boards indeed have 2 layers
of soldermask. But it has 3oz of Cu on all the layers.
Would it be necessary to have 2 layers of SM, just because of the
thickness of the traces?
If not, why would one lay down extra SM?
Thanks,
Ioan Tempea, ing.
Ingénieur Principal de Fabrication / Senior Manufacturing Engineer
T | 450.967.7100 ext.244
E | [log in to unmask]
W | www.digico.cc
N'imprimer que si nécessaire - Print only if you must
-----Message d'origine-----
De : Guy Ramsey [mailto:[log in to unmask]]
Envoyé : August-19-10 9:26 AM
À : [log in to unmask]
Objet : Re: [TN] Bulging solder on the sides of QFP leads
No, I would not consider it a defect, given the information you have
provided.
IMHO, it is better to optimize toward excess solder than insufficient.
Solder shorts are obvious and easy to troubleshoot, compared to
troubleshooting an intermittent insufficient solder joint.
Guy
______________________________________________________________________
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 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
-----------------------------------------------------
"PLEASE NOTE: The preceding information may be confidential or
privileged. It only should be used or disseminated for the purpose
of conducting business with Parker. If you are not an intended
recipient, please notify the sender by replying to this message and
then delete the information from your system. Thank you for your
cooperation."
______________________________________________________________________
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 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
-----------------------------------------------------
---------------------------------------------------------------------
This transmission (including any attachments) may contain confidential information, privileged material (including material protected by the solicitor-client or other applicable privileges), or constitute non-public information. Any use of this information by anyone other than the intended recipient is prohibited. If you have received this transmission in error, please immediately reply to the sender and delete this information from your system. Use, dissemination, distribution, or reproduction of this transmission by unintended recipients is not authorized and may be unlawful.
______________________________________________________________________
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 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
-----------------------------------------------------
|