Hi Jowen,
At the risk of offending the wave soldering fraternity, I have two aims in life. The second is to remove wave soldering from the production process.
My opinion is that reflow soldering gives better quality so I promote double sided reflow where I can . If this involves pin in hole reflow then so be it. The problem is with older designs that have a lot of leaded components so I have to accept wave soldering.
It may be an obvious question, but since the area of these SRAMS is larger than the usual SM components, are you printing/dispensing a larger area of adhesive? Also, when the components become detached, is the fracture surface between the adhesive and the board or between the adhesive and the component. The answer to this may point you in the direction of the cause of the failure.
Regards
Eric Dawson
PS tappity tappity tappity. As somebody observed on this forum a year or so ago, this is my Friday dance. (With acknowledgements to Snoopy).
> -----Original Message-----
> From: Jowan Iven [SMTP:[log in to unmask]]
> Sent: Friday, April 25, 2003 12:26 PM
> To: [log in to unmask]
> Subject: [TN] SRAM on bottomside
>
> Hi there,
>
> One of our customers has put a SRAM (TSOP-54 NEC) on the bottomside of a
> board.
> It is necessary to wavesolder this side so we have to glue this component
> along with the other smd's
> The problem is that these components are very susceptible for boardhandling
> and fall off the board to often before the wavesolderprocess.
> In one way or another the adhesion is not as strong as with "normal"
> components.
> In the past we had the same problem with similar shapes from different
> manufacturers.
> Luckily we were able to solve those problems.
> And I think we can solve this one in the same way.
>
> What then is your problem, I hear you thinking.
> It looks to me that these components are not really designed for
> (glueing,curing and) wavesoldering.
> And I'm looking for some sort of proof or testresults.
> Wether I'm right or wrong, I just would like to know.
>
>
>
> Jowan Iven
>
>
>
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