Lon,

It sounds like your customer may be at fault. I have had experience where
the use of Epoxy type compunds that have exothermic cures, that is, the
compund generates heat during curing, coupled with the heat in a curing oven
was sufficient to generate heat in excess of the melting temperature of
solder! This condition is especially true where a quantity of potting is
dispensed. A 3cm by 5cm area with a 2cm thickness would be enough compund to
cause this to happen. So my suspicion here is that the customer is melting
your solder joints with his compound and oven cure.

If you can give me the name of the compound that your customer is using, I
can give you some suggestions.

Bill Kasprzak
Moog Inc.

> -----Original Message-----
> From: Lon Weffers [SMTP:[log in to unmask]]
> Sent: Wednesday, May 10, 2000 7:03 AM
> To:   [log in to unmask]
> Subject:      [TN] loose components
>
> Hi,
>
> Is one of you technetters familiar with this problem:
>
> For a customer we produce a board (3 by 5 centimeters)with no more then 6
> smt components 1206. When they encapsule the board with a compound one of
> the components looses from the board. They put the compound on the board
> with 30-40 bar pressure and 150deg celsius temperature. It seems to me
> that
> the preesure causes a higher temperature then 150 deg.
> The customer says the soldering joints are bad , but we can't find any
> solderingproblems at all.
>
> Thanks in advance
>
> Lon Weffers
> Matas Electronics bv
> De Dieze 16
> 5684PT Best The Netherlands
> www.matas.nl
>
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