In a message dated 11/02/2000 1:24:11 PM Central Standard Time,
[log in to unmask] writes:

> Dear subscribers:
>
>  I have seen in a few of our products some cracked capacitors. The cracks
>  are very small and it is usually very difficult to see them, even under a
>  high maginification microscope. When we reflow one side of the capacitor
>  with the solder iron, the capacitor completely separates. In a few cases I
>  have seen the cracks even before we touch it up with the solder iron, so I
>  know that somehow it is happening before touchup. This problem has been
>  experienced on boards that do not go through the wave. There are other
>  components like resistors and even other capacitors that do not show the
>  same problem, even on the same product. The capacitors are 805s.
>
>  Any ideas as to what is causing this?
>
>  Thanks!
>
>  Arturo Urias
>  National Instruments

Hi Arturo!

Can I ask what kind of pick and place you use? I've seen a similar problem
before with FUJI CP machines. It wasn't because of the machine itself, but
because of some maintenance problems. The nozzels are spring loaded and if
not maintained properly, they can sometimes stick when placing the part,
putting too much pressure on them.

Also, there can be too much pressure placed on the component if the board
supports on the X/Y table are bowing the board upwards instead of keeping the
board flat and level.

I tend to think that it has something to do with your pick and place process
because you said that you notice the problem all across your boards, whether
they are wave soldered or reflowed, resistors and capacitors as well...

Just a thought....

-Steve Gregory-

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