Hi Victor,
I do not know whether there is anything on this in any of the documents, most likely not, since, it is not really important. There is an allowed overhang—so that may be the answer
Solder joint strength has never been an issue for properly wetted SJs; for gullwing leads with a foot length of 3-times the lead width the heel fillet is all-important. For shorter 
lead foot length, the toe fillet becomes also important because short feet 'rock.'
Werner


 


 

-----Original Message-----
From: Victor Hernandez <[log in to unmask]>
To: [log in to unmask]
Sent: Thu, Aug 20, 2009 2:34 pm
Subject: [TN] LF, 1:1 ratio of PWB copper pad to lead width dimension










Fellow TechNetters:

   What is IPC position on the width ratio between the PWB external
copper pad and width of gull wing lead for LF application.  I have seen
minimal side and vertical solder wetting and feel that this is
inadequate interface as the mating strength occurs between the fat
surface only peel strength.

Victor,

---------------------------------------------------
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
-----------------------------------------------------



 


---------------------------------------------------
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
-----------------------------------------------------