Re-check the pad size and pitch of your PWB.  We had the same problem of a
board and found the pad sizes and pitch were outside the recommended
guidelines for the part that was being used.

Bruce Stilmack
GDLS-TO Manufacturing Engineer
(850) 574-4773
[log in to unmask]



                    Steve Gregory
                    <SteveZeva@AO        To:     [log in to unmask]
                    L.COM>               cc:
                    Sent by:             Subject:     Re: [TN] capacitor networks
                    TechNet
                    <[log in to unmask]
                    ORG>


                    02/18/2004
                    09:52 PM
                    Please
                    respond to
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                    E-Mail
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                    Please
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                    SteveZeva






Too much solder volume? Charles said he was using a 5-mil stencil and
having
problems, so suggesting that a rubber squeegee was scooping out more solder
would take that deposit down closer to 4-mils seems extreme to me...for a
1206
chip network anyway. I don't look for 4-mil deposits unless I'm doing
something
like microBGA's, CSP's, or 0201's...certainly not with 1206 chip networks.

I still think it has more to do with termination styles...I've experienced
it.

I  could be wrong...I've been wrong about things before.

-Steve Gregory-
That's what I was thinking.  Could that be why Poh's rubber squeegee
worked,
because it was scavenging some of the solder out of the apertures?

Gary Camac

"Allen T. Maddox" wrote:

> Sounds a little like too much solder volume. Maybe a good idea to reduce
the aperture.
>
>
> Allen Maddox
> Sr. PC Board Designer
> GAI-Tronics, Corp
> 610-796-5854
> PO Box 1060
> Reading, PA 19607-1060
>
> [log in to unmask]
> www.gai-tronics.com
>
> >>> [log in to unmask] 02/17/04 06:56PM >>>
> We have a new assy. that uses 1206 capacitor networks. We are have a
serious
> problem with bridging and unsoldered connections. We think we may have
solved
> the non soldered problem by increasing the soak before reflow but still
have
> the bridging. Anybody have similar experiences? We are using a 5 mil.
> stencil. The other parts all seem to solder well. We are considering
having
> the apertures for these parts reduced. Any suggestions would be greatly
> appreciated.
>
> Charles Caswell
> The Big Kahuna

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