There is thin thermocouple wire that could be fed through the solder
joints of the BGA and go to the center of it. This method would allow to
obtain the profile wanted without drilling. If drilling is the option
chosen,  drill the board without the BGA and use any of several types of
flex masking to plug the holes around the TC wire and to hold the TC wire
down.. After the wires are in place, the BGA can be installed.
        Good luck.
        Ramon

> -----Original Message-----
> From: Tobias.Chang [SMTP:[log in to unmask]]
> Sent: Tuesday, October 22, 2002 3:36 PM
> To:   [log in to unmask]
> Subject:      [TN] drilling hole for thermo-profile
>
> can anyone suggest methods for drilling small holes in PCBs to facilitate
> temperature profiling (putting thermocouples from under the board to the
> surface - under a BGA)
>
> and while i'm at it, can anyone recommend a specific epoxy or adhesive
> that
> can be easily applied to fill up the (small hole), that can handle the
> high
> temperatures, and hold the thermocouple in place?
>
> (i'm told this is the best practice to get accurate temperature profiles
> for
> BGA's - for a rework station, if there are better methods out there i'd be
> glad to hear about those too) =)
>
> thanks,
>
> toby
>
>

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