Matt,

I agree with Bill C, stencil relief pockets at the via locations will allow
the high points to be accepted into the bottom of the foil.

Bill Kunkle
MET Assocs

-----Original Message-----
From: TechNet [mailto:[log in to unmask]]On Behalf Of Matt Kehoe
Sent: Friday, March 09, 2007 12:01 PM
To: [log in to unmask]
Subject: [TN] Paste Volume, off contact vs non off contact


We have been processing a family of boards for 3 years. No issues. New PCB
Vendor and the boards suddenly will not print very well. Sloppy printing
definition. Heavy heavy deposition.

Closer inspection reveals that the soldermask is built up .0012-.0019 over
the vias, preventing the stencil from gasketing. Vendor claims they are
built to print.. Opinions?

Pictures at ;
http://www.sipad.com/ssiqa/3942vias.pdf
http://www.sipad.com/ViasBuildup.pdf

The question we are trying to answer is, if your boards came in with mask
this thick over the vias would you feel confident in running them without
modifing the stencil? Would you expect a significant increase in solder
volume?


mk

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