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March 2017

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Subject:
From:
"Giamis, Andy" <[log in to unmask]>
Reply To:
TechNet E-Mail Forum <[log in to unmask]>, Giamis, Andy
Date:
Wed, 29 Mar 2017 04:01:18 +0000
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I have used precision blocks to create a picture frame and placed it on a precision flat stone.

-----Original Message-----
From: TechNet [mailto:[log in to unmask]] On Behalf Of Lum Wee Mei
Sent: Tuesday, March 28, 2017 10:14 PM
To: [log in to unmask]
Subject: Re: [TN] IPC-TM-650, 2.4.22, Bow & Twist

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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