Leland,
As someone responded previously, re-printing will help with your
insufficients. Even with small pads, if you have a machine with decent
alignment, you won't be able to tell that the board has been through the
machine twice.
On bridges, I've seen people separate solder paste with a dental pick,
but if the bridge is across solder mask, you may find that they fix
themselves through the oven anyway.
Defects of the print typically indicate that your stencil or program is
not optimized, and so an ongoing process to track or fix defects should
not be required.
Ben
-----Original Message-----
From: TechNet [mailto:[log in to unmask]] On Behalf Of Leland Woodall
Sent: Wednesday, January 21, 2009 10:57 AM
To: [log in to unmask]
Subject: [TN] Automated Solder Paste Inspection - Best Practices Request
Technetters,
I sent this out last week during a period of nasty weather across the
country, and of course, got limited responses. I'm trying it again, as
this is quite important.
Please help me if you can.
Thanks!
Leland
-----Original Message-----
From: Leland Woodall
Sent: Thursday, January 15, 2009 2:40 PM
To: 'TechNet E-Mail Forum'
Subject: Automated Solder Paste Inspection - Best Practices Request
Everyone,
We have automated solder paste inspection machines immediately following
each of our screen printers. These all check for volume, height, and
pad coverage. We run only lead-free products, and also have a
requirement that disallows any wiping or cleaning of a misprinted board.
I'm looking for folks running a similar operation that can give me some
recommendations on how they manage this process. How many bridges do
you allow? How do you handle insufficients or inadequate pad coverage?
Insufficient paste volume bothers me, as I'm always afraid our
post-reflow AOI process will not detect the condition. I also hate to
scrap a board that has only a couple of pads with low or no solder.
Any suggestions on how we can minimize scrap but ensure we have no
escapes? Do we write down the effected pads, mark the board, place the
parts, and capture it after the oven? How could one reliably manage
this?
Your comments are sincerely appreciated.
Stay warm!
Leland Woodall
---------------------------------------------------
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
-----------------------------------------------------
|
