I think this resource provides the type of information and measurement
method asked in the initial inquiry for both PCB and PCBA:
http://akrometrix.com/wp-content/uploads/2016/02/Ready-to-Start-Measuring-PCB-Reflow-Warpage-complete-8_20_13.pdf


On Tue, Mar 28, 2017 at 10:14 PM, Lum Wee Mei <[log in to unmask]> wrote:

> It is this Bow & Twist season again.
> I often wonder whether someone really measured Bow & Twist on assembled
> boards. If yes, wonder how it was done as both sides are already populated
> with components.
>
> ~wee mei~
> ________________________________________
> From: TechNet [[log in to unmask]] on behalf of Joyce Koo [[log in to unmask]]
> Sent: Wednesday, March 29, 2017 3:59 AM
> To: [log in to unmask]
> Subject: Re: [TN] IPC-TM-650, 2.4.22, Bow & Twist
>
> it depends your design. if you have some small parts in the max bow area,
> it may flight out upon installation... (1) your PCB should compliant with
> bow and twist with simulated reflow - how many time you reflow, including
> rework if it required (2) your PCA depend upon what you how you want to
> install or support points and what is density and type of parts... better
> not be Gyro... those need really flat ;-).
> > Fellow TechNetters:
> >
> >    Does the above stated TM applies to raw cards ONLY?   Is there a
> > standard for PCBA?
> >
> > Victor,
> >
>

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