Hi Howard,
I dont know what the results would be off dropping a reel but it would be a lot less
damage than dropping a tray and picking the parts off the floor. The machines we
use have a locking feature for all larger reels so that the reels cant be knocked
off if someone collides with them, and I imagine that you could do a simple mod to
one of your feeders if you are worried about this.
Regards,
Chris Murphy
Howard Watson wrote:
>
> Chris & all,
>
> Thanks for all the information. The feedback seems to be split on using trays vs.
> tape & reel for fine pitch QFP's. I think I will slowly migrate to T & R one
> component at a time, evaluating the defect data. One other question for those who
> have success with T & R, what happens if the reel is dropped? I know, just don't
> drop the reel, but I've seen many a reel get knocked off the feeder. On the flip
> side, I have also seen components damaged from trays that were mishandled.
>
> Thanks once again to all for the input - it really helps to hear what others are
> doing.
>
> Howard Watson
> SMT Manufacturing Engineer
> AMETEK/Dixson
>
>
> Chris Murphy <[log in to unmask]>
Sent by: TechNet To:
<[log in to unmask]> [log in to unmask]
cc:
07/10/03 02:22 PM Subject: Re: [TN] SOT
Please respond to "TechNet E-Mail Forum."; 23 placed upside down
Please respond to Chris Murphy
>
>
>
> Hi Howard,
>
> we have been picking fine pitch QFPs up to QFP100 size from tape for years with no
> coplanarity or moisture issues.
> There are no problems with lead damage caused if the tray is knocked by an
> operator when loading the tray into the tray
> feeder and parts jump out, there is no possibility of incorrect rotation caused by
> an operator putting the tray in the
> wrong way around, less downtime from reel / tray changeovers as we can fit many
> more parts onto a reel than a tray, no
> reduced placement efficiency if you have a placment machine with a slow tray
> feeder.
>
> I am curious as to why people are baking their parts? Surely if you keep it in
> it's vacuum package until it is needed
> and store it in dessicant cabinets when off line then it should be OK? (Sorry if
> this is a stupid question.)
>
> Regards,
>
> Chris Murphy,
>
> Production Engineering,
> Tait Electronics
>
> Francois Monette wrote:
>
> > Howard,
> >
> > For your second question, another important consideration for Tape Vs Tray
> > is whether the components are classified moisture-sensitive and what MS
> > level. Even for robust components like BGAs, keep in mind that the benefits
> > you get from tape and reel can be more than offset by the fact that you will
> > have more parts per unit resulting in longer exposure time and especially
> > the longer bake time required. In a high temp tray the default bake cycle is
> > 48 hours at 125C and in a reel it is 79 days at 40C...(ref. J-STD-033A).
> >
> > Francois Monette
> > Cogiscan Inc.
> >
> > Date: Wed, 9 Jul 2003 10:16:59 -0600
> > From: Howard Watson <[log in to unmask]>
> > Subject: SOT 23 placed upside down
> >
> > 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
> > AMETEK/Dixson
> >
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