My assumption is that the component code (model) is the same which is why
you are seeing the issue on different machines and feeders. The other
variable is the reel, checking lot code and determining if this has always
been an issue or is new issue are critical to the path for fixing the
problem. We just rejected 6 reels of parts because the parts were sticking
in the paper tape due to excessive adhesive on the paper bottom for a
resistor. It was confined to one lot code and the manufacturer has since
changed the process.
Pick up height, if too large a gap the vacuum will suck the part up from the
reel and it can flip. For SOT23's we have a -.10 mm gap.
For 25 mil we have several parts on tape and reel. Packaging is robust and
we have not seen issues with bent leads. We have run 20 mil TSSOP on the
fine pitch placement machine without problems but I would want lead
recognition for those parts so we changed it back to T&R. I guess a lot will
depend on the quality of the placement equipment.
Dave Chapman
Manufacturing Engineer
Circuit Service Inc.
-----Original Message-----
From: Jason W. Gregory [mailto:[log in to unmask]]
Sent: Wednesday, July 09, 2003 11:31 AM
To: [log in to unmask]
Subject: Re: [TN] SOT 23 placed upside down
To help with your first question.....I would do a sample inspection on a
reel to see if the SOT is loaded in the tape upside down. If it is not, it
is flipping during tape pull-back. Are you using HSA or PSA tape? If you
are using PSA, then the adhesive may be mis-registered and grabbing the
part somehow.
For your second question, I would never allow tape and reel for even 50 mil
parts and definitely not 20 or 25 mil.
Jason Gregory
SMT Production Supervisor/
Integrated Product Team Leader
LaBarge Inc.
(918)459-2367
(918)459-2221 fax
[log in to unmask]
http://www.labarge.com
Howard Watson
<Howard.Watson@AM To:
[log in to unmask]
ETEK.COM> cc:
Sent by: TechNet Subject: [TN] SOT 23 placed
upside down
<TechNet@listserv
.ipc.org>
07/09/2003 11:16
AM
Please respond to
"TechNet E-Mail
Forum."; Please
respond to Howard
Watson
Dear Technet folks,
I am obviously not following the search protocol properly for the
information that I need, so I'll just post my Q's anyway. First question
relates to a problem I'm experiencing with some SOT 23's that get placed
upside. This occurs on multiple machines/feeders, and my hunch is that the
component somehow is flipping upside down in the pockets while in the
feeder. Anyone have experience with this problem? I did change the laser
centering parameters so that it gets rejected now if it's upside down, but
I'd like to figure out the root cause.
My second question is regarding QFP components in trays or tape & reel - is
there a standard or recommendation for putting fine pitch QFP's in trays
verses tape & reel? In other words, are 25 or 20 mil pitch gull wing QFP's
OK to be supplied in tape & reel, or should they be in trays to avoid lead
damage? We always get these components in trays, and I figured it was to
protect the leads, but now I wonder if tape & reel is fine. I'm sure it
depends somewhat on the feeders, and their ability to deliver the
components without damaging the leads. Any advice will be greatly
appreciated.
Howard Watson
SMT Manufacturing Engineer
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